Incidence of diabetes and prediabetes and predictors of glycemic change among South Asians in the USA: the MASALA study

INTRODUCTION: South Asians have a high prevalence of type 2 diabetes mellitus (T2DM). This may be associated with high rates of conversion through the natural history of disease. However, there is a paucity of data on prediabetes and T2DM incidence and related predictors in South Asians in the USA. RESEARCH DESIGN AND METHODS: We estimated prediabetes and T2DM incidence after 5 years of follow-up in the Mediators of Atherosclerosis in South Asians Living in America study (n=481) and examined the associated correlates. We defined T2DM and prediabetes using the American Diabetes Association criteria. Prediabetes included isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT) and combined IFG and IGT. RESULTS: Overall, 152 (32%, 95% CI: 27.6 to 35.9) individuals progressed either from normal glucose tolerance to prediabetes or T2DM, or from prediabetes to T2DM. In standardised logistic regression models controlling for age and sex, only hepatic fat attenuation (increased hepatic fat) (OR: 0.67 (95% CI: 0.55 to 0.87) per SD, visceral fat area (OR: 1.36 (95% CI: 1.06 to 1.74) per SD and hypertension (OR: 2.21 (95% CI: 1.44 to 3.40) were associated with any glycemic progression. CONCLUSIONS: South Asians in the USA have a high incidence of dysglycemia. Hepatic and visceral fat may be factors in glycemic progression, and prevention efforts should target ectopic fat reduction.