The increased risk of microvascular complications in South Asians with type 1 diabetes is influenced by migration

We aimed to explore the association between South Asian ethnicity and complications of type 1 diabetes, and whether this is affected by migration.

In this retrospective cohort study, data on diabetes control and complications were obtained for South Asians in India (South Asians_India , n = 2592) and the UK (South Asians_UK , n = 221) and white Europeans in the UK (n = 1431). Multivariable logistic regression was used to identify associations between ethnicity and diabetic kidney disease, retinopathy and neuropathy adjusting for age, sex, BMI, disease duration, HbA_1c , blood pressure (BP) and cholesterol.

South Asians_India had significantly greater adjusted odds of diabetic kidney disease [odds ratio (OR) 5.0, 95% confidence intervals (CI) 3.6-7.1] and retinopathy (OR 1.8, 95% CI 1.2-2.5), but lower odds of neuropathy (OR 0.5, 95% CI 0.4-0.6) than white Europeans. South Asians_India had significantly greater adjusted odds of diabetic kidney disease (OR 3.0, 95% 1.8-5.3) than South Asians_UK , but there was no significant difference in the odds of other complications.

In this hypothesis-generating study, we report that South Asian ethnicity is associated with greater risk of diabetic kidney disease and retinopathy, and lower risk of neuropathy than white European ethnicity. Part of the excess diabetic kidney disease risk is reduced in South Asians_UK . These associations cannot be accounted for by differences in vascular risk factors. Our findings in South Asians with type 1 diabetes mirror previous findings in type 2 diabetes and now need to be validated in a study of the effect of ethnicity on type 1 diabetes complications where healthcare is provided in the same setting.