The neighborhood an adolescent lives in may influence his or her development of obesity, new study findings suggest. Specifically, investigators found that adolescents from close-knit neighborhoods were less likely to be obese.

Close-knit neighborhoods exhibited strong collective efficacy - neighbors get along and are willing to help each other, and many adults are role models for adolescents.

“There is an obesity epidemic in this country and treatment has focused on diet and exercise with relatively little success,” study author Dr. Deborah A. Cohen, a senior natural scientist at the Santa Monica, California-based RAND Corporation, said in a company statement.

The current findings imply that it may be necessary to “look at the neighborhood environment as potentially very important in controlling the obesity epidemic,” she told Reuters Health.

“The social environment that a child lives in is very strongly associated with how active they are, what they eat and how much they eat,” she said.

Previous studies show that a neighborhood’s level of collective efficacy is predictive of crime, premature death, death from cardiovascular disease and other health outcomes. In a survey of 684 households in 65 Los Angeles County neighborhoods, Cohen and her team investigated whether collective efficacy may also indirectly affect factors related to obesity. The study included 807 adolescences and 3000 adults.

Cohen’s group found that adolescents who lived in neighborhoods with high levels of collective efficacy were also less likely to be overweight or at risk for overweight and had a lower body mass index - a ratio of weight to height - than did their peers in other neighborhoods.

Adolescents in low-collective efficacy neighborhoods, on the other hand, were 64 percent more likely to be at-risk-for-overweight and 52 percent more likely to be overweight than those living in neighborhoods with an average level of collective efficacy, the researchers report in the journal Social Science & Medicine.

In fact, collective efficacy was more important in predicting obesity than the ethnic or racial make-up of the neighborhood, or the income of its residents, Cohen noted.

The reason for the association is unknown, but Cohen speculated that children in neighborhoods with high collective efficacy may be more likely to play outside rather than sit inside and watch television. Or, she said, “maybe (their) neighborhoods look different,” with more parks and fewer fast food restaurants.

Based on the findings, “we need to start looking at our environments,” she said, and ask: “Are there places for kids to play? Billboard advertisements for fast foods?”

Citing the potential for neighborhood groups to create a sports league or get a park for children to play in, she said, “together people can change their environment and make it healthy.”

SOURCE: Social Science & Medicine, January 2006.