Prevalence and Trends in Obesoty Among US Adults, 1999-2008

Context The prevalence of obesity increased in the United States between 1976-1980 and 1988-1994 and again between 1988-1994 and 1999-2000. Objective To examine trends in obesity from 1999 through 2008 and the current prevalence of obesity and overweight for 2007-2008. Design, Setting, and Participants Analysis of height and weight measurements from 5555 adult men and women aged 20 years or older obtained in 2007-2008 as part of the National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the US population. Data from the NHANES obtained in 2007-2008 were compared with results obtained from 1999 through 2006. Main Outcome Measure Estimates of the prevalence of overweight and obesity in adults. Overweight was defined as a body mass index (BMI) of 25.0 to 29.9. Obesity was defined as a BMI of 30.0 or higher. Results In 2007-2008, the age-adjusted prevalence of obesity was 33.8% (95% confidence interval [CI], 31.6%-36.0%) overall, 32.2% (95% CI, 29.5%-35.0%) among men, and 35.5% (95% CI, 33.2%-37.7%) among women. The corresponding prevalence estimates for overweight and obesity combined (BMI ≥25) were 68.0% (95% CI, 66.3%-69.8%), 72.3% (95% CI, 70.4%-74.1%), and 64.1% (95% CI, 61.3%-66.9%). Obesity prevalence varied by age group and by racial and ethnic group for both men and women. Over the 10-year period, obesity showed no significant trend among women (adjusted odds ratio [AOR] for 2007-2008 vs 1999-2000, 1.12 [95% CI, 0.89-1.32]). For men, there was a significant linear trend (AOR for 2007-2008 vs 1999-2000, 1.32 [95% CI, 1.12-1.58]); however, the 3 most recent data points did not differ significantly from each other. Conclusions In 2007-2008, the prevalence of obesity was 32.2% among adult men and 35.5% among adult women. The increases in the prevalence of obesity previously observed do not appear to be continuing at the same rate over the past 10 years, particularly for women and possibly for men. Conclusions Published online January 13, 2010 (doi:10.1001/jama.2009.2014). The National Health and Nutrition Examination Survey (NHANES) provides the opportunity to track trends in the prevalence of obesity in the United States by collecting data on height and weight measurements. Data from 1988-1994 showed that the prevalence of obesity in adults had increased by approximately 8 percentage points in the United States since 1976-1980, after being relatively stable over the period 1960-1980.1,2 Analyses of data from 1999-2000 showed further increases in obesity for both men and women and in all age groups.3 The increases in obesity from 1976-1980 to 1988-1994 were statistically significant in all sex and age groups. The increases in obesity from 1988-1994 to 1999-2000 were statistically significant in all sex and age groups except men aged 40 to 59 years. Analyses of data from 2001-2002 and 2003-2004 suggested increasing trends since 1999-2000 among men but not among women.4,5 Comparisons between 2003-2004 and 2005-2006 showed no significant changes but had limited statistical power.6 Herein we report the results from the latest NHANES data from 2007-2008 regarding population trends in obesity and compare the results over the 10-year period from 1999 through 2008.