CHAPEL HILL  - The University of North Carolina at Chapel Hill's Carolina Population Center has received a five-year, $28 million grant for the National Longitudinal Study of Adolescent to Adult Health. Now entering its 20th year of National Institutes of Health funding, Add Health is the largest, most comprehensive longitudinal study of the health of adolescents ever undertaken in the United States.

Since 1994 when researchers first conducted extensive interviews with a nationally representative sample of 20,000 students in grades 7-12, Add Health has provided the data for more than 2,000 scientific papers by more than 10,000 researchers around the world. The foundational studies have mapped the obesity epidemic, brought the silent epidemic of largely undetected high blood pressure in young adults into public awareness and pioneered work on how their social and behavioral lives interact with genetic makeup.

The new funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), which deemed the study "a national treasure" for the scientific community, will allow researchers worldwide to better understand how teens' health, social experience, genetic profile and living environments might influence their health and behavior later in adulthood.

"At a time when health care costs are skyrocketing, this knowledge could potentially affect the ability of healthcare providers and policy makers to create a pathway to better health for the next generation," said Kathleen Mullan Harris, James E. Haar Distinguished Professor of Sociology at UNC-Chapel Hill, who leads the project in a press release from the school. "The NIH has made a major investment to understand how social, behavioral, and biological linkages in early life shape the behavior and health of adolescents as they age into adulthood - and now we're starting to see the payoff for this investment."

Starting in 2015, the five-year project will collect a new round of social and biological data from the original respondents when they are in their thirties and for the first time will capture information on respondents' birth and early childhood experiences. Together with existing Add Health data collected over the past 20 years, the scientific community will be able to investigate an invaluable 40-year longitudinal record of the Add Health cohort from birth through the fourth decade of life.

Harris, who was recently elected to the National Academy of Sciences, has put together a team of sociologists, psychologists, epidemiologists, nutritionists, cardiologists, geneticists, economists and research methodologists to test hypotheses about the causes of chronic disease and to inform public health policies for reducing chronic disease prevalence, disparities and costs in America.

"These are young adults, so you think they should be healthy, but in the last interview wave we found 25 percent have hypertension and six percent have diabetes," she said. "That's a very high percentage among 24- to 32-year-olds. As they age, we're expecting to see an explosion of chronic illness earlier than would be normally expected in their life course. That's something we should pay attention to."