Income Gradient in Children’s Physical Activity: Diminished Returns in Black Families

Background: While socioeconomic status (SES) indicators, such as family income, are among the primary drivers of individual health behaviors, the effects of these indicators on health behaviors may be weaker for racial/ethnic minorities, as described by the Marginalization related Diminished Returns (MDRs) phenomenon. Objectives: Built on the MDRs framework, this study used a national sample of 9 and 10 year old children with the following two aims: First, to test the association between household income and physical activity, and second, to test racial/ethnic variation in these associations. Methods: This cross-sectional study used the Adolescent Brain Cognitive Development (ABCD) baseline data. Participants included 9358 individuals who were either Black or White. Age, sex, racial/ethnicity, family structure (parental marital status), and frequency of physical activity were measured. Linear regression was used for data analysis. Results: Overall, high family income showed a positive association with physical activity in the overall population. We documented a statistically significant interaction between race/ethnicity and household income on frequency of physical activity, showing weaker effects of family income on children’s physical activity in Black than White families. Conclusion: We observed that household SES indicators, such as family income, have a larger effect on increasing children’s physical activity in White than Black families. Due to the existing MDRs, defined as weaker effects of family SES for racial/ethnic minority than White families, Black children from high SES families engage in less healthy behaviors than their White counterparts. MDRs sustain racial/ethnic disparities across class and SES lines.