Lipoprotein (a) and aortic valve calcium in South Asians compared to other race/ethnic groups

Background and aims: South Asians are at increased risk for cardiovascular disease (CVD). Aortic valve calcium (AVC) is associated with CVD risk and aortic stenosis. Elevated Lp(a) is a heritable risk factor for CVD and AVC. AVC prevalence and its association with Lp(a) have not been studied in South Asians. Methods: Among participants in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study (n = 695), AVC prevalence and extent were compared to four race/ethnic groups in the Multi-Ethnic Study of Atherosclerosis (MESA) (n = 4671). Multivariable regression was performed to evaluate associations between Lp(a) and AVC stratified by race/ethnic groups, adjusting for cardiovascular risk factors. Results: After age and sex adjustment, South Asians had higher median Lp(a) (17.0 mg/dL) compared to Whites (12.9 mg/dL), Hispanics (13.1 mg/dL) and Chinese Americans (12.9 mg/dL), and Blacks had highest Lp(a) levels (35.1 mg/dL). There were no differences in the odds of AVC in South Asians compared with Whites or Hispanics, after age and sex adjustment (p = 0.64 and 0.63, respectively). Odds of AVC was lower in Chinese (OR 0.35; 95% CI 0.23-0.54) and somewhat lower in Blacks compared with South Asians (OR 0.76; 0.56-1.04). There were no associations between Lp(a) and AVC presence or extent in South Asians. Lp(a) was associated with AVC only among Blacks and Whites. Conclusions: Although present in Whites and Blacks, there were no associations between Lp(a) and AVC in South Asians. These differences may be due to statistic power or race specific modifying factors that influences the effect of Lp(a) particles on AVC pathogenesis.