About – Add Health

About Add Health

Initiated in 1994, The National Longitudinal Study of Adolescent to Adult Health (Add Health) is the largest, most comprehensive nationally-representative longitudinal study of adolescents ever undertaken. Wave I included over 20,000 U.S. adolescents in grades 7-12 in the 1994-95 school year. Most recently, study participants were age 44, on average, during the Wave VI data collection effort. Wave VI of Add Health was primarily funded by the National Institute on Aging; earlier waves of Add Health were primarily funded by program project grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with co-funding from 23 other federal agencies and foundations.

Over the years, Add Health has collected rich demographic, social, familial, behavioral, psychosocial, cognitive, and health survey data from participants and their parents; a vast array of contextual data from participants’ schools, neighborhoods, and geographies of residence; and in-home physical and biological data from participants, including genetic markers, blood-based assays, anthropometric measures, and medications. Ancillary studies have added even more data over the years. Data from the project are available in various forms and have been analyzed in thousands of publications in peer-reviewed journals.

In addition to six waves of Add Health survey and biological data, Add Health investigators have also collected data on the parents of Add Health participants and a vast amount of ‘Omics data.

Core Add Health Data

Wave I took place between 1994 and 1995, during which 90,118 students from 145 middle, junior, and high schools completed a 45-minute questionnaire administrated in the school. Of the students who completed an in-school questionnaire, 20,745 adolescents were sampled to complete an in-home interview.

Question topics included health status and nutrition, peer networks, family composition and dynamics, sexual activity, substance use, criminal activities, and more.

Biological data were also collected, including height and weight. More information on Wave I and subsequent waves can be found in the Add Health User Guides.

During Wave II nearly 15,000 of the Wave I respondents were interviewed from April to August 1996, one year after the Wave I interview.

Participants who were in the 12th grade during Wave I or in the Wave I disabled sample were not sampled to participate in Wave II. The Wave II interview covered similar topics as the Wave I interview, with the addition of more detailed questions regarding nutrition and sun exposure.

More information on Wave II and other waves can be found in the Add Health User Guides.

Wave III was conducted from 2001 to 2002, interviewing 15,170 of the Wave I respondents. The questionnaire was designed to obtain relationship, marital, childbearing, and educational histories, and key labor force events. A sample of 1,507 partners of respondents was interviewed at Wave III, representing a wide spectrum of relationship intimacy and commitment.

Wave III collected residential latitude and longitude using a GPS device, along with high school transcript release forms. At Wave III, Add Health respondents provided saliva and urine specimens for HIV and STD testing. A subsample of full siblings and twins was also asked to provide a saliva sample for genetic analysis.

More information on Wave III and other waves can be found in the Add Health User Guides.

A fourth in-home interview was conducted in 2008 with 15,701 original Wave I respondents to study developmental and health trajectories across the life course of adolescence into young adulthood.

Survey questions were expanded to include educational transitions, economic status and financial resources and strains, sleep patterns and sleep quality, illnesses and medications, physical activities, memory, emotional content and quality of relationships, and maltreatment during childhood by caregivers. Additional indicators of interpersonal and occupational stressors, loneliness, and attitudes about parenting were included, along with expanded questions on substance addiction and dependency and items on intersections and balance between work and family responsibilities.

Geographic and biological data, including dried blood spots, were also collected.

More information on Wave IV and other waves can be found in the Add Health User Guides.

Wave V was conducted during 2016-2018 to collect social, environmental, behavioral, and biological data with which to track the emergence of chronic disease as the cohort advanced through their fourth decade of life.

The Wave V design included a mixed-mode survey. An in-home interview was administered to a sub-sample of respondents to analyze mode effects. Repeat anthropometric, cardiovascular, metabolic, and inflammatory measures indicative of the change in and/or onset of chronic disease, including obesity, hypertension, diabetes, and dyslipidemia were collected, along with new biomarkers of chronic kidney disease.

The survey was expanded to obtain retrospective reports of birth and childhood circumstances to supplement existing early life data.

More information on Wave V and other waves can be found in the Add Health User Guides.

The overall goal of Wave VI was to better understand life course trajectories, determinants, and consequences of critical dimensions of aging, health, and health disparities among U.S. early midlife adults. Participants were between the ages of 39 and 51, with an average age of 44. A total of 11,979 participants completed the Wave VI survey, which took place between 2022 and 2025.

Beyond longitudinal survey measures, newly added questions included those on cumulative stress, discrimination, despair, work-life balance, memory, physical limitations, and caregiving. Wave VI also included four domains of the Test My Brain cognitive assessments. Roughly 22% of Wave VI participants (i.e., Sample 2) answered the survey in-person; these participants also completed in-person assessments of cognitive, physical, and sensory functioning. The remaining 78% of Wave VI participants (i.e., Sample 1) answered the survey via the web.

Wave VI of Add Health also included a home exam for consenting survey participants. A total of 6,073 Wave VI participants completed the home exam. The home exam included anthropometric, cardiovascular, medications, and blood-based data collection.

More information on Wave VI design and data, as well as information on earlier waves of Add Health, can be found in the User Guides available on the Add Health website.

Additional Add Health Data

The Add Health Parent Study, often referred to as the Parent Study, is an ongoing project that builds upon the National Longitudinal Adolescent to Adult Health Study (Add Health). It collects information from the parents of Add Health participants, harmonizing health data across generations. This study aims to enhance the understanding of the role that families play through socioeconomic channels in the health and well-being of the parent generation and that of their offspring.

The Add Health Parent Study Phase 1 (Parents 2013-2018) gathered social, behavioral, and health survey data on a probability sample of the Add Health parents who were originally interviewed in 1995. Data for 2,013 Wave I parents, ranging in age from 50-80 years and representing 2,244 Add Health sample members, are available. Additionally, 988 current spouse/partner interviews are available.

This unique data set supports the analyses of inter-generational transmissions of (dis)advantage. Parents (2013-2018) data permits the examination of both short-term and long-term linkages and interactions between parents and their adult children.

Principal Investigators: Kathleen Mullan Harris, Ph.D., James E. Haar Distinguished Professor of Sociology at The University of North Carolina at Chapel Hill; Joseph Hotz, Ph.D., Arts and Sciences Professor of Economics at Duke University.

The Add Health Parent Study/Parents Phase 1 (2013-2018) data collection was funded by a grant from the National Institute on Aging (RO1AG042794) to Duke University, V. Joseph Hotz (PI) and the Carolina Population Center at the University of North Carolina at Chapel Hill, Kathleen Mullan Harris (PI).

Locating the Parents of Add Health R21AG042663 from NIA to Harris and Hotz.

Add Health Program Project P01HD31921; 1994-2021 to Harris from NICHD with cooperative funding from 23 other federal agencies and foundations. 

The newest phase of the Parent Study, Phase 2, will expand participation by increasing the sample of Non-Hispanic (NH) Black and Hispanic parents (and their current spouse/partners) represented in the Add Health Parent Study to result in the first nationally representative sample of adult children (ages 40-49), with longitudinal data from their parent generation (ages 58-90).

Phase 2’s data collection will include AD/ADRD assessments and DNA collection. For the first time ever, this will allow research on racial/ethnic disparities across two generations with social, behavioral, health, cognitive, and genomic data from both adult children and their parents. This one-of-a-kind dataset will support analyses of intergenerational transmissions of (dis)advantage, healthy aging, and cognition across a diverse array of communities within the US.

The Add Health Parent Study Phase 2 Principal Investigators: Dr. Kathleen Mullan Harris, Dr. V. Joseph Hotz, Dr. Krista M. Perreira, Dr. Naomi N. Duke, Duke University

The Add Health Parent Study Phase 2 (2023-2028) was funded by a grant from the National Institute on Aging (R01AG084071) to the Carolina Population Center at the University of North Carolina at Chapel Hill, Kathleen Mullan Harris (MPI) and Krista Perreira (MPI) and to Duke University, V. Joseph Hotz (MPI) and Naomi N. Duke (MPI).

SOGI-SES, or “Sexual Orientation/Gender Identity, Socioeconomic Status, and Health across the Life Course,” explores the relationship between sexual orientation/gender identity, socioeconomic status, and health. The SOGI-SES project collected, cleaned, disseminated and analyzed new data from a subset of the Add Health cohort comprised of sexual and gender minorities, broadly defined, and a comparison sample of cisgender heterosexuals. Data collection occurred in 2020 and 2021.

Principal Investigators: Carolyn T. Halpern at the University of North Carolina at Chapel Hill; Kerith J. Conron at the Williams Institute, UCLA.

Funding: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and the National Institute on Minority Health and Health Disparities under grants R01 HD087365 and R01 HD087365-03S1.

Visit the OMICS page for more information on the various Add Health OMICS studies.

Acknowledgement

The Add Health contract and data use agreement require that the following be included in each written report or other publication based on analysis of the Add Health data:

Data collection and dissemination for Wave VI of Add Health was funded by cooperative agreements U01 AG071448 (PI: Robert A. Hummer) and U01 AG071450 (MPIs: Robert A. Hummer and Allison E. Aiello) from the National Institute on Aging to the University of North Carolina at Chapel Hill, with cooperative funding from five other institutes and offices at the National Institutes of Health: the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute on Minority Health and Health Disparities, the National Institute on Drug Abuse, the Office of Disease Prevention, and the Office of Behavioral and Social Science Research. Waves I-V of Add Health were funded by grant P01 HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Add Health is currently directed by Robert A. Hummer at the University of North Carolina at Chapel Hill. Add Health was designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill.

Funders

Wave VI
National Institute of Aging (NIA)
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
National Institute of Drug Abuse (NIDA)
National Institute on Minority Health and Health Disparities (NIMHD)
Office of the Director, National Institutes of Health (OD/NIH)

Wave V
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
National Institute on Deafness and Other Communication Disorders (NIDCD)
National Institute on Drug Abuse (NIDA)
National Science Foundation (NSF)
Office of the Director, National Institutes of Health (OD/NIH)

Wave IV
Eunice Kennedy Shriver National Institute Of Child Health & Human Development (NICHD)
National Institute Of Nursing Research (NINR)
National Center On Minority Health And Health Disparities (NCMHD)
National Institute On Deafness And Other Communication Disorders (NIDCD)
National Institute On Alcohol Abuse And Alcoholism (NIAAA)
Office of the Director, National Institutes of Health (OD/NIH)
National Institute On Aging (NIA)
National Institute On Drug Abuse (NIDA)
National Cancer Institute (NCI)
National Institute of Allergy and Infectious Diseases (NIAID)
Office of Behavioral and Social Sciences Research, NIH (OBSSR)
Office of Research on Women’s Health, NIH (ORWH)
Office of the Assistant Secretary for Planning and Evaluation, DHHS (ASPE)
Office of Population Affairs, DHHS (OPA)
National Center for Injury Prevention and Control, Centers for Disease Control and
Prevention, DHHS (CDC)
Office of AIDS Research, NIH (OAR)
MacArthur Foundation

Add Health Co-funders 1994 to 2005
Eunice Kennedy Shriver National Institute Of Child Health & Human Development (NICHD)
National Institute On Drug Abuse (NIDA)
Office of the Director, National Institutes of Health (OD/NIH)
National Institute Of Nursing Research (NINR)
National Institute On Alcohol Abuse And Alcoholism (NIAAA)
National Institute On Deafness And Other Communication Disorders (NIDCD)
National Cancer Institute (NCI)
National Center for Health Statistics, Centers for Disease Control and Prevention, DHHS (NCHS)
National Institute of General Medical Sciences (NIGMS) National Institute of Mental Health (NIMH)
Office of Minority Health and Health Disparities, Centers for Disease Control and Prevention, DHHS (OMHHD)
Office of Minority Health, Office of Public Health and Science, DHHS (OMH)
National Institute of Allergy and Infectious Diseases (NIAID)
National Institute of Diabetes and Digestive and Kidney Disease (NIDDK)
Office of AIDS Research, NIH (OAR)
Office of Behavioral and Social Sciences Research, NIH (OBSSR)
Office of Research on Women’s Health, NIH (ORWH)
Office of Population Affairs, DHHS (OPA)
Office of the Assistant Secretary for Planning and Evaluation, DHHS (ASPE)
National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, DHHS (CDC)
National Science Foundation
Robert Wood Johnson Foundation