Abstract
Background: Coronary heart disease (CHD) mortality is 70% higher among UK Indian Asian than white Europeans. Currently available risk stratification tools and biomarkers do not allow the accurate identification of Indian Asians at increased risk of CHD. Coronary artery calcification (CAC) is highly correlated with coronary plaque burden and is an independent predictor of future CHD events in north American and European white populations. We hypothesised that CAC is increased in Indian Asians compared with white Europeans and may provide a non-invasive tool for the assessment of CHD risk in Indian Asians. Methods: We investigated 2398 Indian Asian and white European men and women, aged 35–75 years (Indian Asians: 837 men, 530 women; white European: 722 men, 309 women). Participants were recruited from the practice lists of 58 general practitioners in west London, as part of the London Life Sciences Population (LOLIPOP) study and all were free form clinical cardiovascular disease. CAC was measured for all participants using an electron beam computed tomography scanner (Imatron C-150 (modified), General Electric). Participants were also characterised for cardiovascular risk factors. Results: In comparison with Europeans, Indian Asians had an approximately twofold higher prevalence of hypertension and type 2 diabetes, higher waist–hip ratio and triglycerides, and lower high-density lipoprotein cholesterol (table). Cigarette smoking and cholesterol levels were lower in Indian Asians compared with white Europeans. CAC was more common in men than women, and CAC scores were closely associated with cardiovascular risk factors including age, cigarette smoking, hypertension, diabetes, total cholesterol and metabolic syndrome (all p<0.05). In contrast, there was no difference in CAC prevalence or mean levels of CAC between Indian Asians and Europeans either before or after adjustment for the measured cardiovascular risk factors (fig). Summary: CAC is not increased in Indian Asians compared with white Europeans, in any age group or in either gender. Similar CAC in Indian Asians and Europeans contrasts with an almost twofold higher risk of myocardial infarction and CHD mortality in Asians. CAC does not predict or identify the excess CHD risk in Indian Asians.