Educational disparity in obesity among U.S. adults, 1984-2013

Purpose: Examine the annual trends in educational disparity in obesity among U.S. adults aged 18years and more from 1984 to2013. Methods: Secondary data analysis of 6,147,379 participants in a repeated cross-sectional nationally representative health survey of U.S. adults. Results: The obesity prevalence among people with primary school or lower education increased from 17.46% or 3.41 times the prevalence among college graduates (5.12%) in 1984 to 36.16% or 1.73 times the prevalence among college graduates (20.94%) in 2013. In any given year, the obesity prevalence increased monotonically with lower education level. The obesity prevalence across education subgroups without a college degree gradually converged since early 2000s, whereas that between those subgroups and college graduates diverged since late 1980s. Absolute educational disparity in obesity widened by 60.84% to 61.14% during 1984-2013 based on the absolute concentration index and the slope index of inequality, respectively; meanwhile, relative educational disparity narrowed by 52.06% to 52.15% based on the relative index of inequality and the relative concentration index, respectively. The trends in educational disparity in obesity differed substantially by gender, race/ethnicity, age group, and obesity severity. Conclusions: There was substantial educational disparity in obesity among U.S. adults and the trend differed across population subgroups.