Coronary risk in South Asians: role of ethnicity and blood sugar

Background Studies of South Asian immigrants in different countries have reported an increased predisposition to cardiovascular disease in comparison with the native populations. Design This study is a systematic review of longitudinal studies investigating differences in established risk factors for coronary heart disease (CHD) between Caucasians and South Asians. The aim was to develop a practical tool to estimate CHD risk in individuals. Secondarily data from the Health Survey for England 1999 (HSE 1999) were used to explore a possible role of differences in blood glucose in risk variation. Methods We used a systematic search to find relevant published papers. Data from the HSE 1999 were employed to study ethnic differences in blood glucose and glycosylated haemoglobin. Results Only two out of five longitudinal studies reported independent estimates of relative risks of CHD in South Asians compared to Caucasians. Risk in diabetic South Asians was predicted adequately by classical risk factors whilst risk in a non-diabetic study population was 79% greater than predicted. Non-diabetic South Asians have higher fasting blood glucose (FBG) and HbA(1c) than Caucasians after adjustment for CHD risk factors. Conclusions The difference in risk of CHD between non-diabetic South Asian and Caucasians is not explained by differences in the impact of the traditional risk factors. Part may be due to higher blood sugar concentrations in nondiabetic South Asians. (C) 2004 The European Society of Cardiology