From Adolescence to Midlife: How Add Health Became a National Research Resource at UNC-Chapel Hill

By Grayson Mendenhall
gkm4unc@email.unc.edu

For more than three decades, a groundbreaking research study born at the University of North Carolina at Chapel Hill has followed the lives of thousands of Americans, creating one of the world’s richest sources of information on health and human development.

The National Longitudinal Study of Adolescent to Adult Health, better known as Add Health, began in the mid-1990s with an ambitious idea: follow a nationally representative group of young people over time to better understand how the experiences, relationships, environments, and opportunities of adolescence shape health and well-being across the life course. Today, that vision continues through multiple waves of data collection and a growing focus on aging, positioning UNC’s Carolina Population Center (CPC) as the home of one of the nation’s most influential longitudinal studies.

Add Health’s scope was extraordinary from the start. The study launched with more than 20,000 adolescents in grades 7-12 during the 1994-95 school year and has since followed those participants through six waves of data collection, most recently between 2022 and 2025. In 2026, the study began a new phase, Wave VII, extending research into the participants’ middle-age years. Now primarily funded by the National Institute on Aging, but with co-funding support from six additional National Institutes of Health entitles, Wave VII of Add Health will be providing nationally representative data on the health and aging of this large cohort of individuals as they move in their 50s and beyond.

Support from CPC made the project possible

The study’s longevity reflects not only scientific foresight on the part of the study’s principal investigators, but also the institutional capacity that made such an undertaking possible.

At UNC, the Carolina Population Center has provided the infrastructure, technical expertise, and long-term stewardship required to host a project of national scale. From grant submission to budgeting to data management, dissemination, and security, CPC has provided the foundation that allowed researchers to pursue questions few institutions could tackle alone. At the same time, the Center brought together scholars from sociology, demography, epidemiology, public health, medicine, statistics, and other disciplines who shared a willingness to ask big questions about health and human development and to work together to answer them.

That interdisciplinary approach remains one of Add Health’s defining strengths.

Unlike studies built primarily from administrative records, repurposed datasets, or computer-generated simulations, Add Health is rooted in information provided directly by participants themselves. Over more than three decades thus far, more than 20,000 individuals have repeatedly shared details about their lives, families, communities, experiences, and health. Researchers have combined that individual–level survey data with biological, environmental, and contextual information to create an exceptionally detailed picture of how health unfolds over time as people age.

The result is a dataset unlike any other

Add Health combines social, behavioral, environmental, and biological information collected from the same individuals across decades. This exceptionally rich data provides the information necessary for researchers to examine how early-life experiences are connected to later outcomes, providing insights that are difficult or impossible to obtain from shorter-term studies. As the original participants move into midlife and beyond, the study is increasingly helping scientists understand aging, chronic disease, resilience, and the factors that contribute to healthy lives over the long term.

The Impact of Add Health extends far beyond UNC.

Add Health investigators at UNC regularly use Add Health data in their research. Their findings have been published in many scientific journals and have been used in the undergraduate and graduate courses they teach in their home departments at UNC. But even more impressive, data from Add Health have become a global resource used by more than 50,000 researchers to date. More than 5,000 peer-reviewed publications have relied on data from Add Health to date, and its data have supported more than 1,200 MA theses and doctoral dissertations while generating additional grant-funded research projects across a wide range of disciplines and among scholars outside of the core study team. The study’s influence on scientific training has been equally significant, giving generations of students and early-career scholars access to data capable of addressing complex questions and launching new lines of inquiry.

Accessibility has led to broad impact

UNC and CPC have long treated Add Health as a resource for the academic community. Public-use data are available at no charge, allowing students and scholars at academic institutions, regardless of size or resources, to utilize the rich data in their own research projects. At the same time, CPC maintains rigorous protections to safeguard participant confidentiality and data security, ensuring that respondents’ trust remains central to the project’s mission.

The study’s public-use data have become one of the most widely used resources available through the Inter-university Consortium for Political and Social Research (ICPSR), helping democratize access to high-quality longitudinal data and ensuring that important scientific questions can be pursued by researchers across the academic spectrum.

For UNC-Chapel Hill, Add Health represents more than a successful research project. It is a demonstration of what university-based research centers can achieve when they combine scientific ambition with sustained institutional support. What began as a bold effort to understand adolescent health has evolved into a national scientific gem, one that continues to generate discoveries, train early career researchers, and deepen understanding of the factors that shape health across the lifespan in the United States.

More than 30 years after its launch, Add Health stands as a testament to the vision of the researchers who conceived it and have enhanced it, the thousands of participants who continue to contribute their experiences, and the Carolina Population Center’s enduring commitment to building research resources that serve the broader scientific community.