That's not the only reason that people with less money in this country often are less active and too heavy, but it appears to be a key factor, the researchers said. The long-term consequences are poorer health and shorter lives.
In their study of some 20,000 U.S. teens, the researchers explored whether resources available for physical activity were distributed relatively equally across all segments of the population, said Dr. Penny Gordon-Larsen, assistant professor of nutrition, a department jointly housed within UNC's schools of public health and medicine. They especially wanted to learn whether minority and low-income groups – in which obesity levels are high and exercise levels low – had access to such resources to about the same degree as people in richer communities.
"We expected to find that private, fee facilities would be more common in more affluent areas, but the extent and magnitude of the lack of access in poorer communities was very surprising," Gordon-Larsen said. "Even the types of facilities we think of as most equitably allocated, like YMCAs, public parks and youth organizations, were significantly less common in poorer areas."
A report on the findings will appear in the February issue of the journal Pediatrics. Besides Gordon-Larsen, authors are Dr. Barry Popkin, professor of nutrition; recent UNC doctorate recipient Dr. Melissa C. Nelson; and Phil Page, director of the Spatial Analysis Unit of UNC's Carolina Population Center.
The team extended its research to examine the impact of facilities on behavior.
"We found that each facility in the adolescents' communities increased the likelihood that they would meet physical activity recommendations and reduced their likelihood of being overweight," Gordon-Larsen said. "Larger numbers of facilities had a greater impact on increasing exercise and reducing overweight."
Information for the investigation came from Add Health, a continuing UNC-based major national study of U.S. teens' healthy and unhealthy behaviors and attitudes. The National Institute of Child Health and Human Development and 17 other agencies underwrite Add Health.
Investigators extracted data about the adolescents' weight and activity patterns gathered during detailed interviews in 1994 and 1995 and linked that information to further detailed information about the communities in which adolescents lived. The investigators used national databases and satellite-derived images of areas where subjects lived, along with socio-economic data from almost a fifth of all U.S. census block groups.
Factored into the analysis were the numbers of public and private exercise facilities, schools, universities, public beaches, pools, tennis courts, youth centers, parks, camps and athletic clubs within communities.
"This issue, termed health disparities between different race, ethnic and income groups in the United States, represents one of the major health dilemmas facing the nation," said Popkin, who also directs UNC's Interdisciplinary Obesity Center. "This is the first study to empirically show a major systematic factor in our environment – namely a lack of recreation resources – explains an important component of this difference in health."
The findings underscore the major need for investment in physical activity facilities and resources, particularly in less advantaged and minority communities, Gordon-Larsen said. "When we look at obesity trends, particularly in children, adolescents and minority groups who are disproportionately affected, it is absolutely clear that population-level efforts to curb these trends are needed."
The National Institute of Child Health and Human Development, the National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of Environmental Health Sciences, all components of the National Institutes of Health, supported the new research. Support also came from the U.S. Centers for Disease Control and Prevention.
Gordon-Larsen and Popkin are Carolina Population Center members.
Note: Gordon-Larsen can be reached at (919) 843-9966 or pglarsen@unc.edu.
UNC School of Public Health contact: Ramona DuBose, 966-7467 or ramona_dubose@unc.edu
UNC News Services contact: Deb Saine, (919) 962-8415 or deborah_saine@unc.edu