Ischemic stroke in South Asians: the BRAINS study

Background Studies on stroke in South Asians are sparse. We compared differences in age of onset of ischemic stroke in South Asians living in the UK and those in India with white British stroke patients. Methods We studied the UK and Indian arms of the ongoing international prospective hospital-based study of South Asian stroke (BRAINS study). BRAINS includes 4038 South Asian and white British recruits from UK and Indian sites with first-ever ischemic stroke. Results Of included patients, 1126 were South Asians in India (ISA); 1176 British South Asians (BSA), and: 1736 white British (WB) UK residents. ISA and BSA South Asians suffered stroke 19.5 years and 7.2 years earlier than their WB counterparts, respectively (BSA: 64.3 years IQR: 22 years, vs. ISA: 52.0 years IQR: 18 years, vs. WB: 71.5 years IQR: 19 years, P<0.001). BSA had higher rates of hypertension, diabetes-mellitus and hypercholesterolaemia than ISA and WB stroke victims. Adjusting for traditional stroke risk factors, ISA and BSA continued to display an earlier age of stroke onset of 18.9 years (P<0.001) and 8.9 years (P<0.001), respectively. Following multivariable stepwise linear regression ethnicity accounted for 24.7% of variance of early age onset. Conclusion South Asians living in the UK (BSA) and those living in India (ISA) suffered ischemic stroke ~9 and ~19 years earlier respectively than their white British (WB) counterparts. Ethnicity is an independent predictor of early age onset. Our study has considerable implications for public health policymakers in countries with sizable South Asian populations.