"This research highlights the critical nature of the adolescent and young adult period for developing and continuing obesity," said Dr. Penny Gordon-Larsen, assistant professor of nutrition at the UNC schools of public health and medicine and a fellow at the Carolina Population Center. "During that transitional period, the proportion of adolescents becoming and remaining obese is particularly high. Preventive and treatment efforts are critically needed."
Using National Longitudinal Study of Adolescent Health data, Gordon-Larsen conducted the research with Drs. Linda S. Adair and Barry Popkin, both professors of nutrition at UNC, and graduate student Melissa C. Nelson. She presented their results in Ft. Lauderdale, Fla., Monday (Oct. 13) at a meeting of the North American Association for the Study of Obesity.
The researchers set out to investigate population-wide trends in obesity between teen-age and adult years in the United States because those rates are little known, and obesity is a serious and growing public health problem, Gordon-Larsen said. They analyzed nationally representative data collected from thousands of U.S. adolescents enrolled in the UNC-based adolescent study, also known as the Add Health project.
Specifically, they analyzed information gathered in 1996 from a sample of 9,561 teens from across the nation during the second data collection wave of the study and then again measured the heights and weights of those same teens five years later when they were ages 18 to 26 during the project's third wave. The team determined obesity among the subjects using age and sex-specific criteria from the 2000 Centers for Disease Control growth charts and International Obesity Task Force reference data.
"Our key findings included the large incidence of obesity, particularly among black and Hispanic females," Gordon-Larsen said. "Over the five-year exam period, 18 percent and 15 percent of them respectively, became obese.
"At the beginning, 11 percent of teens studied were obese, and as they aged and became young adults, 22 percent were obese," the scientist said.
Older adolescents had a higher rate of obesity and were more likely to remain obese than their younger counterparts, she said. The population shift in body mass was evident in the higher body mass index range. The Add Health analysis sample represents about 16.6 million school-aged youth.
"As most people know by now, obesity is a huge problem for all groups of adolescents, but it's particularly a problem among minority populations," she said. "Among the health problems it creates or makes worse are diabetes, cardiovascular disease and high blood pressure."
Changing the U.S. culture and environment to make diets healthier, increase exercise and improve lifestyle choices for Americans of all ages, but particularly those at highest risk -- minority populations that are under-served in health care -- should become a national priority, Gordon-Larsen said.
The new analysis was supported in part by grants from the National Institute of Child Health and Human Development, which has been the major long-term supporter of the Add Health study. The larger, continuing study has involved collecting and analyzing responses from tens of thousands of U.S. adolescents surveyed about their lives, health and habits.
Note: Gordon-Larsen can be reached at 919-843-9966 Friday or at pglarsen@email.unc.edu during the meeting.
School of Public Health Contact: Lisa Katz, 966-7467
News Services Contact: David Williamson, 962-8596