Racial disparities of type 2 diabetes through exercise: The Multi-Ethnic Study of Atherosclerosis.

Introduction: Persistent racial and ethnic disparities exist for type 2 diabetes (T2D) in the United States. Racial and ethnic minorities have higher T2D risk and studies suggest they engage in less exercise than Whites. This study examined whether, and to what degree, racial differences in T2D were explained by exercise.

Methods: Adults aged 45-84 years without T2D at baseline (2000-2002) were included from the Multi-Ethnic Study of Atherosclerosis (MESA) cohort and followed through 2020. Associations of race with T2D were examined using multivariable Cox proportional hazards regressions. Effects explained by exercise were assessed using natural mediation effects. Analyses were conducted in 2023.

Results: Controlling for confounders, Hispanic [adjusted hazard ratio (HR) (95% confidence interval, CI): 2.02 (1.74-2.34)], Chinese [1.50 (1.24-1.82)], and Black participants [1.66 (1.44-1.93)] had higher T2D risks than White participants. Compared with White participants, Hispanic [β (SE): -0.29 (0.04) square root of MET-hour/day, P < 0.001] and Chinese [-0.25 (0.04), P < 0.001] participants had lower habitual intentional exercise, this was not true for Black participants [-0.01 (0.03), P = 0.85]. Habitual intentional exercise explained T2D relative risk by 13.6% for Hispanic and 13.2% for Chinese, but did not explain for Black participants, compared with White participants.

Conclusions: Habitual intentional exercise accounted for one-tenth of racial differences in T2D when comparing Hispanic or Chinese populations with White populations. Interventions promoting exercise are crucial to decrease T2D risk for all racial groups but may additionally narrow disparities in T2D among Hispanic and Chinese populations.