Body mass index trajectories from adolescence to midlife: differential effects of parental and respondent education by race/ethnicity and gender.

OBJECTIVES: Race/ethnicity and education are among the strongest social determinants of body mass index (BMI) throughout the life course, yet we know relatively little about how these social factors both independently and interactively contribute to the rate at which BMI changes from adolescence to midlife. The purpose of this study is to (1) examine variation in trajectories of BMI from adolescence to midlife by mothers' and respondents' education and (2) determine if the effects of mothers' and respondents' education on BMI trajectories differ by race/ethnicity and gender.
DESIGN: We used nationally representative data from the National Longitudinal Survey of Youth. Our sample included white (n=4433), black (n=2420), and Hispanic (n=1501) respondents. Self-reported height and weight were collected on 16 occasions from 1981 to 2008. We employed two-level linear growth models to specify BMI trajectories.
RESULTS: Mothers' education was inversely associated with BMI and BMI change among women. Among men, mothers' education was inversely associated with BMI; these educational disparities persisted for whites, diminished for blacks, and widened for Hispanics. Respondents' education was inversely associated with BMI among women, but was positively associated with the rate of BMI change among black women. Respondents' education was inversely associated with BMI among white and Hispanic men, and positively associated with BMI among black men. These educational disparities widened for White and Black men, but narrowed for Hispanic men.
CONCLUSIONS: Our results suggest that by simultaneously considering multiple sources of stratification, we can more fully understand how the unequal distribution of advantages or disadvantages across social groups affects BMI across the life course.