The National Longitudinal Study of Adolescent Health (Add Health) is a survey designed to measure the effects of family, peer group, school, neighborhood, religious institution, and community influences on behaviors that promote good health, such as seat belt use, exercise, and nutrition, as well as on health risks such as tobacco use, sexual activity, sun exposure, and drug and alcohol use. The study was undertaken in response to a mandate by the U.S. Congress in the NIH Revitalization Act of 1993 (Public Law 103-43, Title X, Subtitle D, Section 1031).
The main premise of the Add Health study is that social context--such as relationships with families, friends, and peers--influences the health-related behaviors of young people, and that understanding that context is essential to guide efforts to modify health behaviors.
The survey was conducted in two phases. In the first phase, roughly 90,000 students from grades 7 through 12 at 145 schools around the U.S. answered brief questionnaires to provide information about themselves and other aspects of their lives, including their health, friendships, self esteem, and expectations for the future. Parental support for the in-school survey was strong. Before students could participate, parents had to give their permission through procedures approved by each school. In some schools, parents volunteered their time to help administer the questionnaire.
In the second phase of the study, interviews were conducted with roughly 20,000 students and their parents in the students' homes. The National Opinion Research Center at the University of Chicago trained about 500 interviewers to carry out these interviews in communities across the country. With the written consent of both the adolescents and their parent, interviewers conducted a 90 minute computer-administered interview covering each adolescent's health and health behaviors, family life, peer relationships, goals and aspirations, and related topics. They also interviewed parents about the adolescents' health, family relationships, family income and health insurance, and parents' own health behavior.
One year later, these students were interviewed a second time in their homes. Because these adolescents were interviewed twice, it is possible to measure directly the influence of theirexperiences at one time on their later behaviors, and the consequences that such behaviors have on later outcomes.
One of the hallmarks of the Add Health study is the independent measurement of contextual influences on adolescent health. Administrators of participating schools have completed a short questionnaire about school characteristics that, along with the in-school student questionnaires, will provide comprehensive information on the school environment. In addition, investigators are using independent sources to compile a rich data set measuring health-related aspects of the local neighborhood and community. These will include measures of poverty, housing quality, attendance at churches or other religious institutions, unemployment rates, access to health services, public policies and expenditures, and much more. Information about peer groups was collected directly from peers, and information about home life was collected from parents and siblings. The large sample of siblings, twins, and adopted youth will allow an examination of how health behaviors vary within families, and how the same family may influence its children in different ways.
To ensure adequate samples of minority populations, the investigators collected information from large samples of Cuban, Puerto Rican, Chinese, and African American youth. The investigators also sampled disabled youth, to provide national data on the health and well-being of disabled adolescents.
The Add Health Principal Investigator is Dr. J. Richard Udry, Kenan Professor of Maternal and Child Health and of Sociology at the University of North Carolina at Chapel Hill. Other members of the project team include scientists at the University of Minnesota, the University of Arizona, the State University of New York--Albany, Battelle Institute, the University of North Carolina, and the National Opinion Research Center at the University of Chicago. A National Advisory Board includes scientists and adolescent health specialists from Northwestern University, the American Medical Association, the New Jersey Medical School, the University of Chicago, the University of Rochester Medical Center, and the University of Pennsylvania. The Advisory Board, along with scientists in fields related to adolescent health and scientists within the NIH and the Public Health Service, provided advice to the project team on the development of the study.
In addition to the National Institute of Child Health and Human Development, Federal offices and agencies supporting Add Health include: the National Cancer Institute, the National Institute of Alcohol Abuse and Alcoholism, the National Institute on Deafness and other Communication Disorders, the National Institute on Drug Abuse, the National Institute of General Medical Sciences, the National Institute of Mental Health, the National Institute of Nursing Research, the Office of AIDS Research (NIH), the Office of the Director (NIH), the Office of Research on Women's Health (NIH), the Office of Behavioral and Social Science Research (NIH), the Office of Population Affairs of the Department of Health and Human Services (DHHS), the National Center for Health Statistics of the Centers for Disease Control and Prevention (DHHS), Office of Minority Health of the Centers for Disease Control and Prevention (DHHS), the Office of Minority Health, Office of Public Health and Science (DHHS), the Office of the Assistant Secretary for Planning and Evaluation (DHHS), and the National Science Foundation. Many professional and scientific organizations have expressed their interest in the study, anticipating that the data and findings will have immense value for their own areas of research activities.
Project scientists are currently analyzing the data gathered from the first wave of the study and will release preliminary findings in September of 1997. This information was made available for other investigators to analyze in the Summer of 1997. The second wave of data is scheduled to be made public in November, 1997.