Sex Differences in Factors Contributing to the Racial Disparity in Diabetes Risk.

Introduction: Diabetes incidence differs by race in the U.S., with a persistent reported Black-White disparity. However, the factors that contribute to this excess risk in middle-aged and older adults are unclear.

Methods: This prospective cohort study included 7,171 Black and White adults aged ≥45 years without diabetes at baseline (2003‒2007) who completed a follow-up examination (2013‒2016). Modified Poisson regression was used to obtain sex-stratified RRs for diabetes. Mediation analyses using a change in β coefficient assessed individual and neighborhood factors that contribute to the racial disparity in diabetes incidence. Statistical analyses were conducted in 2018-2019.

Results: The cumulative incidence of diabetes was higher for Black men (16.2%) and women (17.7%) than for White men (11.0%) and women (8.1%). Adjusting for age and prediabetes, diabetes risk was higher for Black women than for White women (RR=1.75, 95% CI=1.47, 2.07) and for Black men than for White men (RR=1.33, 95% CI=1.09, 1.64). The individual factors that attenuated the racial disparity the most were Southern dietary pattern (change in β=42.8%) and neighborhood socioeconomic environment (change in β=26.3%) among men and BMI (change in β=34.4%) and waist circumference (change in β=32.4%) among women. When including all factors collectively, the racial disparity in diabetes incidence was similar for men (RR=1.38, 95% CI=1.04, 1.83) and was attenuated for women (RR=1.41, 95% CI=1.11, 1.81).

Conclusions: The racial disparity in diabetes incidence remained after accounting for individual and neighborhood factors. Further investigation of additional factors underlying this racial disparity is needed to inform multilevel strategies for diabetes prevention.