Racial and ethnic disparities in type 2 diabetes: does visceral fat play a role? Evidence from the MESA study

Objective In the United States, racial and ethnic minorities have higher risk of developing type 2 diabetes (T2D) than Whites. One hypothesis is that some minorities (e.g., Hispanics, Asians) have more visceral fat than Whites in a sex-specific manner. We aimed to test this hypothesis by examining to what degree racial differences in T2D were explained by visceral fat in males and females. Methods This prospective cohort included 1457 participants (51.2% females) from the Multi-Ethnic Study of Atherosclerosis (MESA) cohort who had visceral fat measured by computed tomography and followed for incident T2D from 2002–2005 to 2020. We assessed associations of race and T2D risk using Cox proportional hazards regressions and estimated associations explained by visceral fat using natural mediation effects, stratified by sex. Results Controlling for confounders, compared with White participants, T2D risk was higher in Hispanic females (HR 1.77, 95% CI 1.17–2.69), Chinese females (1.91, 1.15–3.15), Black females (1.59, 1.02–2.49), and Hispanic males (1.82, 1.20–2.76). Estimates for Black males (1.48, 0.92–2.38) and Chinese males (0.86, 0.48–1.55) were not statistically significant. By sex, Hispanic females [mean difference (SE): 22.72 (5.68)] had higher visceral fat (cm 2 ) than White females, while Chinese [−77.56 (8.47)] and Black [−57.57 (8.11)] males had lower visceral fat (cm 2 ) than White males. Visceral fat explained 23.1% of T2D risk between Hispanic and White females, but not for other racial and sex subgroups. Conclusion Visceral fat explained one-fifth of racial and ethnic differences in T2D comparing Hispanic females to White females and may contribute to Hispanic females’ higher T2D risk.