Four Decades of Obesity Trends among Non-Hispanic Whites and Blacks in the United States: Analyzing the Influences of Educational Inequalities in Obesity and Population Improvements in Education

Both obesity (body mass index ≥ 30) and educational attainment have increased dramatically in the United States since the 1970s. This study analyzed the influences of educational inequalities in obesity and population improvements in education on national obesity trends between 1970 and 2010. For non-Hispanic white and black males and females aged 25–74 years, educational differences in the probability of being obese were estimated from the 1971–2012 National Health and Nutrition Examination Surveys, and population distributions of age and educational groups, from the 1970 Census and 2010 American Community Survey. In the total population, obesity increased from 15.7% to 38.8%, and there were increases in the greater obese probabilities of non-college graduates relative to four-year college graduates. The increase in obesity would have been lower by 10% (2.2 percentage points) if educational inequalities in obesity had stayed at their 1970 values and lower by one third (7.9 points) if obesity inequalities had been eliminated. Obesity inequalities were larger for females than males and for whites than blacks, and obesity did not differ by education among black males. As a result, the impact of obesity inequalities on the obesity trend was largest among white females (a 47% reduction in the obesity increase if obesity inequalities had been eliminated), and virtually zero among black males. On the other hand, without educational improvements, the obesity increase would have been 9% more in the total population, 23% more among white females and not different in the other three subpopulations. Results indicate that obesity inequalities made sizable contributions to the obesity trends, and the obesity reductions associated with educational improvements were more limited.

自20世纪70年代以来，美国的肥胖症（身体质量指数≥30）患病率与国民受教育程度均出现了显著攀升。本研究针对1970年至2010年的全国肥胖流行趋势，分析了肥胖相关教育不平等以及国民教育水平提升对该趋势的影响。针对25至74岁的非西班牙裔白人与黑人男性、女性群体，研究团队通过1971-2012年全国健康与营养检查调查（National Health and Nutrition Examination Surveys）估算了不同教育水平群体间的肥胖患病概率差异，并借助1970年美国人口普查与2010年美国社区调查（American Community Survey）获取了年龄与教育群体的人口分布数据。整体人群中，肥胖患病率从15.7%升至38.8%，且未持有大学文凭群体相较于四年制大学毕业生的肥胖患病概率均有所升高。若肥胖相关的教育不平等维持在1970年的水平，整体人群的肥胖患病率增幅将降低10%（2.2个百分点）；若完全消除肥胖相关的教育不平等，患病率增幅将降低三分之一（7.9个百分点）。肥胖相关教育不平等程度在女性群体中高于男性，在白人群体中高于黑人群体，且黑人男性的肥胖患病率并未呈现显著的教育差异。因此，肥胖相关教育不平等对肥胖流行趋势的影响在白人女性群体中最为显著——若消除该不平等，白人女性的肥胖患病率增幅将减少47%，而在黑人男性群体中几乎无影响。另一方面，若未发生国民教育水平的提升，整体人群的肥胖患病率增幅将高出9%，白人女性群体的增幅将高出23%，其余三个亚人群的增幅则无明显差异。研究结果表明，肥胖相关教育不平等对肥胖流行趋势做出了可观的贡献，而国民教育水平提升所带来的肥胖患病率降低效果则相对有限。