Heart Disease Among Asian Indians
- Asian Indians develop premature CAD (coronary artery disease) at a very young age, lower body mass index (BMI), and lower waist circumference. Traditional risk factors for CAD have consistently failed to completely explain this Asian Indian paradox. (Figure 003)
- Numerous studies in the past decade indicate that elevated blood level lipoprotein(a) (Lp(a)) confers genetic predisposition to CAD in Asian Indians, and nutritional and environmental factors further increase the risk of CAD.1-3
- Enas et al4 were the first to report high levels of Lp(a) in Asian Indians in the CADI Study.4 Asian Indians have Lp(a) levels intermediate between whites and blacks. However, blacks have a lower rate of CAD despite having the highest levels of Lp(a), which appears to be due to the presence of less dangerous large isoforms and high HDL levels.1, 5, 6
- Numerous studies since then have consistently reported elevated Lp(a) levels in Asian Indians in the US,7 Canada,8 Singapore,9 UK,10 Australia, and India, regardless of their migration status.1, 2, 9, 11-19 A genetic determination of Lp(a) levels in Asian Indians is strongly supported by identical Lp(a) levels in several countries, with an approximate median level of 20 mg/dL.
- In the U.K, Lp(a) levels in Asian Indians are significantly higher than whites but identical to their siblings living in India.13Also, Asian Indians with CAD and their offspring in the U.K. had higher Lp(a) levels than white CAD patients and their offspring.20
- Numerous case control and angiographic studies have shown Lp(a) to be a powerful risk factor for premature CAD and stroke among Asian Indians.2, 11, 12, 21-25
- Lipoprotein(a) level is one of the few risk factors that is highly correlated with angiographic severity of CAD in Indians.26, 27
- More than 10 angiographic and case-control studies in India have shown elevated Lp(a) levels to be the most powerful risk factor for premature CAD, especially in those younger than 40 years of age.3, 12
- Blood level of Lp(a) is an independent risk factor for clinical and subclinical heart disease in diabetic patients in India.14, 28
- Small Lp(a) isoforms are more common and strongly correlated with CAD and the risk is further increased with low HDL. Low HDL is found in 92% of Indians and the combination of high Lp(a) and low HDL2b is found in 42% of Indians.2, 29, 30
- The combination of high levels of Lp(a) and homocysteine, and high prevalence of diabetes, metabolic syndrome, and Asian Indian dyslipidemia— and the synergistic interaction among these risk factors—best explains the high prevalence of premature, severe, diffuse, multi-vessel malignant CAD among Indians globally.3, 31, 32
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