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 in the U.S. Racial and ethnic minorities have a higher risk of Type 2 diabetes, and studies suggest that they engage in less exercise than White population. This study examined whether and to what degree racial differences in Type 2 diabetes were explained by exercise. Methods: Adults aged 45-84 years without Type 2 diabetes at baseline (2000-2002) were included from the Multi-Ethnic Study of Atherosclerosis cohort and followed through 2020. Associations between race and Type 2 diabetes were examined using multivariable Cox proportional hazard regression. The effects of exercise were assessed using natural mediation effects. Analyses were conducted in 2023. Results: Controlling for confounders, Hispanic (adjusted hazard ratio [95% CI]=2.02 [1.74, 2.34]), Chinese (1.50 [1.24, 1.82]), and Black (1.66 [1.44, 1.93]) participants had higher Type 2 diabetes risks than White participants. Hispanic (b [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 than White participants; this was not true for Black participants (-0.01 [0.03], p=0.85). Habitual intentional exercise explained Type 2 diabetes excess risk by 13.6% for Hispanic and 13.2% for Chinese participants but not for Black participants, compared with that for White participants. Conclusions: Habitual intentional exercise accounted for one tenth of the racial differences in Type 2 diabetes when comparing Hispanic or Chinese populations with White populations. Interventions promoting exercise are crucial to decrease Type 2 diabetes risk for all racial groups but may also narrow disparities in Type 2 diabetes among Hispanic and Chinese populations.