Abstract P191: Does ApoB/A1 Ratio Explain the Increased Risk of Cardiovascular Disease in Indian Asians Compared to Europeans?

Abstract

Introduction Coronary heart disease (CHD) mortality is ∼2-fold higher in Indian Asians (IA) than in European Whites (EW). This is not accounted for by conventional CHD risk factors (type-2 diabetes, cigarette smoking, hypertension, obesity, total or HDL cholesterol). The INTERHEART Study has reported that ApoB/A1 ratio is the single strongest risk factor for CHD accounting for ∼50% of CHD risk; the contribution of ApoB/A1 ratio to the excess CHD risk in IA is not known. Hypothesis We tested the hypothesis that ApoB/A1 ratio is higher in IA than EW and accounts for the ∼2-fold excess CHD risk in IA, independent of conventional CHD risk factors. Methodology We studied 1361 IA and 1028 EW men and women aged 35-75 years, participating in the London Life Sciences Population Study. All participants completed a structured health questionnaire and had blood pressure, height, weight, waist-hip ratio, fasting biochemistry measured. Coronary artery calcium (CAC) was measured by electron beam CT; Agatston score >0 was considered to indicate the presence of coronary atherosclerosis. Results Compared to EW, IA were younger, had higher prevalence of diabetes and hypertension, had higher WHR, and were less likely to smoke. Total and HDL cholesterol were lower, but Total-HDL cholesterol ratio was higher in IA ( table ). ApoB/A1 ratio was higher in IA compared to EW [0.71±0.15 vs. 0.67±0.16, p<0.001], and was independent of conventional CHD risk factors (p<0.001). In univariate analysis, ApoB/A1 ratio was associated with CAC in both populations [Odds ratio (OR) for CAC per 1 SD increase in ApoB/A1 ratio: IA 1.17 (1.05-1.30), p=0.006; EW 1.40 (1.23-1.59), p<0.001]. After adjustment for age, gender, and total-HDL cholesterol ratio, there was no association between ApoB/A1 ratio and CAC [OR: IA 0.95 (0.74-1.21), p=0.66; EW 0.98 (0.72-1.33), p=0.88]. Conclusions ApoB/A1 is higher in IA compared to EW, but not independently associated with coronary calcification in either population. ApoB/A1 ratio does not explain the ∼2-fold increased risk of CHD in IA. Europeans Indian Asians P-value N 1028 1361 Age (years) 55.5 54.2 0.002 Male gender (%) 70.3 62.0 <0.0001 Ever Smoked (%) 54.8 15.1 <0.0001 ApoB/A1 ratio 0.67 (0.16) 0.71 (0.15) <0.0001 Total: HDL Cholesterol Ratio 4.12 (1.10) 4.23 (1.03) <0.0001 HDL cholesterol (mmol/L) 1.37 (0.39) 1.24 (0.32) <0.0001 Type-2 Diabetes (%) 8.2 20.1 <0.0001 Treated Hypertension (%) 19.2 31.3 <0.0001 Waist-Hip Ratio 0.92 (0.08) 0.94 (0.08) <0.0001 Coronary artery calcium score greater than 0 (%) 54.1 51.1 0.15 Table: Characteristics of study participants