CHAPEL HILL - Lack of access to school physical education programs and community recreation centers significantly decreases the chance that U.S. adolescents will be physically active, a major new University of North Carolina at Chapel Hill study shows.
Living in high-crime neighborhoods also cuts the likelihood of vigorous activity and boosts television and video watching and video- and computer-game playing, pastimes that contribute to obesity and eventual poor health, the study found. Adolescents whose families enjoy higher incomes and whose mothers are better educated tend to be more physically active than others are.
"When we started this research, we were looking at the critical problem of obesity facing our country," said Dr. Penny Gordon-Larsen, Dannon Institute postdoctoral fellow in interdisciplinary nutrition science at UNC-CH's Carolina Population Center. "Much of this obesity is due to overly sedentary lifestyles, which lead some teens to become couch potatoes. Our kids on the whole are very inactive and watch too much television, and inactive teens become inactive as adults."
Gordon-Larsen and colleagues conducted their study -- the most detailed of its kind and in some ways unique -- to discover what the United States could do as a society to begin to reduce obesity.
A report on their findings appears in the June issue of Pediatrics, a medical journal. Besides Gordon-Larsen, authors are Drs. Barry M. Popkin, professor of nutrition and project principal investigator at the UNC-CH schools of public health and medicine, and Robert G. McMurray, professor of exercise and sport science.
Researchers analyzed information from the National Longitudinal Study of Adolescent Health (Add Health) on 17,666 teen-agers enrolled in the seventh to 12th-grades across the nation in 1996. Data came from detailed, confidential surveys of teens about their experiences, practices and attitudes and included 3,933 non-Hispanic blacks, 3,148 Hispanics and 1,337 Asians.
The team looked chiefly at patterns of both physical activity and behaviors such as watching television and videos and electronic game playing that were combined into what they termed "inactivity," Gordon-Larsen said. The two categories often are related but are not necessarily opposites.
Other findings were that:
- only 21.3 percent of adolescents studied participated in one or more days of physical education in school per week.
- physical activity levels were chiefly affected by environmental factors such as neighborhood crime, school physical education, and recreation center use, while inactivity levels were most closely associated with social factors such as family income and mothers' education.
- on the whole, U.S. adolescents get little vigorous exercise and spend much time in TV and video viewing and computer/video games. Being female and Hispanic or black meant even less vigorous exercise.
- the percentage of adolescents who fell into the highest activity category increased from 30 percent among those reporting no school physical education to almost 50 percent among those having PE five times a week.
"There has been extensive discussion of the need to increase physical activity, and PE classes in school have been a major target," Popkin said. "This is the first major national study of the importance of PE. Moreover, it shows that few adolescents participate now in PE."
The project also provides the first evidence that community recreation facilities are important for adolescent activity -- a very important factor considering the dearth of safe and quality recreation facilities in many poor communities, he said. Coupled with record levels of obesity and huge amounts of TV viewing among teens, the results show how important community resources such as PE and recreation centers are in raising activity levels.
"Adolescents from poor families fared even worse, since high crime rates, low income and less education among mothers reduced vigorous physical activity and increased TV, video and computer/video game use," Popkin said. "However, we must remember that teen obesity is not just a problem among poor people or minorities. It is a huge problem for all Americans."
Gordon-Larsen and her colleagues believe that introducing healthy activity habits during childhood and adolescence will lead to more active adults who lead longer, healthier lives. "School is really the perfect place to start," she said. "If we can get schools to provide safe and accessible places for kids to be active, then there's a huge potential to reach a great number of kids. If the schools can't or won't do that, then community recreation centers can make a big difference also."
The National Institute of Child Health and Human Development and the Dannon Institute sponsored the research.
Note: Gordon-Larsen and Popkin can be reached at (919) 843-9966 and 966-1732, respectively.
School of Public Health Contact: Lisa Katz, (919) 966-7467.
Contact: David Williamson, (919) 962-8596.
Journal
PEDIATRICS