(HealthDay News) – The prevalence of sufficient physical activity is increasing across counties in the United States, but has had little impact on obesity prevalence, according to a study published online July 10 in Population Health Metrics.

Laura Dwyer-Lindgren, MPH, from the University of Washington in Seattle, and colleagues used data from the Behavioral Risk Factor Surveillance System and the National Health and Nutrition Examination Survey to estimate obesity and physical activity annually from 2001–2011.

The researchers found that from 2001–2009 there was an increase in the prevalence of sufficient physical activity. Although levels were generally higher in men, greater increases were seen among women. The largest gains were reported by counties in Kentucky, Florida, Georgia, and California. In almost all counties, the increase in level of activity was matched by an increase in obesity during the same time period. In U.S. counties there was a low correlation between the level of physical activity and obesity. After controlling for changes in poverty, unemployment, number of doctors, percent rural, and baseline levels of obesity, the prevalence of obesity was 0.11% lower for every 1% increase in physical activity prevalence.

“Our study showed that increased physical activity alone has a small impact on obesity prevalence at the county level in the United States,” the authors write. “The rise in physical activity levels will have a positive independent impact on the health of Americans as it will reduce the burden of cardiovascular diseases and diabetes. Other changes such as reduction in caloric intake are likely needed to curb the obesity epidemic and its burden.”

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