Lifecourse Socioeconomic Position and Racial Disparities in BMI Trajectories among Black and White Women: Exploring Cohort Effects in the Americans Changing Lives' Study.

Abstract

Few studies have analyzed the cohort effects of lifecourse socioeconomic position (SEP) on racial disparities in body mass index (BMI) trajectories. We assessed the contribution of lifecourse SEP on racial differences in BMI trajectories among two different age cohorts of women. Four waves of the Americans' Changing Lives' study (1986-2002) were used to compute BMI trajectories for 2194 Black and White women. Multivariable associations of lifecourse SEP variables (father's education, perceived childhood family status, education, income, wealth and financial security) with Wave 1(W1) BMI and BMI change were assessed using mixed models. Black women had higher W1 BMI than White women in both cohorts (women <40 years in 1986 (+2.6 kg/m2 (95%CI: +1.71, +3.53)) and women>=40 in 1986 (+2.68 kg/m2 (95%CI:+2.12,3.24))); Black women in the younger cohort had a higher change in BMI (+0.73 kg/m2/year (95%CI:+0.17,+1.29)). High education was associated with lower W1 BMI in both cohorts (-1.34 (95%CI:-2.53,-0.15) and -1.08 kg/m2 (95%CI:-0.50,-1.65), respectively). Among the younger cohort, high income was associated with lower W1 BMI (-0.78kg/m2/unit log income (95%CI:-1.32,-0.25)) while among the older cohort, high father's education (-0.78 kg/m2 (95%CI:-0.06,-1.50)) and higher wealth (-0.26 kg/m2(95%CI:-0.43,-0.08))were associated with low W1 BMI. Racial disparities in W1 BMI were attenuated by 20-25% while those for BMI change remained unexplained on adjustment for lifecourse SEP. In this large population-based dataset, results suggest that the contribution of lifecourse SEP to racial disparities in BMI may be established early in adulthood.