Meanwhile, two other studies examined life expectancy and physical activity on a county-by-county basis in America. Both were conducted by researchers at the Institute for Health Metrics and Evaluation, and both were published online in the open-access, peer-reviewed journal Population Health Metrics, which is edited by Dr. Murray.
In the first study, "Prevalence of Physical Activity and Obesity in US Counties, 2001-2011: A Road Map for Action," physical activity did not increase overall in the United States during the study period (2001-2009), but the percentage of the population considered obese did. The authors found that just because an area had higher physical activity levels did not mean that there would be a corresponding drop in obesity. They wrote that from 2001 to 2009, "for every 1 percentage point increase in physical activity, obesity prevalence was 0.11 percentage points lower" (Popul. Health Metr. 2013;11:7 [doi: 10.1186/1478-7954-11-7]).
Some counties – in Florida, Georgia, and Kentucky – saw large gains in physical activity. Among women, for instance, the largest increase in sufficient physical activity (defined as 150 minutes of moderate activity or 75 minutes of vigorous activity weekly) was seen in Morgan County, Ky., where the rate rose from 26% to 44% during 2001-2009.
Generally, physical activity was worse for men and women who lived along the Texas-Mexico border, the Mississippi Valley, parts of the Deep South, and West Virginia, according to the study.
Douglas County, Colo., had the highest rate of activity in the United States (90%) for men in 2011, while Marin County, Calif., had highest rate for women (90%). Wolfe County, Ky., had the lowest rate for men (55%), and McDowell County, W.Va., had the lowest rate for women (51%).
Obesity rates tended to track with activity rates, with higher rates in the South and lower rates in urban areas like San Francisco, New York, and Washington, D.C.
The authors also published a county-by-county analysis of life expectancy, "Left Behind: Widening Disparities for Males and Females in US County Life Expectancy, 1985-2010." They reported that among the top-achieving counties, female life expectancy in 2010 was 85 years (or about 5 years more than the national average) and male life expectancy was 81.7 years (also about 5 years greater than the national average). But, they said, in many counties there has been no increase, or in some cases, declines in life expectancy, especially for women. There was a dramatic increase in inequality in life expectancy at birth among U.S. counties between 1985 and 2010, they concluded (Popul. Health Metr. 2013;11:8 [doi: 10.1186/1478-7954-11-8]).
Dr. Murray’s work is supported in part by the National Institutes of Health and in part by the Bill and Melinda Gates Foundation.
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