Obesity prevalence varies by income and education level, although patterns might differ among adults and youths ( 1 – 3 ). Previous analyses of national data showed that the prevalence of childhood obesity by income and education of household head varied across race/Hispanic origin groups ( 4 ). CDC analyzed 2011–2014 data from the National Health and Nutrition Examination Survey (NHANES) to obtain estimates of childhood obesity prevalence by household income (≤130%, >130% to ≤350%, and >350% of the federal poverty level [FPL]) and head of household education level (high school graduate or less, some college, and college graduate). During 2011–2014 the prevalence of obesity among U.S. youths (persons aged 2–19 years) was 17.0%, and was lower in the highest income group (10.9%) than in the other groups (19.9% and 18.9%) and also lower in the highest education group (9.6%) than in the other groups (18.3% and 21.6%). Continued progress is needed to reduce disparities, a goal of Healthy People 2020. The overall Healthy People 2020 target for childhood obesity prevalence is 130% to ≤350%, and >350% of FPL. The cut-off point for participation in the Supplemental Nutrition Assistance Program is 130% of FPL, and 350% provides relatively equal sample sizes for each income group. Education was defined using education level of head of household and was categorized as a high school graduate or less, some college, and college graduate. All estimates accounted for the complex survey design including examination sample weights. Confidence intervals for estimates were constructed using the Korn and Graubard method ( 7 ). Differences between groups were tested using a 2-sided univariate t statistic (p 130% to ≤350% 1,974 19.9 (16.8–23.3) 18.0 (12.6–24.6) 19.9 (15.5–25.0) 8.9 (4.9–14.6) 23.7 (19.4–28.5) >350% 1,256 10.9 (8.0–14.4)*,† 11.0 (7.3–15.7) 19.8 (12.2–29.4) 4.4 (1.9–8.4)*,§ 11.8 (7.5–17.4)*,† Females ≤130% 1,539 19.7 (17.4–22.1) 17.8 (13.3–23.1) 19.9 (15.7–24.6) 8.4 (2.6–19.1)¶ 22.5 (18.9–26.3) >130% to ≤350% 969 21.5 (16.9–26.8) 21.2 (13.0–31.6) 21.6 (16.3–27.6) 8.2 (2.4–19.0)¶ 22.7 (17.0–29.2) >350% 613 8.0 (5.0–12.0)*,† 7.2 (3.5–12.8)*,† 21.1 (9.6–37.2) 1.3 (0.1–4.8)¶ 13.8 (6.3–25.2) Males ≤130% 1,592 18.1 (15.5–21.0) 13.5 (9.2–18.7) 19.0 (15.7–22.6) 18.0 (10.1–28.6) 23.1 (18.0–28.9) >130% to ≤350% 1,005 18.4 (15.6–21.4) 15.0 (10.0–21.2) 18.1 (12.1–25.5) 9.5 (3.9–18.7)§ 24.6 (20.0–29.7) >350% 643 13.7 (9.5–18.8) 14.7 (9.2–21.9) 18.7 (12.1–26.9) 7.6 (2.8–16.0)*,§ 10.0 (4.8–17.9)*,† Education level of head of household Total High school graduate or less 3,254 21.6 (20.0–23.3) 19.6 (16.2–23.3) 21.1 (17.5–25.0) 13.2 (8.5–19.3) 24.2 (20.9–27.7) Some college 1,936 18.3 (15.4–21.5)** 17.6 (12.4–23.9) 19.7 (16.3–23.4) 12.0 (6.0–20.7) 19.9 (16.2–23.9) College graduate 1,464 9.6 (7.3–12.5)**,†† 8.5 (5.8–12.1)**,†† 15.4 (9.8–22.5) 5.5 (3.1–8.9)** 13.5 (6.9–22.8)** Females High school graduate or less 1,583 22.7 (20.7–24.9) 22.5 (17.5–28.1) 21.0 (16.0–26.7) 9.2 (4.4–16.5) 23.9 (20.1–28.0) Some college 938 18.3 (14.6–22.6)** 18.0 (11.8–25.7) 22.1 (17.4–27.4) 8.0 (1.3–23.7)¶ 17.3 (12.5–23.0)** College graduate 739 8.5 (5.5–12.4)**,†† 7.5 (3.9–12.8)**,†† 16.3 (10.2–24.1) 3.3 (0.7–9.2)¶ 14.0 (6.8–24.3)** Males High school graduate or less 1,671 20.6 (18.1–23.2) 16.9 (11.6–23.3) 21.1 (17.5–25.1) 16.9 (9.0–27.7) 24.4 (20.5–28.7) Some college 998 18.3 (14.7–22.4) 17.3 (11.0–25.3) 17.2 (13.4–21.6) 14.6 (6.7–26.4) 22.3 (15.9–29.8) College graduate 725 10.7 (7.6–14.7)**,†† 9.6 (5.5–15.2)** 14.5 (6.9–25.4) 7.9 (3.8–14.0) 12.9 (5.8–23.9) §,** Abbreviation: CI = confidence interval. * Significantly different from ≤130% of FPL, p 130% to ≤350% of FPL, p 40%. ** Significantly different from high school graduate or less, p 130% to ≤350% of FPL. † Quadratic trend (p<0.05) for males ≤130% of FPL. The figure above is a line graph showing trends in obesity prevalence among youths (persons aged 2–19 years), by household income, in the United States, from 1999–2002 through 2011–2014. Obesity prevalence among youths increased from 1999–2002 to 2011–2014 among females and males in households headed by persons with the least education (high school graduate or less) and among females in households headed by persons with some college education. There were no other significant trends. In addition, the difference in childhood obesity prevalence between the lowest and highest head of household education groups increased over time for females but not for males (Figure 2). FIGURE 2 Trends* in prevalence of obesity among youths (persons aged 2–19 years), by education level of head of household — National Health and Nutrition Examination Survey, United States, 1999–2002 through 2011–2014 * Linear trend (p<0.05) for females, high school graduate or less and some college, and males, high school graduate or less. The figure above is a line graph showing trends in prevalence of obesity among youths (persons aged 2–19 years), by education level of head of household, in the United States, from 1999–2002 through 2011–2014. Discussion During 2011–2014, the relationships between childhood obesity and income and childhood obesity and education of household head were complex, differing depending upon the subgroup of the population. The prevalence of obesity among youths living in households headed by college graduates was lower than that among those living in households headed by less educated persons for each race-Hispanic origin group. The same was not true for those living in the highest income group. Moreover, differences by income and education of household head are widening among females. Similar to results based on data from 2005 to 2008 ( 4 ), during 2011–2014 childhood obesity prevalence was lower among youths living in households in the highest income group. However, this was not the pattern seen in all subgroups. For example, obesity prevalence was lower in the highest income group compared with the other groups among non-Hispanic white females, but not among non-Hispanic black females, non-Hispanic white males, or non-Hispanic black males. Obesity prevalence decreased as head of household education increased in all subgroups examined. The prevalence of obesity was consistently lowest among children in households headed by college graduates, which differed from the pattern seen by income level. This difference in the relationship between obesity and income versus education has been observed in at least one other study ( 8 ). In addition, some relationships changed since 2005–2008. For example, there was a significant decreasing trend in obesity prevalence by income among non-Hispanic white males during 2005–2008 ( 4 ) but there were no differences during 2011–2014. This report also presents differences in childhood obesity prevalence by income and education among non-Hispanic Asian youths in the United States. It has been suggested that the cut-off point that typically defines obesity might underestimate associated health risks among Asian persons ( 9 ). The findings in this report are subject to at least one limitation. The sample size was small among some subgroups, such as non-Hispanic Asian females living in households with income above 350% of the FPL, where the prevalence of obesity is very low (1.3%) and the sample size is small (138). Additional years of data might provide more information about obesity prevalence by income, especially among non-Hispanic Asian youths. Trends in childhood obesity prevalence by income and education level of head of household indicate that disparities have existed at least since NHANES III, 1988–1994 ( 10 ). These differences have widened since 1999–2002 among females but not among males, where differences in obesity prevalence by income and education of the head of household have remained relatively constant from 1999–2002 to 2011–2014. These findings demonstrate that lower levels of income are not universally associated with childhood obesity. The association is complex and differs by sex, race, and Hispanic origin, and possibly over time. Differences by education are more consistent across subgroups than differences by income. More progress is needed to reduce disparities in childhood obesity prevalence, an important Healthy People 2020 objective. Summary What is already known about this topic? Studies have suggested that childhood obesity prevalence varies by income and education, although patterns might differ between adults and youths. What is added by this report? Analysis of data from the 2011–2014 National Health and Nutrition Examination Survey (NHANES) demonstrates that childhood obesity prevalence patterns among persons aged 2–19 years by household income are less consistent by race and Hispanic origin than are the patterns by level of education attained by the head of household. Moreover, the differences in childhood obesity prevalence by income and education of household head are widening among females while differences among males have remained relatively constant over time. What are the implications for public health practice? NHANES will continue to be an important source of data for monitoring disparities in childhood obesity. These data will help track the Healthy People 2020 objective of reducing disparities and might inform obesity prevention programs at the federal, state, and local levels.
