The effect of poverty on the relationship between household education levels and obesity in U.S. children and adolescents: an observational study

Abstract

Background: Although ample evidence has shown the link between childhood obesity and socioeconomic status including family income and household education levels, the mediating role of poverty in the association between household education levels and childhood obesity is unclear. This study aimed to quantify the extent to which family poverty levels contribute to the association between household education levels and obesity among US children and adolescents.

Methods: This cohort study used the nationally representative data of 21,754 US children and adolescents aged 6-17 years (National Health and Nutrition Examination Survey 1999-2018). We applied mediation analysis of the association between household education levels (less than high school, high school, and college or above) and obesity mediated through poverty (≤138% vs. >138% federal poverty level), adjusting for demographic characteristics of household head and their offspring. Obesity was defined as age- and sex-specific body mass index in the 95th percentile or greater using the 2000 Centers for Disease Control and Prevention growth charts.

Findings: Among 21,754 children and adolescents (weighted N = 43,544,684; mean age, 11.6 years; female, 49%), 9720 (weighted percentage, 33.0%) were classified as living in poverty and 4671 (weighted percentage, 19.1%) met the criteria for obesity. Low household education level (less than high school) showed increased risks of poverty (adjusted relative risk [95% CI], 5.82 [4.90-6.91]) and obesity (adjusted relative risk [95% CI], 1.94 [1.68-2.25]) compared to high household education level (college or above). We also quantified that poverty mediated 18.9% of the association between household education levels and obesity among children and adolescents. The mediation effect was consistently observed across age, gender, and race/ethnicity.

Interpretation: Poverty mediated the association between the low educational status of household heads and their offspring's obesity. Our findings highlight the importance of reducing obesity risk among the low-income population to minimize the burden of intergenerational health disparities due to socioeconomic status.

Funding: Japan Society for the Promotion of Sciences (22K17392).

Keywords: Childhood obesity; Intergenerational social disparity; Mediation analysis; Parental education; Poverty.

Fig. 1

An overview of the study. GED, general educational development; TE, total effect; IE, indirect effect. a) Using a nationally representative sample of US children and adolescents, causal mediation was applied to quantify the extent to which poverty mediates the relationship between household education levels and childhood obesity. b) Lower household education levels were associated with an increased risk of obesity compared to college or above household education (high school or GED, adjusted RR [95% CI] = 1.76 [1.55–1.99]; less than high school, adjusted RR [95% CI] = 1.94 [1.68–2.25]; p-value for trend <0.001). c) Poverty mediated 18.9% of the association between household education levels (less than high school vs. college or above) and obesity among children and adolescents. Although “total effect” and “indirect effect” are common terminologies in mediation analysis, our estimates based on observational study represent the association rather than the effect.