Assessed as Up-to-date:	28 December 2010
Date of Search:	15 December 2009
Next Stage Expected:	15 September 2011
Protocol First Published:	Issue 1, 1999
Review First Published:	Issue 1, 1999
Last Citation Issue:	Issue 2, 2011

Date / Event	Description
28 December 2010 Updated	This updates the review "Longchain polyunsaturated fatty acid supplementation in preterm infants" published in the Cochrane Database of Systematic Reviews (Simmer 2008). Updated search in December 2009 identified two new trials for inclusion in this update (Carnielli 2007; Lapillonne 2000). No changes to the conclusions of the review.
28 December 2010 New citation: conclusions not changed	New first author.

Date / Event	Description
01 April 2010 Updated	This review updates the existing review of "Longchain polyunsaturated fatty acid supplementation in preterm infants" published in The Cochrane Library, Issue 1, 2008 (Simmer 2008). Two trials were added in this update. Results of the added trials confirmed that there are no significant benefits or risks of LCPUFA supplementation of formula for preterm infants. Growth was the only clinical outcome assessed in the two trials identified in this update. Both studies did not report benefits or harms related to LCPUFA supplementation in terms of growth at different time points in different populations.
10 June 2008 Amended	Converted to new review format.
31 August 2007 Updated	This review updates the existing review of "Longchain polyunsaturated fatty acid supplementation in preterm infants" published in The Cochrane Library, Issue 1, 2004 (Simmer 2004). Five trials had been added in the previous update (Simmer 2004). Four trials were added in this update. Results of the added trials confirmed that there are no significant benefits or risks of LCPUFA supplementation of formula for preterm infants. Three out of four added trials reported some benefit for various developmental and growth outcomes at different time points in different populations.

Abstract

Background

Controversy exists over whether longchain polyunsaturated fatty acids (LCPUFA) are essential nutrients for preterm infants, who may not be able to synthesise sufficient amounts of LCPUFA to satisfy the needs of the developing brain and retina.

Objectives

The aim of this review is to assess whether supplementation of formula with LCPUFA is safe and of benefit to preterm infants.

Search methods

Trials were identified by MEDLINE (1966 to December 2009), Oxford Database of Perinatal Trials, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2009) and by checking reference lists of articles and conference proceedings.

Selection criteria

All randomised trials of formula supplemented with LCPUFA and with clinical endpoints were reviewed.

Data collection and analysis

All authors assessed eligibility and trial quality, two authors extracted data separately. Study authors were contacted for additional information.

Results

Of the 17 trials included in the review, 13 were classified as of high quality.

Visual acuity
Visual acuity over the first year was measured by Teller or Lea acuity cards in eight studies, by VEP in six studies and by ERG in two studies. Most studies found no significant differences in visual assessment between supplemented and control infants.

Development
Three out of seven studies reported some benefit of LCPUFA on neurodevelopment in different populations at different postnatal ages. Meta-analysis of Bayley Scales of Infant Development of four studies at 12 months (N = 364) and three studies at 18 months (N = 494) post-term showed no significant effect of supplementation on neurodevelopment.

Growth
Four out of 15 studies reported benefits of LCPUFA on growth of supplemented infants at different postnatal ages. Two trials suggested that LCPUFA supplemented infants grow less well than controls. One trial reported mild reductions in length and weight z scores at 18 months. Meta-analysis of five studies showed increased weight and length at two months post-term in supplemented infants. Meta-analysis of four studies at 12 months (N = 271) and two studies at 18 months (N = 396) post-term showed no significant effect of supplementation on weight, length or head circumference.

Authors' conclusions

Infants enrolled in the trials were relatively mature and healthy preterm infants. Assessment schedule and methodology, dose and source of supplementation and fatty acid composition of the control formula varied between trials. On pooling of results, no clear long-term benefits or harms were demonstrated for preterm infants receiving LCPUFA-supplemented formula.

Plain language summary

Longchain polyunsaturated fatty acid supplementation in preterm infants

There is not enough evidence to show that supplementing formula for preterm babies with longchain polyunsaturated fatty acids (LCPUFA, usually fish oil) improves their early sight development and intelligence. Babies fed with breast milk are believed to have more mature sight skills and a higher IQ (Intelligence Quota) than babies fed with formula. It has been suggested that the relatively high levels of longchain polyunsaturated fatty acids (LCPUFA) found in breast milk, may contribute to the higher IQ levels and sight skills. Some formulas are available with added LCPUFA usually as fish oil. The review of trials found the evidence does not support the claim that preterm infants have improved visual and intellectual development if their formula is supplemented with LCPUFA. In addition, LCPUFA supplementation does not significantly influence the long-term growth of preterm infants.

Background

Description of the condition

Dietary fat in infancy is fundamental for the provision of energy for rapid growth, fat soluble vitamins and essential fatty acids. However, the type of fat required is controversial and interest has recently focused on the importance of LCPUFA such as docosahexaenoic acid (DHA) and arachidonic acid (AA). These fatty acids are found in high proportions in the structural lipids of cell membranes, particularly those of the central nervous system, and their accretion primarily occurs during the last trimester of pregnancy and the first year of life (Clandinin 1980).

During pregnancy, DHA and AA cross the placenta to the fetus. Postnatally, these fatty acids are supplied in breast milk, which contains a full complement of all PUFA including precursors and metabolites. However, most infant formulae contain only the precursor essential fatty acids (EFA), ALA (omega 3 precursor) and LA (omega 6 precursor) from which formula-fed infants must synthesise their own DHA and AA respectively. The absence of LCPUFA in formula may be further exacerbated by inhibition of incorporation of endogenously produced LCPUFA by the high concentrations of LA currently in most formulae.

Description of the intervention

Biochemical studies in both term and preterm infants indicate that formula-fed infants have significantly less DHA and AA in their erythrocytes relative to those fed breast milk (Clark 1992). This suggests that infant formulae containing only LA and ALA may not be effective in meeting the full EFA requirements of infants.

Biochemical studies of LCPUFA are clinically relevant as dietary fatty acid supply may affect physiological function. In non-randomised, observational studies, term infants fed breast milk have been found to have more mature visual acuities and higher DHA levels than those receiving formula. Further, their acuities were positively correlated with erythrocyte DHA levels (Makrides 1993).

How the intervention might work

Evidence to suggest that breast fed infants have a long term IQ advantage over those who have been fed formula has been evident in the literature for many years (Morrow-Tlucak 1988; Lucas 1992; Anderson 1999; Kramer 2008). As most of these studies are not randomised, the majority of comparisons between breast fed and formula-fed infants are confounded by genetic and socioeconomic factors. These studies do not relate their findings to fatty acid supply. However, some reports suggest that the low levels of LCPUFA, such as DHA, found in formula-fed infants may contribute to the lower IQ scores reported in formula fed infants (Bjerve 1992; Neuringer 1986).

Why it is important to do this review

There are few prospective studies investigating the effect of DHA supply on long-term development. Randomised trials comparing standard formula and supplemented formula are necessary to address the issue of whether LCPUFA are essential nutrients in infancy before supplementation of formula with LCPUFA becomes routine, at considerable cost without the long-term risks and benefits being determined.

Objectives

The aim of this review is to assess whether supplementation of formula with LCPUFA is safe and of benefit to preterm infants. The main areas of interest are the effects of LCPUFA supplementation on the visual function, development and growth of preterm infants.

Methods

Criteria for considering studies for this review

Types of studies

Only randomised clinical trials with at least six weeks of follow-up were considered.

Types of participants

Trials involving enterally-fed preterm (< 37 weeks gestation) infants were considered.

Types of interventions

Different LCPUFA supplements were included as different oils have been used to increase the DHA levels in the plasma and erythrocytes of infants (e.g. fish, fungal and egg phospholipid).

Types of outcome measures

Trials with clinical outcomes (visual development, general development, growth) were included. Trials reporting only biochemical outcomes were not included.

Search methods for identification of studies

Data collection and analysis

Data collection forms were compiled and completed independently by at least two of the review authors. Authors of ten studies were contacted in writing to clarify existing or provide missing data and a response was received from five (Lapillonne 2000; O'Connor 2001; Groh-Wargo 2005; Clandinin 2005; Koletzko 2003).

Abbreviations used in this review include: LCPUFA longchain polyunsaturated fatty acids, n- omega, LA linoleic acid (18:2n-6), ALA alpha linolenic acid (18:3n-3), AA arachidonic acid (20:4n-6), DHA docosahexaenoic acid (22:6n-3), EFA essential fatty acids, EPA eicosapentaenoic acid (20:5n-3), GA gestational age, BW birthweight, VEP visual evoked potential, ERG electroretinogram, ACP acuity card procedure, FPL forced preferential looking, PDI psychomotor developmental index, MDI mental developmental index, RBC red blood cell, PMA postmenstrual age, TBARS thiobarbituric acid reactive substances.

Selection of studies

All randomised trials of formula supplemented with LCPUFA and with clinical endpoints were reviewed.

Data extraction and management

Two of the three review authors separately extracted, assessed and coded all data for each study using a form that was designed specifically for this review. For each included study, information was collected regarding the method of randomisation, blinding, intervention, stratification, and whether the trial was conducted at a single centre or multiple centres. Information regarding inclusion criteria, including gestational age, and postnatal age at the time of treatment. Differences in assessment were resolved by discussion. For each study, final data was entered into RevMan by one review author and then checked by a second review author. Any disagreements were addressed by the third reviewer.

Assessment of risk of bias in included studies

The standard methods of the Cochrane Neonatal Review Group were employed. The methodological quality of the studies were assessed using the following key criteria: allocation concealment (blinding of randomisation), blinding of intervention, completeness of follow-up, and blinding of outcome measurement/assessment. For each criterion, assessment was yes, no, can't tell. Two review authors separately assessed each study. Any disagreement was resolved by discussion. This information was added to the Characteristics of Included Studies Table.

In addition, for the update in 2010, the following issues were evaluated and entered into the Risk of Bias Table:

1) Sequence generation (checking for possible selection bias). Was the allocation sequence adequately generated?

For each included study, we categorized the method used to generate the allocation sequence as:

- adequate (any truly random process e.g. random number table; computer random number generator);

- inadequate (any non random process e.g. odd or even date of birth; hospital or clinic record number);

- unclear.

(2) Allocation concealment (checking for possible selection bias). Was allocation adequately concealed?

For each included study, we categorized the method used to conceal the allocation sequence as:

- adequate (e.g. telephone or central randomisation; consecutively numbered sealed opaque envelopes);

- inadequate (open random allocation; unsealed or non-opaque envelopes, alternation; date of birth);

- unclear.

(3) Blinding (checking for possible performance bias). Was knowledge of the allocated intervention adequately prevented during the study? At study entry? At the time of outcome assessment?

For each included study, we categorized the methods used to blind study participants and personnel from knowledge of which intervention a participant received. Blinding was assessed separately for different outcomes or classes of outcomes. We categorized the methods as:

- adequate, inadequate or unclear for participants;

- adequate, inadequate or unclear for personnel;

- adequate, inadequate or unclear for outcome assessors.

(4) Incomplete outcome data (checking for possible attrition bias through withdrawals, dropouts, protocol deviations). Were incomplete outcome data adequately addressed?

For each included study and for each outcome, we described the completeness of data including attrition and exclusions from the analysis. We noted whether attrition and exclusions were reported, the numbers included in the analysis at each stage (compared with the total randomised participants), reasons for attrition or exclusion where reported, and whether missing data were balanced across groups or were related to outcomes. Where sufficient information was reported or supplied by the trial authors, we re-included missing data in the analyses. We categorized the methods as:

- adequate (< 20% missing data);

- inadequate (≥ 20% missing data):

- unclear.

(5) Selective reporting bias. Are reports of the study free of suggestion of selective outcome reporting?

For each included study, we described how we investigated the possibility of selective outcome reporting bias and what we found. We assessed the methods as:

- adequate (where it is clear that all of the study’s pre-specified outcomes and all expected outcomes of interest to the review have been reported);

- inadequate (where not all the study’s pre-specified outcomes have been reported; one or more reported primary outcomes were not pre-specified; outcomes of interest are reported incompletely and so cannot be used; study fails to include results of a key outcome that would have been expected to have been reported);

- unclear.

(6) Other sources of bias. Was the study apparently free of other problems that could put it at a high risk of bias?

For each included study, we described any important concerns we had about other possible sources of bias (for example, whether there was a potential source of bias related to the specific study design or whether the trial was stopped early due to some data-dependent process). We assessed whether each study was free of other problems that could put it at risk of bias as:

- yes; no; or unclear.

If needed, we planned to explore the impact of the level of bias through undertaking sensitivity analyses.

Measures of treatment effect

The standard methods of the Neonatal Review Group were used. Statistical analyses were performed using Review Manager software. Categorical data were analysed using relative risk (RR), risk difference (RD) and the number needed to treat (NNT). Continuous data were analysed using weighted mean difference (WMD). The 95% Confidence interval (CI) was reported on all estimates.

Assessment of heterogeneity

We estimated the treatment effects of individual trials and examine heterogeneity between trials by inspecting the forest plots and quantifying the impact of heterogeneity using the I-squared statistic. If we detected statistical heterogeneity, we planned to explore the possible causes (for example, differences in study quality, participants, intervention regimens, or outcome assessments) using post hoc subgroup analyses (in future updates).

Data synthesis

The meta-analysis was performed using Review Manager software (RevMan 5), supplied by the Cochrane Collaboration. For estimates of typical relative risk and risk difference, we used the Mantel-Haenszel method. For measured quantities, we used the inverse variance method. All meta-analyses were done using the fixed effect model.

Subgroup analysis and investigation of heterogeneity

No subgroup analyses were performed.

Results

Description of studies

Twenty-one randomised studies assessing the clinical effects of feeding formula supplemented with LCPUFA were identified. Details of the patients and methods of the 17 trials included in this review are summarised in the Table, Characteristics of Included Studies. Details of four excluded studies (Donzelli 1996; Koletzko 2003; Lim 2002; Rodriguez 2003) are summarised in the Table, Characteristics of Excluded Studies.

The composition and dose of LCPUFA supplement varied. Some studies supplemented with only n-3 fatty acids and some with n-3 and n-6 fatty acids. If infants were randomised to more than one supplement, the supplement that contained both n-3 and n-6 LCPUFA was selected for the comparison over one containing only n-3. If the two supplements were n-3 and n-6 as fish/fungal oil or egg-TG/fish oil, we chose the fish/fungal group as microbial oils are more similar to human milk fat than egg-TG. For this review, if more than one control group was included, the control group receiving a formula with a LA:ALA ratio most like breast milk was selected.

Risk of bias in included studies

The quality of the trials was assessed predominantly based on method of randomisation, blinding of intervention, blinding of outcome assessment, and completeness of follow-up, giving attention to the possibility of selection bias, performance bias, exclusion bias and detection bias. Details of the methodological quality of all included studies are given in the Table, Characteristics of Included Studies.

The Uauy 1990; Carlson 1992; Clandinin 1997; Hansen 1997; Vanderhoof 1999; Lapillonne 2000; O'Connor 2001; Fewtrell 2002; Innis 2002; van Wezel 2002; Fewtrell 2004 and Groh-Wargo 2005 trials were assessed to be of good quality. The trial Clandinin 2005 in general was of good quality, but follow-up rate was poor (44 to 60 %). Fang 2005 and Carnielli 2007 were assessed to be of moderate methodological quality due to small sample size (N = 28 and N = 22, respectively) and uncertainty regarding adequacy of allocation concealment and method of randomisation. The Carlson 1996 and Fadella 1996 trials were not classified as of high quality despite blinded assessment and complete follow-up due to problems with assessment methodology. The developmental assessment tool changed in the middle of the Carlson 1996 trial whereas Fadella 1996 used methodologies for VEP & ERG assessments that deviate from generally accepted international standards.

Effects of interventions

Visual development - assessment methods

Visual acuity is a measure of the smallest element that can be resolved and may be assessed in infants by using gratings which consist of black and white stripes or checkerboard patterns. Grating acuity can be measured by using behavioural (Teller acuity cards) or visual evoked potential (VEP) methods. Each pairing of a black and white stripe is referred to as a cycle and the spatial frequency of a grating is defined by the number of cycles per degree of viewing angle. As grating spatial frequency increases, the stripes become finer and are more difficult to discriminate, eventually appearing as an even grey to the observer. Grating acuity is the highest spatial frequency where the stripes can be resolved.

The VEP is the electrical activity of the brain that is generated in response to a reversing contrast checkerboard or grating. The VEP is recorded from an electrode placed over the occipital pole. The amplitude of the VEP increases linearly with spatial frequency near the visual acuity threshold. Linear regression is used to fit a straight line through the linear portion of the VEP amplitude versus spatial frequency curve and visual acuity is determined from the intercept of the regression line with the spatial frequency axis. Studies in this review have used different methods for assessing VEP (transient, steady state and sweep VEP). Transient VEP reflects a slow pattern reversal rate and records individual responses where the brain has time to recover after each reversal. A steady state VEP reflects a quick pattern reversal rate in which the next evoked response is actually evoked before the previous one has finished. The evoked responses hence run into each other so the output looks almost like a sine wave. The faster the reversal rate the more condensed the wave. The sweep/swept VEP is also a steady state technique but uses a different stimulus-usually stripes (instead of checks) that sweep through from the largest to the smallest in about 10 seconds.

Behavioural methods for assessing visual acuity rely on the strong preference shown by infants for patterned stimuli over non-patterned stimuli. Both the acuity card procedure (ACP) and the forced preferential looking (FPL) procedure have been used in conjunction with the Teller acuity cards for measuring the development of visual acuity in infants. The FPL procedure tests binocular grating acuity; the tester views the infant behind a blind through a peephole, without knowledge of the spatial-frequency gratings on the cards, and makes a forced-choice judgement about which card the infant prefers. Individual acuities are converted to log cycles/degree and SD are in octaves which are determined by dividing one log SD by 0.3. The Lea acuity cards test uses a similar methodology but does not require blinds between examiner and child. The 'Hiding Heidi' low contrast test is a contrast sensitivity test using pictures with facial features (i.e. 'Hiding Heidi') presented at varying levels of contrast. The child's physical response to a particular card suggests the child sees 'Hiding Heidi' at that level of contrast.

Electroretinogram (ERG) is an assessment of retinal function. The more mature the retinal function, the lower the threshold required to elicit a response, and the higher the maximum amplitude recorded (threshold and Vmax are reported in log units).

For this review, most of the visual data is analysed as mean+/- SD in log values. This form of data presentation and the varying assessment methods preclude the use of meta-analysis.

Visual development - results

Visual acuity using Teller cards was measured in the Carlson 1992 and Carlson 1996 studies. In the 1993 study, the supplement was fed until 12 months and visual acuity was better in the supplemented group at two and four months post-term but not at six, nine, and twelve months (the data are published in Figures only and therefore cannot be included in the Tables for this review). In the 1996 study, LCPUFA supplementation was fed until two months post-term and visual acuity assessed over 12 months post-term. At two months, the supplemented infants without bronchopulmonary dysplasia (BPD) had better visual acuity compared with control but supplemented infants with BPD had poorer visual acuity compared with controls. No differences between supplemented and control groups (with or without BPD) were detected at four, six, nine and twelve months.

In the Hansen 1997 study, visual acuity was also assessed with Teller acuity cards and no difference was documented between supplemented and control infants at two and four months post-term.

Fadella 1996 assessed vision using the flash VEP; waveforms of the supplemented group were of different morphology and some of shorter latency than those of the control group - the latencies of N4 and P4 were shorter in the supplemented group but the latencies of N2, P2, N3 and P3 were not significantly different between the groups. There are concerns with the methodology of assessment in this study in that it deviates from international standards (International Society for Clinical Electrophysiologists in Vision). Therefore, the data reported are difficult to interpret and sensitivity may have been decreased so much that changes due to the intervention may not have been detected.

Uauy 1990 measured visual acuity at two months post-term using visual evoked potentials (VEP) and Teller acuity cards and report that the LCPUFA supplemented infants had better visual acuity (data were not available for this review). Uauy 1990 also assessed retinal function. The authors used contact lens electrodes and dark adapted all subjects to measure rod ERG. They demonstrated that Vmax for rod function measured by the ERG was higher in supplemented infants when compared with control infants at 36 weeks postmenstrual age (PMA) but there were no significant differences at four months post-term. The function of the cones, which are more mature at birth, was not affected (data not included in this review).

Fadella 1996 measured ERG at 52 weeks PMA or three months post-term. There were no significant differences between the groups in ERG (a and b latencies, and a-b amplitude), however, subjects were not dark-adapted, their pupils were not dilated and electrodes were placed on the forehead instead of using contact lens or gold foil electrodes. Fadella 1996 also measured auditory evoked responses at 52 weeks postmenstrual age and found no differences between the groups (nine latencies measured, these results are not listed in this review but are available in the publication).

Innis 2002 measured visual acuity (Teller acuity cards) at two and four months post-term and found no difference between supplemented and control groups.

O'Connor 2001 measured visual acuity by Teller acuity cards at two, four and six months post-term and found no difference between supplemented and control groups. However, swept-parameter VEP was better in the supplemented groups compared with control group in a subgroup of infants at six months post-term. van Wezel 2002 also reported no significant differences in visual acuity between the supplemented and control groups at three and twelve months post-term by flash VEP and at three, six, twelve and fourteen months post-term by Teller acuity cards. However, the sample size in this study was small and calculated on cerebral myelination assessed by magnetic resonance imaging. They found no significant difference in cerebral myelination between groups.

Fang 2005 measured visual acuity by steady state VEP, response to Lea grating acuity cards and 'Hiding Heidi' low contrast cards at four and six months after enrolment and found no difference between supplemented and control groups.

Development

Carlson 1992 and Carlson 1996 reported the results of the Fagan Infantest of development at 12 months. Data were also published at six and nine months for the 1993 study but not included in this review. The Fagan Infantest measures novelty preference based on the observation that after habituation to a familiar stimulus has occurred, a preference will be shown for a different (novel) stimulus if both the familiar and novel stimuli are presented together. A novelty preference score is derived for the average percent of total time spent viewing the novel stimuli on ten discrete paired comparison tests. Infants with average scores of > 57% are said to have a significant novelty preference i.e. the time spent looking at the novel stimuli compared that spent looking at the familiar stimuli is greater than by chance alone. Novelty preference has been interpreted as an early measure of information processing capacity (Fagan 1970). Only a subset of the Carlson 1996 cohort was assessed by the same version of the Fagan test as the Carlson 1992 cohort and so the meta-analysis was limited to the subset of 1996 cohort. Contrary to their hypothesis, novelty preference was lower in the supplemented group. However, the number of looks was higher and the duration of each look was shorter in the supplemented group, which the investigators thought may indicate better cognition.

The Carlson 1992 study reported Bayley developmental scores at 12 months. Mean psychomotor developmental index (PDI) was lower in the supplemented group. Fewtrell 2002 reported Bayley Scales of Infant Development (BSID) and Knoblock, Passamanik & Sherrard's Developmental Screening Inventory at nine and 12 months and found no difference between groups. O'Connor 2001 measured BSID at 12 months and van Wezel 2002 at 12 and 24 months post-term and no significant differences were reported between groups. Clandinin 2005 reported BSID at 18 months post-term and found a trend towards higher Bayley MDI and PDI in algal/fungal oil supplemented vs control infants. Fang 2005 measured BSID at 6 and 12 months post-term and found higher MDI (mean difference 8.2 points, 95% CI 2.31, 14.09) and PDI (mean difference 11.3 points, 95% CI 3.51, 19.09) scores in supplemented vs control group at 12 but not six months. Fewtrell 2004 reported Knoblock, Passamanik & Sherrard's Developmental Screening Inventory at 9 months, and BSID at 18 months post-term and found no significant difference between groups. In the pre-specified subgroup analysis of boys, Bayley MDI but not PDI at 18 months was higher in the supplemented vs. control group (mean difference 5.7 points, 95% CI 0.3, 11.1).

Meta-analysis of BSID of four studies at 12 months (N = 364, Figure 1 and Figure 2) and three studies at 18 months (N = 494, Figure 3 and Figure 4) post-term showed no significant effect of supplementation on neurodevelopment.

Growth and side effects

Growth was measured in fifteen studies. In Carlson 1992, data were taken from the published figures of z-scores, as only mean absolute values were published. Z-scores are normalised growth parameters and express growth in standard deviations from the mean.

Data from the Carlson 1992 and Carlson 1996 studies suggest that normalised weight (but not length and head circumference) is lower in preterm infants who receive supplemented formula when compared with controls. In the Uauy 1990; Fadella 1996; Clandinin 1997 and Vanderhoof 1999 studies, growth (weight, length and head circumference) was not affected by the supplement. In the Hansen 1997 trial, weight was higher at two months post-term in the supplemented group compared with controls, but not significantly different at four months post-term. O'Connor 2001 measured anthropometrics at term, two, four, six, nine and 12 months post-term and reported change in weight, length and head circumference over time. They reported no significant difference in growth parameters between supplemented and control groups (when comparing 'intent to treat' groups and subgroups who received > 80% enteral feed as trial formula). Of interest, length gain was greater among < 1250 g infants in the control vs. supplemented group (5.74 vs. 5.67 mm/wk, p = 0.008). Authors have been contacted for data on absolute weights for meta-analysis.

Innis 2002 measured growth at term, two and four months and found supplementation enhances weight and length gains (data for head circumference not given). Vanderhoof 1999 measured growth at term, two and 12 months and found no difference between the groups. Lapillonne 2000 measured weight, length and head circumference at study entry, discharge, term, three and six months post-term and found no difference between the groups. Fewtrell 2002 found no difference in z-scores but a reduction in absolute weight and length in the supplemented group at 18 months post-term. Clandinin 2005 measured weight, length and head circumference from term to 18 months post-term. Supplemented infants had increased weight at 12 months and greater length at 2, 9 and 12 months. There were no differences in head circumference at any given time point between supplemented and control infants. Fang 2005 measured anthropometrics at one, two, three, four, five, six and 12 months after enrolment and found no difference between groups. Fewtrell 2004 measured weight, length and head circumference at discharge from the hospital, nine months and 18 months post-term and found no difference between groups at any given time point, although weight gain and length gain between birth and nine months post-term were greater in the supplemented vs. control group (weight gain: mean difference 310 g, 95% CI 30, 590; length gain: mean difference 0.9 cm, 95% CI 0.02, 1.9). In the pre-specified subgroup analysis of boys, weight and weight gain to 9 months and length gain to 18 months were higher in the supplemented vs. control group. Groh-Wargo 2005 measured anthropometrics at term, four and 12 months post-term and found no difference between groups. Carnielli 2007 measured weight at seven months postnatal age and found no difference between groups.

Combining results indicated that supplementation infants had increased length at two months post-term (Uauy 1990; Carlson 1996; Vanderhoof 1999; Innis 2002, n = 297, Figure 5) and increased weight at two months post-term (Uauy 1990; Carlson 1996; Vanderhoof 1999; Innis 2002, Hansen 1997, n = 485, Figure 6). Reduction of weight z-scores in supplemented infants was only reported in Carlson 1992 and Carlson 1996 at 12 months ( n = 116, Figure 7). Meta-analysis of four studies at 12 months (N = 271, Figure 8; Figure 9; Figure 10) and two studies at 18 months (N = 396, Figure 11; Figure 12; Figure 13) post-term showed no significant effect of supplementation on weight, length or head circumference.

Uauy 1990 found no significant difference in bleeding time between groups at 34 weeks postconceptional age (2.15+/-0.69, n = 22 vs. 1.68+/-0.66, n = 20). There were no differences in bleeding time at four months post-term. They also measured lipid peroxidation status by malonyl dialdehyde production (thiobarbituric acid-reactive substances) and by fragility determination of peroxide-stressed RBC and found no difference between LCPUFA supplemented and control groups (5.33+/-1.00, n = 30 vs 7.24+/-0.97, n = 28 (TBARS -azide/+azide x 100%). Similarly, there was no difference between the groups in membrane fluidity assessed by diphenylhexatriene fluorescence polarisation.

Discussion

Pooling of data from 17 RCTs does not indicate a long-term benefit of LCPUFA supplementation of formula on visual development, neurodevelopment or growth of preterm infants.

Visual acuity was measured by Teller and Lea acuity cards in eight studies, by VEP in six studies and ERG was assessed in two studies. Results cannot be added in this review because log units are used. Most studies found no differences in any visual assessment between supplemented and control infants (exceptions are Uauy 1990 and O'Connor 2001 studies where VEP acuity was more mature at two months post-term, and at 6 months post-term in a subgroup of supplemented infants respectively).

The Fagan Infantest measures novelty preference which, under controlled conditions, has moderate predictive validity for performance in standardised intelligence tests in childhood (Fagan 1983). Normal infants should have a novelty preference with the mean novelty preference for term infants being 62%. Carlson 1992 and Carlson 1996 demonstrated lower novelty preferences in the supplemented compared with the control group. Despite this, the investigators concluded that supplemented preterm infants may have more rapid visual information processing given that they had more looks and each look was of shorter duration. Most other studies assessed neurodevelopment by BSID with three out of seven studies reporting some benefit of LCPUFA in different populations of supplemented infants at different postnatal ages (Clandinin 2005; Fewtrell 2004; Fang 2005).

LCPUFA supplementation appears safe in preterm infants when growth is used as the safety parameter. Four out of fifteen studies reported benefits of LCPUFA on growth of supplemented infants at different postnatal ages (Hansen 1997; Innis 2002; Clandinin 2005; Fewtrell 2004). However, Carlson 1992, Carlson 1996 suggest that preterm infants fed n-3 LCPUFA supplements grow less well than controls and they give some evidence that poor growth in their studies may be due to a reduction in AA levels which occurs when n-3 supplements alone are used. Recent studies add AA to the supplement and usually find no significant negative effect on growth. The only exception is Fewtrell 2002 where mild reductions in length and weight z-scores were reported at 18 months. Contrary to these results, meta-analysis of five studies (Uauy 1990; Carlson 1996; Hansen 1997; Vanderhoof 1999; Innis 2002) showed increased weight and length at two months post-term in supplemented infants.

No clear long-term benefits on visual or intellectual development have been demonstrated on pooling data from RCT. The justification for adding LCPUFA to formula is based on the rationale of mimicking the composition of human milk and not on evidence of important clinical benefits. A supplement containing a balance of n-3 and n-6 LCPUFA is unlikely to impair the growth of preterm infants. Overall, methodology varies considerably between studies making a summary of the combined data difficult. Some of the disparity between findings may be due to different combinations of LCPUFA in the supplement and different concentrations of essential fatty acids in the control formula. Higher ALA and lower LA:ALA will favour DHA synthesis. Another variable is the medical complications and treatments associated with preterm birth with most studies only enrolling relatively healthy formula-fed infants. More recent RCTs of high-dose DHA supplements given to breast milk-fed preterm infants have reported some positive neurodevelopmental outcomes in the intervention group (Henriksen 2008; Makrides 2009). The dose of DHA in these trials was higher than that used in all the formula studies included in this review, and the breast milk-fed preterm infants were of considerably lower gestational age, i.e., at higher baseline risk of neurodevelopmental delay compared to preterm infants enrolled in formula studies.

Authors' conclusions

Implications for practice

The data from RCTs of LCPUFA-supplemented formula do not support the suggestion that supplementation of formula benefits the development of preterm infants. Providing an optimal ratio of linoleic to alpha linolenic acid (the precursors of LCPUFA), and sufficient alpha linolenic acid for infants to synthesise their own docosahexaenoic acid (DHA), may be adequate. No harm has been demonstrated with respect to growth when formula is supplemented with LCPUFA (DHA and AA).

Implications for research

The methodology as well as the composition of the LCPUFA supplemented and the control formulas have shown little consistency in the trials conducted so far. These data combined with data from RCTs of LCPUFA supplementation of human milk are useful in deciding the best dose and source of LCPUFA supplement to use in future studies, preferably including more immature preterm infants who are at risk of developmental delay.

Acknowledgements

We gratefully acknowledge the assistance of Dr Maria Makrides with interpretation of VEP.
We also thank Dr Sharon Groh-Wargo, Dr Deborah Diersen-Schade, Prof Berthold Koletzko, and Prof Alexandre Lapillonne for provision of additional data and/or clarification of study methodology.

Editorial support of the Cochrane Neonatal Review Group has been funded with Federal funds from the Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Department of Health and Human Services, USA, under Contract No. HHSN267200603418C.

Contributions of authors

2000 original review:
KS: Design and preparation of protocol, literature search, assessment of eligibility and quality of studies, data extraction and data analysis, writing of manuscript.

2004 review update:
KS: Assessment of eligibility and quality of studies, review of manuscript.
SP: Literature search, assessment of eligibility and quality of studies, data extraction and data analysis, writing of manuscript.

2008 review update:
KS: Review of manuscript, guidance and supervision for planning of the meta-analysis.
SMS: Literature search, assessment of eligibility and quality of studies, data extraction and data analysis, writing of manuscript.
SP: Literature search, assessment of eligibility and study quality, review of manuscript.

2010 review update:
SMS: Literature search, assessment of eligibility and quality of studies, data extraction and data analysis, writing of manuscript.
SP: Assessment of eligibility and study quality, data extraction, review of manuscript.
KS: Assessment of eligibility and study quality, review of manuscript, guidance and supervision for update of the meta-analysis.

Declarations of interest

None.

Differences between protocol and review

Published notes

Characteristics of studies

Characteristics of included studies

Carlson 1992

Methods	Randomisation, intervention and outcome assessment were blinded and follow-up of subjects was complete.
Participants	Entry criteria included no need for mechanical ventilation and no significant intraventricular haemorrhage or retinopathy of prematurity. 10 subjects who could not tolerate enteral feeds were replaced. Seventy-nine infants were enrolled, 67 completed study (33 supplemented, 34 control). Subjects were predominantly from lower socio-economic groups and black. Supplemented group GA 29+/-2w, BW 1074+/-193g. Control group GA 29+/-2w, BW 1133+/-163g.
Interventions	Preterm formula (PT) until discharge (approximately 1800g) then term formula (T). Supplemented formula 18.7% & 32.6% (PT & T) LA, 3.1% & 4.9% (PT & T) ALA, 0.3% EPA, 0.2% DHA. Control formula 19.1% & 33.1% (PT & T) LA, 3.0% & 4.8% (PT & T) ALA.
Outcomes	Visual acuity (Teller acuity cards) and growth at term (0m), and 2,4,6.5,9&12m post-term. Fagan infant test at 6.5, 9 and 12m post-term. Red blood cell and plasma fatty acids.
Notes	Visual acuity and growth parameters given in Figures; investigators contacted for actual values but no response.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Unclear	Can't tell
Allocation concealment?	No	Blinding of randomisation: No
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes	Yes
Free of other bias?	Yes	Yes

Carlson 1996

Methods	Randomisation, intervention and outcome assessment were blinded. Follow up was complete. Infants were randomised by sealed envelopes, stratified by gender.
Participants	Ninety-four infants were recruited and 59 completed study through to 4m. Selection criteria included birthweight between 747 and 1275g. More controls dropped out than supplemented infants and replacements were added to balance the groups. Forty percent of subjects had bronchopulmonary dysplasia (defined as an oxygen requirement for > 28 days) which is associated with impaired vision and development. Therefore, data are given for subgroups of infants with or without bronchopulmonary dysplasia. Supplemented group for visual acuity GA 28.5+/-1.2w, BW 1069+/-153g no BPD & GA 27.0+/-1.1w, BW 947+/-130g with BPD vs in control group GA 28.6+/-1.3w, BW 1112+/-106g no BPD & GA 27.5+/-1.6w, 975+/-151g. For the Fagan test of infant development , supplemented group GA27.9+/-1.5, BW 1027+/-153g, n=15 vs control GA 28.2+/- 1.5w, BW 1050+/-149g, n=12.
Interventions	Supplemented formula fed from 3-5 days of age to 48w PCA. Supplemented formula 21.2% LA, 2.4% ALA, 0.06% EPA, 0.20% DHA vs control formula 21.2% LA, 2.4% ALA. All fed standard formula from 2m PCA to 12m PCA (34.3% LA, 4.8% ALA).
Outcomes	Visual acuity (Teller acuity cards), plasma fatty acids and growth (including normalised data). Fagan test of infant development were reported for a subset at 12m.
Notes	Change of test format for infant development resulted in a smaller sample size than planned (sample size required n=60, sample size assessed n=27) - the authors comment on type 2 error resulting from the unplanned loss of power. Only the results from infants tested with the same version of the Fagan test used in their 1993 study were published and therefore available for the review.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Unclear	Can't tell
Allocation concealment?	Yes	Blinding of randomisation: Yes (sealed envelopes) Stratification by gender
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Carnielli 2007

Methods	Infants were randomised to 2 groups to receive supplemented or control formula. Method of randomisation and concealment of random allocation unclear. Blinding of intervention unclear. Outcome assessors were blinded. Follow-up complete (100 %).
Participants	Healthy preterm infants (n=22), 'normally growing', were randomised to supplemented or control formula. Specific health characteristics, age at enrolment, and milk and caloric intake are not reported. Exclusion criteria not reported. Gestational age and birth weight in LCPUFA vs. control groups were 31.0 +/- 2.0 w vs. 31.0 +/- 2.0 w, and 1.16 +/-0.27 kg vs. 1.15 +/-0.36 kg, respectively).
Interventions	Infants in both groups were fed study formulae (80 kcal/100 mL) from enrolment until 7 months postnatal age. Composition of study formulae was nearly identical except for DHA and AA which were not present in control formula. Supplemented formula contained 0.64% DHA and 0.84% AA derived from single-cell oils.
Outcomes	Plasma phospholipid fatty acids, estimation of endogenous LCPUFA synthesis, weight at 7 months postnatal age.
Notes

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Unclear	Can't tell
Allocation concealment?	Unclear	Blinding of randomisation: Can't tell
Blinding?	Yes	Blinding of intervention: Can't tell Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Clandinin 1997

Methods	Intervention and outcome assessments were blinded and all subjects were followed.
Participants	Medically stable preterm infants (n=84), with birth weights appropriate for gestational age (AGA), who were receiving full enteral feeds by day 14 were randomised to control or one of three supplemented formulae. Infants were excluded or withdrawn (n=18) if they received parenteral nutrition after 14 days of age, or they received steroids, red cell or plasma transfusions, or intravenous lipid after 8 days of age. Eighteen infants received the medium level LC PUFA supplement vs 18 the control formula (gestational age (GA) 31.9+/- 1.8w, birthweight (BW) 1.73+/-0.44kg vs GA 31.6+/- 2.3w, BW 1.74+/- 0.30kg).
Interventions	The control formula contained 12.8% LA and 1.4% ALA. There were three supplemented formulae: low (0.32% AA & 0.24% DHA), medium (0.49% AA & 0.35% DHA) and high (1.1% AA & 0.76% DHA). The AA and DHA were obtained from single cell oils.
Outcomes	Fatty acids in erythrocyte membrane phospholipids, lymphocyte membrane phospholipids and plasma phospholipids were measured at 2 and 6 weeks. Anthropometric measurements were recorded at birth, and at 2 and 6 weeks of age. (6 week measurement/ 38 weeks PMA entered as term data)
Notes	The formula-fed group receiving the medium level of LCPUFA supplementation had erythrocyte fatty acids similar to the breast milk fed group and therefore are included as the comparison with controls for this review.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Unclear	Can't tell
Allocation concealment?	Yes	Blinding of randomisation: Yes
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Clandinin 2005

Methods	Infants were randomised, stratified by birthweight (< 1000g, 1000-1500g, >1500g), by computer-generated assignment schedules to receive control formula or one of two supplemented formulae. Interventions and assessors of outcomes were blinded. Follow-up was incomplete (50-60% for the primary outcome, 44-46% for neurodevelopment).
Participants	Preterm infants equal or less than 35 weeks were eligible if they had received < 10 days of enteral feedings > 30 ml/kg/day. Exclusion criteria: GI tract and liver abnormalities and/or disease including confirmed NEC, congenital abnormalities or diseases likely to interfere with evaluation. 361 infants were enrolled. BW (gestational age): Algal/fungal DHA group: 1189+-34g (29.4+-0.3 weeks), fish/fungal DHA group: 1107+-31g (28.8+-0.2 weeks), BW of the control group: 1215+-33g (29.6+-0.3 weeks). In addition, there was a non-randomised reference group of 105 breast fed term infants.
Interventions	Infants were fed preterm formula from enrolment until near discharge (24kcal/oz), discharge formula to 3m post-term (22kcal/oz), and term formula to 12m post-term (20kcal/oz). Each study group was provided with ready-to-use formulas, the only differences being the polyunsaturated fatty acid profiles due to absence of DHA and AA in control formula. There were two supplemented groups (algal/fungal oil or fish/fungal oil) and for the meta-analysis in this review, we chose the algal/fungal group because a) microbial oils are very similar to human milk fat and b) results of the trial suggested superiority of algal/fungal over fish/fungal oil for the primary outcome of the trial. The supplemented formulae contained either 17 mg/100 kcal algal DHA and 34 mg/100 kcal fungal AA or 17 mg/100 kcal fish DHA and 34 mg/100 kcal fungal AA. The preterm supplemented formulas contained 18.6% LA and 2.4% ALA, 0.33% algal DHA, 0.33% fungal DHA vs 18.7% LA and 2.4% ALA in the control formula.
Outcomes	Primary outcome was weight at 4m and 12m post-term. Secondary outcomes included several anthropometric measurements over the first 18m, neurodevelopment assessed by Bayley Scales of Infant Development (MDI, PDI) at 18m post-term, data on fluid intake, feeding tolerance and a range of blood tests (blood picture, cholesterol, glucose, tryglycerides, electrolytes and minerals, liver and kidney function tests), and adverse events.
Notes	Change of enrolment criteria during study. Initially infants > 1500g were included in the study. After an amendment of the protocol, only infants equal or less than 1500g were enrolled. Authors provided numerical data for growth and neurodevelopmental outcome (these appeared only in Figures in the publication) as well as methodological details. This study was sponsored by Mead Johnson Nutritionals, Indiana, USA, who also provided the study formulas.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes (computer-generated randomisation schedules)
Allocation concealment?	Yes	Blinding of randomisation: Yes (sealed envelopes) Stratification by birth weight
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	No	Follow-up incomplete: Primary outcome of weight at 4 m and 12 m post-term: 50-60% Neurodevelopment: 44-46%
Free of selective reporting?	Yes
Free of other bias?	Yes

Fadella 1996

Methods	Infants were randomised on day 10 to supplemented or control formula. Randomisation and intervention were not blinded. It is not stated whether assessment of outcome was blinded. Follow-up of subjects is complete.
Participants	Preterm AGA infants were included if >50% nutrition was enteral on day 10. Supplemented group; GA 31.1+-1.2 weeks, BW 1583+-310g, n=21. Control group; GA 31.3+-1.2 weeks, 1463+-273g, n=25.
Interventions	Supplemented formula LA 10.8-12.2%, ALA 0.40-0.73%, DHA 0.23%, AA 0.23%. Control formula LA18.6-19.4%, ALA 0.25-0.9%, DHA 0.01%, AA 0.02%.
Outcomes	At 52 weeks postconceptional age, flash visual evoked potentials (VEP), electroretinograms (ERG) and auditory responses were measured. Red blood cell (RBC) total fatty acids were also measured.
Notes	Sixty-six infants were enrolled, 17 of whom formed a breast milk fed reference group. The formula groups received up 25% milk as breast milk. Methodology of assessment for VEP and ERG deviate from international standards and therefore interpretation is difficult.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Unclear	Can't tell
Allocation concealment?	No	Blinding of randomisation: No
Blinding?	Unclear	Blinding of intervention: No Blinding of outcome measurement: Can't tell
Incomplete outcome data addressed?	Unclear	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	No	Formula groups received up to 25% of milk as breast milk Methodology of assessment of VEP and ERG deviate from international standards

Fang 2005

Methods	Infants were randomised by drawing lots, intervention was double blinded, assessors of outcomes were probably blinded, follow-up rate of neurodevelopmental assessment at 12m was 81-94%.
Participants	Preterm AGA 30-37 weeks were eligible if they had normal fundus oculi and not been started on oral feeds. 27 infants (intervention group: n=16, control group: n=11) were enrolled. Supplemented group BW 1980+/-110g, GA 33.3+/-0.5w. Control group BW 1990+/-120g, GA 33.0+/-0.5w. Exclusion criteria: Breastfeeding, maternal diabetes or drug abuse, sepsis, chronic lung disease, PVL, surgical NEC, administration of products containing DHA or AA, mechanical ventilation after introducing feeds, and various other conditions and diseases.
Interventions	Supplemented formula ("Neoangelac Plus") LA/ALA 10:1, DHA 0.05% and AA 0.1% from unicellular organisms. Control formula ("Neoangelac") LA/ALA 10:1, no added DHA/AA. Study formula was given from reaching 32 weeks postconceptional age and weight > 2000g for 6 months.
Outcomes	Outcomes included neurodevelopment at 6m and 12m post-term (Bayley Scales of Infant Development (MDI, PDI), anthropometric measurements at 1,2,3,4,5,6,12m, and visual acuity by steady state VEP, Lea grating cards, and Hiding Heidi low contrast cards at 4 and 6m after enrolment.
Notes	Initially the authors planned to enrol 30 infants in each group, but because of increase in breastfeeding, strict exclusion criteria and an outbreak of SARS the number of included subject was lower. Study formula was provided by Multipower Enterprise Corporation.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Probably adequate (drawing lots)
Allocation concealment?	Unclear	Blinding of randomisation: Can't tell
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up rate of primary outcome 81-94%
Free of selective reporting?	Yes
Free of other bias?	Yes

Fewtrell 2002

Methods	Infants were randomised, double-blind, stratified by birthweight (< & > 1200g), centre-wise in permuted blocks by independent personnel to receive supplemented or control formula. Assessment was blinded and follow up was complete.
Participants	Preterm infants (n=195) from three centres were included if BW <1750g and fully formula fed by 10 days, and no congenital malformations. Supplemented group BW 1336+/-284g, GA 30.4+/-2.3w. Control group BW 1353+/-274g, GA 30.3+/-2.4w.
Interventions	Control preterm formula contained 10.6 % fa LA and 0.7% fa ALA. Supplemented preterm formula contained 0.17% fa DHA, 0.31% fa AA and 0.04% fa EPA. Trial formula was fed for a mean+/-SD of 33+/-17 days.
Outcomes	Primary outcome was neurodevelopment at 18m post-term. Bayley Scales of Infant Development (MDI, PDI) at 18 months post-term. Knoblock, Passamanik & Sherrard's Developmental Screening Inventory at 9 m post-term. Neurological impairment at 9 and 18 m post-term. Growth in hospital and at 9 and 18 m post-term.
Notes	Funded by Numico Research BV (Wageningen, The Netherlands).

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes
Allocation concealment?	Yes	Blinding of randomisation: Yes Stratification by birth weight
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Fewtrell 2004

Methods	Infants were randomised, double-blind, stratified by birthweight (< & > 1200g), centre-wise in permuted blocks by independent personnel to receive supplemented or control formula. Outcome assessors were blinded and follow up rate for the primary outcome was 87% and 80% in treatment and control group respectively.
Participants	Preterm infants (n=238) from five UK centres were included if BW equal or less than 2000g and < 35 weeks gestation if they received at least some of their enteral feeds as formula milk. They were enrolled when the attending paediatrician decided that infant formula should be started. Age at randomisation: Supplemented group 14.3+-9.6 days. Control group 13.9+-10.4 days. Supplemented group BW 1487+/-342g, GA 31.2+/-2.1w. Control group BW 1510+/-326g, GA 31.1+/-1.9w. Exclusion criteria: Congenital abnormalities known to affect growth or neurodevelopment.
Interventions	Infants were fed preterm formula until the infant reached 2 kg or was discharged. After this point, post-discharge (nutrient-enriched) formula was given. Control preterm formula contained 11.5 % LA and 1.6 % ALA. Supplemented preterm formula contained 12.3 % LA, 1.5 % ALA, 0.5 % DHA, 0.9% C18:3 n-6 gamma-LA, 0.04 % AA and 0.1 % EPA (borage/fish oil) . Formula was given from enrolment to 9m post term.
Outcomes	Primary outcome was neurodevelopment at 18m post-term. Bayley Scales of Infant Development (MDI, PDI) at 18 months post-term. Knoblock, Passamanik & Sherrard's Developmental Screening Inventory at 9 m post-term. Neurological impairment at 9 and 18 m post-term. Growth in hospital and at 9 and 18 m post-term. Adverse events.
Notes	Supported by a grant from H. J. Heinz Company who also provided the study formulas.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes
Allocation concealment?	Yes	Blinding of randomisation: Yes Stratification by birth weight
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up rate of primary outcome 80-87%
Free of selective reporting?	Yes
Free of other bias?	Yes

Groh-Wargo 2005

Methods	Infants were randomised, double-blind, to 3 groups based on gender and stratified by birth weight (750-1250g/1251-1800g) in permuted blocks to receive supplemented or control formula. Intervention was blinded. Outcome assessors were blinded. Follow-up rate of anthropometrics at 4m was 92% and 77% in treatment and control group respectively. Follow-up rate at 12m was 77% in both treatment and control group.
Participants	40 infants <33w gestation and between 750-1800g birth weight and < 28 d (control n=13, fungal/fish n=13, egg-TG/fish N=14). Supplemented groups: fungal/fish: BW 1424+/-331g, GA 30.6+/-2.5w. egg/fish: BW 1367+/-242g, GA 30.4+/-2.1w. Control group BW 1322+/-270g, GA 30.0+/-2.3w. Exclusions include serious congenital malformations, major surgery, asphyxia, PVL and IVH>grade 2 and serious systemic infection.
Interventions	Infants were fed preterm formula until term corrected age then post-discharge nutrient-enriched formula until 12 m post-term. There were two supplemented groups (fungal/fish oil or egg-TG/fish oil) and, for this meta-analysis and review, we chose the fungal/fish group as microbial oils are more similar to human milk fat than egg-TG. Supplemented formula contained 0.42% AA and 0.27% DHA until term, and then 0.42% AA and 0.16% DHA until 12 m. Control formula contained 16-19% LA and 2.5% ALA. Infants in all groups also received human milk, for example at term, 33% control and 50% supplemented infants consumed human milk at least once per day.
Outcomes	Primary outcome was body composition as measured by absorptiometric x-ray techniques (DEXA) at 4m post-term. Other outcomes included body composition and anthropometrics at 35w and 40w corrected age, 4m and 12m post-term. Biochemical outcomes included blood fatty acid profiles.
Notes	Twenty of the sixty participants of this study are already included in the multicentre trial O'Connor 2001. The authors clarified methodological details and provided anthropometric raw data of the 40 infants who were not included in O'Connor 2001. The study was supported by a grant from Ross Products Division, Abbott Laboratories.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes
Allocation concealment?	Yes	Blinding of randomisation: Yes Stratification by gender and birth weight
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Unclear	Follow-up rate of primary outcome of body composition at 4 m post-term: 77-92% Follow-up rate at 12 m post-term: 77%
Free of selective reporting?	Yes
Free of other bias?	Yes

Hansen 1997

Methods	Infants were randomised to receive control formula or one of two supplemented formulae. It is unclear whether assessment was blinded or whether follow up was complete.
Participants	Preterm infants (n=194) with BW 0.86 - 1.56kg.
Interventions	The supplemented formulae contained either 0.15% algal DHA or 0.14% algal DHA and 0.27% fungal AA. The LA:ALA ratio of the control formula is not available.
Outcomes	Anthropometric measurements and visual acuity (Teller acuity cards) were recorded at 2 and 4 months postconceptional age.
Notes	Abstract only is available. The formula supplemented with DHA and AA was compared with control formula for this review. There was a breast milk fed reference group (n=80). 194 infants were randomised. An assumption was made for this review that there were 64 per group.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Unclear	Can't tell
Allocation concealment?	Unclear	Can't tell
Blinding?	Unclear	Can't tell
Incomplete outcome data addressed?	Unclear	Can't tell
Free of selective reporting?	Unclear	Can't tell
Free of other bias?	Unclear	Can't tell

Innis 2002

Methods	Double-blind prospective randomised trial (blinding of assessment unclear). Infants randomised to one of three formula by computer-generated randomisation schedules. Two different codes were used for each of the formulas to ensure blinding. Follow up was complete.
Participants	194 healthy preterm infants BW 846-1560g. Exclusion - SGA, >24 days of age when full enteral feeds tolerated, nec or other GI disease, impaired vision, disease/congenital malformation that may impair growth. Supplemented GA 29.7+/-1.7g, BW 1.28+/-0.18w, n=66. Control GA 29.5+/-1.7w, BW 1.23+/-0.18g, n=62.
Interventions	There were three preterm formulas: control (21-22% LA, 3- 3.1%ALA); two supplemented (0.34% DHA from DHA enriched oil, or 0.33% DHA and 0.60% AA from algal/fungal oils, neither had EPA). For this meta-analysis and review, we chose the supplement with DHA and AA. Formulas were fed from when 50kcal/kg/d was tolerated, for at least 28 days until discharge. Term formula without DHA and AA was fed after discharge.
Outcomes	RBC fatty acids at discharge and 48w PMA. Anthropometrics at 40, 48 and 57w PMA. Visual acuity (Teller acuity cards) at 48 and 57w PMA.
Notes	Sponsored by Mead Johnson Nutritionals, Indiana.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes (computer-generated randomisation schedules)
Allocation concealment?	Unclear	Blinding of randomisation: Can't tell
Blinding?	Unclear	Blinding of intervention: Yes Blinding of outcome measurement: Can't tell
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Lapillonne 2000

Methods	Infants were randomised, double-blind, to 2 groups to receive supplemented or control formula. Allocation was concealed using sealed opaque envelopes. Intervention was blinded. Outcome assessors were blinded. Follow-up rate of anthropometrics at 3 m and 6 m post term was 100%.
Participants	Twenty three healthy preterm infants, BW 700-1500 g. Exclusion - major neonatal morbidity (e.g. congenital malformations, respiratory treatment for more than 10 d, congenital infection, necrotizing enterocolitis, bowel resection), postnatal age >21 d, supplemental oxygen, or treatments that could influence growth and development (e.g. diuretics or corticosteroids), failure to achieve full enteral feeds (150 ml/kg/d) by 21 d of life, maternal history of substance abuse, diabetes, hyperlipidaemia, or abnormal dietary patterns (strict vegetarian diet). Supplemented GA 29.4+/-1.4 w, BW 1.28+/-0.17 kg, n=11. Control GA 29.7+/-1.7 w, BW 1.24 +/-0.16 kg, n=12.
Interventions	Enteral feeding of all infants was started during the first week of life using pooled, pasturized breast milk. Formula feeding began during the first 3 weeks of life if mothers had decided not to breast feed. Infants were fed preterm formula from enrolment until term corrected age. After this point, term formula was given until 4 m post term. Control preterm formula contained 18.0 % LA and 1.6 % ALA. Supplemented preterm formula contained 17.8 % LA, 1.1 % ALA, 0.37 % DHA, 0.02 % AA and 0.05 % EPA (LCPUFA from fish oil).
Outcomes	RBC fatty acids and anthropometrics at enrolment, discharge, term corrected age, 3m and 6 post term. Primary outcome was RBC DHA content.
Notes	This study also reported on a non-randomised control group of breast fed infants (n=10) who are not subject of this review.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes
Allocation concealment?	Yes	Blinding of randomisation: Yes (sealed envelopes)
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

O'Connor 2001

Methods	Infants were randomised to 3 groups based on centre, gender, stratified 750-1250g/1251-1800 BW. Infants were enrolled from eight centres in UK and North America. It is assumed that the study was double -blind but this is not clearly stated. Assessment was blinded and follow up was complete.
Participants	470 infants <33w gestation and between 750-1805g birthweight and < d 28 age (control n=144, fungal/fish n=140, egg-TG/fish N=143, human milk exclusively n=43. Exclusions include serious congenital malformations, major surgery, asphyxia, PVL and IVH>grade 2 and serious systemic infection. Supplemented group BW 1305+/-293.
Interventions	Infants fed preterm formula until term corrected age then post-discharge (nutrient-enriched) formula until 12 m post-term. There were two supplemented groups (fish/fungal oil or egg-TG/fish oil) and, for this meta-analysis and review, we chose the fish/fungal group as microbial oils are more similar to human milk fat than egg-TG, and there were minimal differences between fish/fungal and egg-TG/fish groups. Supplemented formula contained 0.42% AA and 0.26% DHA until term, and then 0.42% AA and 0.16% DHA until 12 m. Control formula contained 16-19% LA and 2.5% ALA. Infants in all groups also received human milk, for example at term, 35% control and 28% supplemented infants consumed human milk at least once per day.
Outcomes	Primary outcome was Bayley Scales of Infant development at 12m. Visual acuity was assessed by Teller acuity cards at 2, 4 and 6 m corrected age, and by VEP in 2/8 centres at 4 and 6 m corrected age. Fagan test of Infant Intelligence was administered at 6 and 9 m corrected age. MacArthur Communicative Development Inventories was administered at 9 and 14 months corrected age. Growth was measured at term and 2,4,6,9 and 12 months.
Notes	Sponsored by Ross Products Division, Abbott Laboratories, Ohio. Authors contacted to provide data for growth and visual acuity, as these appear only in Figures in the publication.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes
Allocation concealment?	Yes	Blinding of randomisation: Yes Stratification by gender and birth weight
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Uauy 1990

Methods	Outcome assessment was blinded but it is not stated whether randomisation and intervention were blinded. Follow-up of subjects was complete.
Participants	Supplemented group GA 30.7+/-1.2w, BW 1281+/-101g. Control groups a) GA 30.9++/-1.6w, BW 1340+/-106g, b) GA 29.6+/-1.6w, BW 1224+/-92g.
Interventions	Infants were fed study formulae, on average, from day 10 to day 45. Infants were randomised to the supplemented group who received soy/marine oil (LA 20.4%, ALA 1.4%,n-6>C18 0.1%, n-3>C18 1.0%) or control group a) corn oil (LA 24.2%, ALA 0.5%) or control group b) soy oil (LA 20.8%, ALA 2.7%).
Outcomes	ERG at 36 w and 57 w postconceptional age (PCA). VEP acuity at 36 & 57 weeks PCA. FPL acuity at 57 weeks PCA. Lipid peroxidation products (TBARS) or thiobarbituric acid reactive substances expressed as -azide/+azide x 100%which normalises for individual variation, high % suggests a high capacity for lipid peroxidation). Infant bleeding times 57w PCA. RBC membrane fluidity at 25 and 37 degrees. Growth at 40w, 48w and 57w PCA.
Notes	For the purpose of this analysis, control group b) was used as the LA:ALA ratio is most similar to other studies and current commercial formula.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Unclear	Can't tell
Allocation concealment?	Unclear	Blinding of randomisation: Can't tell
Blinding?	Yes	Blinding of intervention: Can't tell Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

van Wezel 2002

Methods	Double blind study with complete follow up. Infants were randomised using computer-generated random list and applied by an independent research officer. Assessment was blinded and follow up was complete.
Participants	Preterm infants (<34 weeks GA and <1750g). Supplemented group BW 1.282+/-0.316kg, GA 30.4+/-1.5wk, n=22. Control group BW 1.30+/-0.257g, GA 30.4+/-1.6wk , n=20. Inclusion criteria - normal neurological examination and cerebral ultrasounds. Exclusion criteria - significant cerebral damage, retinopathy, chronic disease or feeding problems.
Interventions	Supplemented preterm and term formula contained 0.34% DHA and 0.68% AA from micro algae . LA and ALA levels are not given. Preterm formula was fed until a weight of 3kg. Infants then received a term formula with or without supplement as per randomisation until 6 m corrected age.
Outcomes	Cerebral myelination assessed by magnetic resonance imaging (MRI). Bayley Scales of Infant Development (MDI, PDI), Visual acuity by flash VEP and Teller cards, RBC and plasma fatty acids.
Notes	Sponsored by Nutricia, Numico Research.

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes (computer-generated randomisation schedules)
Allocation concealment?	Yes	Blinding of randomisation: Yes
Blinding?	Yes	Blinding of intervention: Yes Blinding of outcome measurement: Yes
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Vanderhoof 1999

Methods	Randomisation computerised and stratified by BW (750-1000, 1001-1500, 1501-2000). Blinding by coded labels and verified by "trained sensory panel". It is unclear whether assessment was blinded. Follow up was complete.
Participants	Supplemented group BW 1522+/-370g, GA 31.0+/-2.5wks, n=77. Control group BW 1484+/-365, GA 30.8+/-2.7, n=78. Inclusion criteria - preterm bw 750-2000g, 0-28 da of age, medically stable, received enteral feeds for < 24 hrs, AGA. Exclusion criteria - significant acute/chronic illness, systemic infections, major congenital malformations, IVH>grade 2, PVL, seizures. Withdrawal criteria - if bw>1000g and full enteral feeds not attained by d 28; if bw 750-1000 and full enteral feeds not attained by d 42; for all infants, if unable to tolerate full enteral feeds., or need for mechanical ventilation after full enteral feeds attained; or oxygen dependency at 36w PCA, and/or >5d course steroids. Infants enrolled from 16 sites.
Interventions	Supplemented preterm formula LA 12.1% fa, ALA 1.5% fa, AA 0.50% fa and DHA 0.35% (LCPUFA from single cell oil source). Control preterm formula LA 12.8% fa, ALA 1.4% fa, AA and DHA 0%. Infants were fed one of two preterm formulas, with or without LCPUFA, until 48 weeks PCA . All infants were then fed a standard term formula (unsupplemented) until 92 weeks PCA.
Outcomes	Anthropometrics, adverse events and plasma fatty acids were measured to 92 weeks PCA.
Notes	Sponsored by Wyeth Nutritionals International, Philadelphia, Pennsylvania, USA

Risk of bias table

Item	Judgement	Description
Adequate sequence generation?	Yes	Yes (computer-generated randomisation schedules)
Allocation concealment?	Yes	Blinding of randomisation: Yes (coded labels) Stratification by birth weight
Blinding?	Unclear	Blinding of intervention: Yes Blinding of outcome measurement: Can't tell
Incomplete outcome data addressed?	Yes	Follow-up complete
Free of selective reporting?	Yes
Free of other bias?	Yes

Characteristics of excluded studies

Donzelli 1996

Reason for exclusion	Published data were inadequate to assess this study.

Koletzko 2003

Reason for exclusion	This randomised study measured anthropometric data and fatty acid profiles within the study period of 28 days. The study was excluded because there were no follow-up data beyond 28 days.

Lim 2002

Reason for exclusion	Published data were inadequate to assess this study.

Rodriguez 2003

Reason for exclusion	This trial compared LCPUFA supplemented formula with breast feeding and was not randomised.

References to studies

Included studies

Carlson 1992

Published and unpublished data

Carlson SE, Cooke RJ, Rhodes PG, Peeples JM, Werkman SH, Tolley EA. Longterm feeding of formulas high in LA and marine oil to VLBW infants: phospholipid fatty acids. Pediatric Research 1991;30:404-12.

* Carlson SE, Cooke RJ, Werkman SH, Tolley EA. First year growth of infants fed standard formula compared with marine oil supplemented formula. Lipids 1992;27:901-7.

Carlson SE, Werkman SH, Peeples JM, Cooke RJ, Tolley EA. Arachidonic acid correlates with first year growth in preterm infants. Proceedings of the National Academy of Sciences 1993;90:1073-7.

Carlson SE, Werkman SH, Rhodes PG, Tolley EA. Visual acuity development in healthy preterm infants: effect of marine oil supplementation. American Journal of Clinical Nutrition 1993;58:35-42.

Carlson SE. Lipid requirements of VLBW infants for optimal growth and development. In: Lipids, Learning and the Brain: Fats in infant formula. Report of the 103rd Ross Conference on Pediatric Research. Columbus, Ohio: Ross Labs, 1993.

Werkman SH, Carlson SE. A randomised trial of visual attention of preterm infants fed DHA until 9 months. Lipids 1996;31:91-7.

Carlson 1996

* Carlson SE, Werkman SH, Tolley EA. Effect of long chain n-3 fatty acid supplementation on visual acuity and growth of preterm infants with and without bronchopulmonary dysplasia. American Journal of Clinical Nutrition 1996;63:687-97.

Carlson SE, Werkman SH. A randomised trial of visual attention of preterm infants fed DHA until 2 months. Lipids 1996;31:85-90.

Carnielli 2007

Carnielli VP, Simonato M, Verlato G, Luijendijk I, De Curtis M, Sauer PJJ, et al. Synthesis of long-chain polyunsaturated fatty acids in preterm newborns fed formula with long-chain polyunsaturated fatty acids. The American Journal of Clinical Nutrition 2007;86:1323-30.

Clandinin 1997

Clandinin MT, Van Aerde JE, Parrott A, Field CJ, Euler AR, Lien EL. Assessment of the efficacious dose of arachidonic and docosahexaenoic acids in preterm infant formulas: fatty acid composition of erythrocyte membrane lipids. Pediatric Research 1997;42:819-25.

Clandinin 2005

Clandinin MT, Van Aerde JE, Merkel KL, Harris CL, Springer MA, Hansen JW, Diersen-Schade DA. Growth and development of preterm infants fed infant formulas containing docosahexaenoic acid and arachidonic acid. The Journal of Pediatrics 2005;146:461-8.

Fadella 1996

Fadella G, Giovani M, Alessandroni R et al. Visual evoked potentials and dietary LCPUFA in preterm infants. Archives of Disease in Childhood 1996;75:F108-12.

Fang 2005

Fang PC, Kuo HK, Huang CB, Ko TY, Chen CC, Chung MY. The effect of supplementation of docosahexaenoic acid and arachidonic acid on visual acuity and neurodevelopment in larger preterm infants. Chang Gung Medical Journal 2005;28:708-15.

Fewtrell 2002

Fewtrell MS, Morley R, Abbott RA, Singhal A, Isaacs EB, Stephenson T, MacFayden U, Lucas A. Double-blind, randomised trial of long-chain polyunsaturated fatty acids in formula fed to preterm infants.. Pediatrics 2002;110:73-82.

Fewtrell 2004

Fewtrell MS, Abbott RA, Kennedy K, Singhal A, Morley R, Caine E, Jamieson C, Cockburn F, Lucas, A. Randomized, double-blind trial of long-chain polyunsaturated fatty acid supplementation with fish oil and borage oil in preterm infants. The Journal of Pediatrics 2004;144:471-9.

Groh-Wargo 2005

Groh-Wargo S, Jacobs J, Auestad N, O'Connor DL, Moore JJ, Lerner E. Body composition in preterm infants who are fed long-chain polyunsaturated fatty acids: A prospective, randomized, controlled trial. Pediatric Research 2005;57:712-8.

Hansen 1997

Hansen J, Schape D et al. Docosahexaenoic acid plus arachidonic acid enhance preterm infant growth. In: Essential Fatty Acids & Eicosanoids. Edinburgh, 1997:T16.

Innis 2002

Innis SM, Adamkin DH, Hall RT, Kalhan SC, Lair C, Lim M et al. Docosahexanoic acid and arachidonic acid enhance growth with no adverse effects in preterm infants fed formula. Journal of Pediatrics 2002;140:547-54.

Lapillonne 2000

Lapillonne A, Picaud JC, Chirouze V, Goudable J, Reygrobellet B, Claris O, et al. The use of low-EPA fish oil for long-chain polyunsaturated fatty acid supplementation of preterm infants. Pediatric Research 2000;48:835-41.

O'Connor 2001

O'Connor DL, Hall R, Adamkin D, Austead N, Castillo M, Connor WE et al. Growth and development in preterm infants fed longchain polyunsaturated fatty acids: A prospective randomised trial.. Pediatrics Aug 2001;108:359-71.

Uauy 1990

Birch DG, Birch EE, Hoffman DR, Uauy RD. Retinal development of very low birthweight infants fed diets differing in n-3 fatty acids. Investigative Ophthalmology & Visual Science 1992;33:2365-76.

Hoffman DR, Uauy R. Essentiality of dietary n-3 fatty acids for premature infants; plasma and red blood cell fatty acid composition. Lipids 1992;27:886-95.

Uauy R, Hoffman DR, Birch EE, Birch DG, Jameson DM, Tyson J. Safety and efficacy of n-3 fatty acids in the nutrition of very low birthweight infants: soy oil and marine oil supplementation of formula. Journal of Pediatrics 1994;124:612-20.

* Uauy RD, Birch DG, Birch EE, Tyson JE, Hoffman DR. Effect of dietary omega 3 fatty acids on retinal function of very low birthweight neonates. Pediatric Research 1990;28:485-92.

van Wezel 2002

van Wezel-Meijler G, van der Knaap MS, Huisman J, Jonkman EJ, Valk J, Lafeber HN. Dietary supplementation of long-chain polyunsaturated fatty acids in preterm infants: effects on cerebral maturation.. Acta Paediatrica 2002;91(9):942-50.

Vanderhoof 1999

* Vanderhoof J, Gross S, Hegyi T, Clandinin T, Porcelli P, DeCristofaro J, Rhodes T, Tsang R, Shattuck K, Cowett R, Adamkin D, McCarton C, Heird W, Hook-Morris B, Pereira G, Chan G, Van Aerde J, Boyle F, Pramuk K, Euler A, Lien EL. Evaluation of a long-chain polyunsaturated fatty acid supplemented formula on growth, tolerance, and plasma lipids in preterm infants up to 48 weeks postconceptional age. Journal of Pediatric Gastroenterology and Nutrition 1999;29:318-26.

Vanderhoof J, Gross S, Hegyi T. A multicenter long-term safety and efficacy trial of preterm formula supplemented with long-chain polyunsaturated fatty acids. Journal of Pediatric Gastroenterology and Nutrition 2000;31:121-7.

Excluded studies

Donzelli 1996

Donzelli GP, Cafaggi L, Rapisardi G, Moroni M, Pratesi S. Longchain polyunsaturated fatty acids and early neural and visual development in preterm infants. Pediatric Research 1996;40:527.

Koletzko 2003

Koletzko B, Sauerwald U, Keicher U, Saule H, Wawatschek S, Boehles H, Bervoets K, Fleith M, Crozier-Willi G. Fatty acid profiles, antioxidant status, and growth of preterm infants fed diets without or with long-chain polyunsaturated fatty acids - a randomized clinical trial. European Journal of Nutrition 2003;42:243-53.

Lim 2002

Lim M, Antonson D, Clandinin M, vanAerde J, Green D, Stevens K et al. Formulas with DHA and ARA for LBW infants are safe. Pediatric Research 2002;51:319A.

Rodriguez 2003

Rodriguez A, Raederstorff D, Sarda P, Lauret C, Mendy F, Descomps B. Preterm infant formula supplementation with alpha linoleic acid and docosahexaenoic acid. European Journal of Clinical Nutrition 2003;57:727-34.

Studies awaiting classification

Ongoing studies

Other references

Additional references

Anderson 1999

Anderson JW, Johnstone BM, Remley DT. Breast-feeding and cognitive development: a meta-analysis. The American Journal of Clinical Nutrition 1999;70:525-35.

Bjerve 1992

Bjerve KS, Bredde OL, Bonaa K, Johnson H, Vatten L, Vik T. Clinical and epidemiological studies with alpha linolenic acid and longchain n-3 fatty acids. In: Sinclair AJ, Gibson RA, editor(s). Third International Conference on Essential Fatty Acids and Eicosanoids. Illinois: AOCS, March 1992.

Clandinin 1980

Clandinin MT, Chappell JE, Leong S, Heim T, Swyer PR, Chance GW. Intrauterine fatty acid secretion rates in human brain: implications for fatty acid requirements. Early Human Development 1980;4:121-9.

Clark 1992

Clark KJ, Makrides M, Neumann MA, Gibson RA. Determination of the optimal ratio of linoleic acid to alpha linolenic acid in infant formulas. Journal of Pediatrics 1992;120:S151-8.

Fagan 1970

Fagan JF. Memory in the infant. Journal of Experimental Child Psychology 1970;9:217-26.

Fagan 1983

Fagan JF, Singer LT. Infant recognition memory as a measure of intelligence. In: Lipsitt LP, editor(s). Advances in Infant Research. Vol. 2. Ablex, Norwood, 1983:31-72.

Henriksen 2008

Henriksen C, Haugholt K, Lindgren M, Aurvåg AK, Rønnestad A, Grønn M, et al. Improved cognitive development among preterm infants attributable to early supplementation of human milk with docosahexaenoic acid and arachidonic acid. Pediatrics 2008;121:1137-45.

Kramer 2008

Kramer MS, Aboud F, Mironova E, Vanilovich I, Platt RW, Matush L, et al. Breastfeeding and child cognitive development: new evidence from a large randomized trial. Archives of General Psychiatry 2008;65:578-84.

Lucas 1992

Lucas A, Morley R, Cole TJ, Lister G, Leeson-Payne C. Breastmilk and subsequent intelligence quotient in children born preterm. Lancet 1992;339:261-4.

Makrides 1993

Makrides M, Simmer K, Goggin M, Gibson RA. Erythrocyte docosahexaenoic acid correlates with the visual response of the healthy, term infant. Pediatric Research 1993;33:3242-53.

Makrides 2009

Makrides M, Gibson RA, McPhee AJ, Collins CT, Davis PG, Doyle LW, et al. Neurodevelopmental outcomes of preterm infants fed high-dose docosahexaenoic acid: a randomized controlled trial. JAMA: The Journal of the American Medical Association 2009;301:175-82.

Morrow-Tlucak 1988

Morrow-Tlucak M, Haude RH, Ernhart CB. Breastfeeding and cognitive development in the first two years of life. Social Science & Medicine 1988;26:635-9.

Neuringer 1986

Neuringer M, Connor WE, Lin DS, Barstad L, Luck S. Biochemical and functional effects of prenatal and postnatal n-3 fatty acids on retina and brain in rhesus monkeys. Proceedings of the National Academy of Sciences USA 1986;83:4021-5.

Other published versions of this review

Simmer 2000

Simmer K. Longchain polyunsaturated fatty acid supplementation in preterm infants. Cochrane Database of Systematic Reviews 2000, Issue 2. Art. No.: CD000375. DOI: 10.1002/14651858.CD000375.

Simmer 2004

Simmer K, Patole S. Longchain polyunsaturated fatty acid supplementation in preterm infants. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD000375. DOI: 10.1002/14651858.CD000375.pub2.

Simmer 2008

Simmer K, Schulzke S2, Patole S. Longchain polyunsaturated fatty acid supplementation in preterm infants. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD000375. DOI: 10.1002/14651858.CD000375.pub3.

Outcome or Subgroup	Studies	Participants	Statistical Method	Effect Estimate
1.1 Visual acuity (log cycles/degree) at term	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.1.1 no BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.1.2 BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.2 Visual acuity (log cycles/degree) at 2m post-term	3		Mean Difference (IV, Fixed, 95% CI)	No totals
1.2.1 no BPD	3		Mean Difference (IV, Fixed, 95% CI)	No totals
1.2.2 BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.3 Visual acuity (log cycles/ degree) at 4m post-term	3		Mean Difference (IV, Fixed, 95% CI)	No totals
1.3.1 no BPD	3		Mean Difference (IV, Fixed, 95% CI)	No totals
1.3.2 BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.4 Visual acuity (log cycles /degree) at 6m post-term	2		Mean Difference (IV, Fixed, 95% CI)	No totals
1.4.1 no BPD	2		Mean Difference (IV, Fixed, 95% CI)	No totals
1.4.2 BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.5 Visual acuity (log cycles/degree) at 9m post-term	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.5.1 no BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.5.2 BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.6 Visual acuity (log cycles/degree) at 12m post-term	2		Mean Difference (IV, Fixed, 95% CI)	No totals
1.6.1 no BPD	2		Mean Difference (IV, Fixed, 95% CI)	No totals
1.6.2 BPD	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.7 Rod ERG at 36w PCA	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.7.1 log threshold (scot td-sec)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.7.2 log Vmax (uV)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.8 ERG at 3m post-term, amplitude(uV)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.9 Rod ERG at 4m post-term	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.9.1 log threshold (scot td-sec)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.9.2 log Vmax (uV)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.10 VEP at 3m post-term	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.10.1 N4 latency (millisec)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.10.2 P4 latency (millisec)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.11 Fagan infant test at 12m post-term	2		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.11.1 novelty time (% total time)	2	84	Mean Difference (IV, Fixed, 95% CI)	-4.11 [-7.47, -0.76]
1.11.2 total looks (n)	2	84	Mean Difference (IV, Fixed, 95% CI)	5.52 [2.16, 8.87]
1.11.3 time/look (sec)	2	84	Mean Difference (IV, Fixed, 95% CI)	-0.09 [-0.21, 0.02]
1.12 Fagan infant test at 9m post-term (% total time)	2		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.12.1 novelty time (%)	2	232	Mean Difference (IV, Fixed, 95% CI)	0.42 [-1.40, 2.24]
1.12.2 total looks (n)	1	51	Mean Difference (IV, Fixed, 95% CI)	7.20 [2.49, 11.91]
1.12.3 time/look (sec)	1	51	Mean Difference (IV, Fixed, 95% CI)	-0.13 [-0.29, 0.03]
1.13 Bayley MDI at 12m post-term	4	364	Mean Difference (IV, Fixed, 95% CI)	0.96 [-1.42, 3.34]
1.14 Bayley PDI at 12m post-term	4	353	Mean Difference (IV, Fixed, 95% CI)	0.23 [-2.77, 3.22]
1.15 Weight at 6w post-term (kg)	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.16 Length at 6w post-term (cm)	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.17 Head circumference at 6w post-term (cm)	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
1.18 Weight at term (kg)	4	296	Mean Difference (IV, Fixed, 95% CI)	0.05 [-0.07, 0.16]
1.19 Length at term (cm)	4	295	Mean Difference (IV, Fixed, 95% CI)	0.34 [-0.27, 0.96]
1.20 Head circ at term (cm)	3	185	Mean Difference (IV, Fixed, 95% CI)	0.18 [-0.26, 0.62]
1.21 Weight at 2m post-term (kg)	5	485	Mean Difference (IV, Fixed, 95% CI)	0.21 [0.08, 0.33]
1.22 Length at 2m post-term (cm)	4	297	Mean Difference (IV, Fixed, 95% CI)	0.47 [0.00, 0.94]
1.23 Head circumference at 2m post-term (cm)	3	187	Mean Difference (IV, Fixed, 95% CI)	0.03 [-0.33, 0.38]
1.24 Growth rate until 3m post-term	1	138	Mean Difference (IV, Fixed, 95% CI)	-0.00 [-0.04, 0.04]
1.24.1 weight g/d	1	46	Mean Difference (IV, Fixed, 95% CI)	-0.60 [-3.56, 2.36]
1.24.2 length cm/w	1	46	Mean Difference (IV, Fixed, 95% CI)	0.00 [-0.06, 0.06]
1.24.3 head circumference cm/w	1	46	Mean Difference (IV, Fixed, 95% CI)	0.00 [-0.06, 0.06]
1.25 Weight at 4m post-term (kg)	6	489	Mean Difference (IV, Fixed, 95% CI)	0.14 [-0.01, 0.29]
1.26 Length at 4m post-term (cm)	5	299	Mean Difference (IV, Fixed, 95% CI)	0.31 [-0.22, 0.84]
1.27 Head circumference at 4m post-term (cm)	4	198	Mean Difference (IV, Fixed, 95% CI)	-0.09 [-0.48, 0.30]
1.28 Weight at 12m post-term (kg)	4	271	Mean Difference (IV, Fixed, 95% CI)	-0.10 [-0.31, 0.12]
1.29 Length at 12m post-term (cm)	4	271	Mean Difference (IV, Fixed, 95% CI)	0.25 [-0.33, 0.84]
1.30 Head circumference at 12m post-term (cm)	4	271	Mean Difference (IV, Fixed, 95% CI)	-0.15 [-0.53, 0.23]
1.31 Normalised weight at 12m post-term	2	116	Mean Difference (IV, Fixed, 95% CI)	-0.33 [-0.56, -0.09]
1.32 Normalised length at 12m post-term	2	116	Mean Difference (IV, Fixed, 95% CI)	0.03 [-0.16, 0.22]
1.33 Normalised head circumference at 12m post-term	2	116	Mean Difference (IV, Fixed, 95% CI)	-0.14 [-0.38, 0.10]
1.34 Lipid peroxidation (TBARS -azide/+azide x 100%), 4m post-term	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.35 RBC fragility (hemolysis with 8-10% H2O2) , 4m post-term	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.36 Infant bleeding time 4m post-term (ped device, min)	1		Mean Difference (IV, Fixed, 95% CI)	No totals
1.37 Bayley MDI at 18m post-term	3	494	Mean Difference (IV, Fixed, 95% CI)	2.40 [-0.33, 5.12]
1.38 Bayley PDI at 18 m post-term	3	496	Mean Difference (IV, Fixed, 95% CI)	0.74 [-1.90, 3.37]
1.39 KPS Developmental Screening Inventory at 9 m post-term (overall quotient)	1	158	Mean Difference (IV, Fixed, 95% CI)	1.50 [-1.70, 4.70]
1.40 Weight at 9 m post-term	2	374	Mean Difference (IV, Fixed, 95% CI)	-0.01 [-0.22, 0.21]
1.41 Length at 9 m post-term	2	374	Mean Difference (IV, Fixed, 95% CI)	0.02 [-0.58, 0.61]
1.42 Head circumference at 9 m post-term	2	374	Mean Difference (IV, Fixed, 95% CI)	-0.03 [-0.37, 0.30]
1.43 Normailsed weight at 9 m post-term	1	158	Mean Difference (IV, Fixed, 95% CI)	-0.35 [-0.72, 0.02]
1.44 Normalised length at 9 m post-term	1	158	Mean Difference (IV, Fixed, 95% CI)	-0.30 [-0.69, 0.09]
1.45 Normalised head circumference at 9 m post-term	1	158	Mean Difference (IV, Fixed, 95% CI)	-0.10 [-0.51, 0.31]
1.46 Weight at 18 m post-term	2	396	Mean Difference (IV, Fixed, 95% CI)	-0.14 [-0.39, 0.10]
1.47 Length at 18 m post-term	2	396	Mean Difference (IV, Fixed, 95% CI)	-0.28 [-0.91, 0.35]
1.48 Head circumference at 18 m post-term	2	396	Mean Difference (IV, Fixed, 95% CI)	-0.18 [-0.53, 0.18]
1.49 Normalised weight at 18 m post-term	1	158	Mean Difference (IV, Fixed, 95% CI)	-0.33 [-0.68, 0.02]
1.50 Normalised length at 18 m post-term	1	158	Mean Difference (IV, Fixed, 95% CI)	-0.44 [-0.80, -0.08]
1.51 Normalised head circumference at 18 m post-term	1	158	Mean Difference (IV, Fixed, 95% CI)	-0.10 [-0.52, 0.32]
1.52 Fagan Infant test at 6m post-term, novelty time (%total time)	1	187	Mean Difference (IV, Fixed, 95% CI)	-0.50 [-2.64, 1.64]
1.53 MacArthur Communicative Inventories at 14 months post-term	1	399	Mean Difference (IV, Fixed, 95% CI)	0.34 [-3.05, 3.72]
1.53.1 vocab comprehension scores	1	199	Mean Difference (IV, Fixed, 95% CI)	1.70 [-2.96, 6.36]
1.53.2 vocab production scores	1	200	Mean Difference (IV, Fixed, 95% CI)	-1.20 [-6.14, 3.74]
1.54 Bayley MDI at 24 months post-term	1	42	Mean Difference (IV, Fixed, 95% CI)	4.20 [-7.96, 16.36]
1.55 Bayley PDI at 24 months post-term	1	42	Mean Difference (IV, Fixed, 95% CI)	-3.60 [-12.11, 4.91]

Longchain polyunsaturated fatty acid supplementation in preterm infants

Authors

Contact person

Sven M Schulzke

Dates

What's new

History

Abstract

Background

Objectives

Search methods

Selection criteria

Data collection and analysis

Results

Authors' conclusions

Plain language summary

Longchain polyunsaturated fatty acid supplementation in preterm infants

Background

Description of the condition

Description of the intervention

How the intervention might work

Why it is important to do this review

Objectives

Methods

Criteria for considering studies for this review

Types of studies

Types of participants

Types of interventions

Types of outcome measures

Search methods for identification of studies

Data collection and analysis

Selection of studies

Data extraction and management

Assessment of risk of bias in included studies

Measures of treatment effect

Assessment of heterogeneity

Data synthesis

Subgroup analysis and investigation of heterogeneity

Results

Description of studies

Risk of bias in included studies

Effects of interventions

Discussion

Authors' conclusions

Implications for practice

Implications for research

Acknowledgements

Contributions of authors

Declarations of interest

Differences between protocol and review

Published notes

Characteristics of studies

Characteristics of included studies

Carlson 1992

Risk of bias table

Carlson 1996

Risk of bias table

Carnielli 2007

Risk of bias table

Clandinin 1997

Risk of bias table

Clandinin 2005

Risk of bias table

Fadella 1996

Risk of bias table

Fang 2005

Risk of bias table

Fewtrell 2002

Risk of bias table

Fewtrell 2004

Risk of bias table

Groh-Wargo 2005

Risk of bias table

Hansen 1997

Risk of bias table

Innis 2002

Risk of bias table

Lapillonne 2000

Risk of bias table

O'Connor 2001