Coronary artery diseases in South Asian immigrants: an update on high density lipoprotein role in disease prevention

Genetic and Non-genetic Determinants of Cardiovascular Disease in South Asians

South Asians (SAs), people from the Indian subcontinent (e.g., India, Pakistan, Bangladesh, Sri Lanka, and Nepal) have a higher prevalence of cardiovascular disease (CVD) and suffer from a greater risk of CVD-associated mortality compared to other global populations. These problems are compounded by the alterations in lifestyles due to urbanization and changing cultural, social, economic, and political environments. Current methods of CV risk prediction are based on white populations that under-estimate the CVD risk in SAs. Prospective studies are required to obtain actual CVD morbidity/mortality rates so that comparisons between predicted CVD risk can be made with actual events. Overwhelming data support a strong influence of genetic factors. Genome-Wide Association Studies (GWAS) serve as a starting point for future genetic and functional studies since the mechanisms of action by which these associated loci influence CVD is still unclear. It is difficult to predict the potential implication of these findings in clinical settings. This review provides a systematic assessment of the risk factors, genetics, and environmental causes of CV health disparity in SAs, and highlights progress made in clinical and genomics discoveries in the rapidly evolving field, which has the potential to show clinical relevance in the near future.

Nutritional Therapy for Asian Patients at Risk for Atherosclerotic Cardiovascular Disease

The burden of atherosclerotic cardiovascular disease (ASCVD) remains high worldwide, and its prevalence has increased in Asian countries over the last two decades. The increase in ASCVD may arise from complex interactions between genetic and lifestyle/environmental factors. Abnormal blood cholesterol levels, elevated blood glucose, obesity, elevated blood pressure, smoking, and family history are common risk factors of ASCVD. There is an increased burden of ASCVD in Asian countries, maybe due to rapid economic development and lifestyle changes in these countries. Nutrition is one of the major modifiable risk factors for ASCVD. Despite this, there are insufficient nutritional therapies for prevention and management of ASCVD in Asian patients. There is also a lack of relevant research in Asian populations. In this review, we describe the current nutritional guidelines and the findings from previous landmark studies regarding management and/or prevention of ASCVD. We also summarize the recommendations regarding evidence-based nutrition therapy/management strategies that may be effective in Asian subjects to prevent onset and/or to treat ASCVD.

Ethnicity and coronary artery disease: the role of high-density lipoprotein - a change in paradigm

Cardiovascular disease (CVD) is the number one killer of men and women across ethnic groups in the USA. Health disparities in CVD, especially coronary artery disease (CAD), are well documented in the diverse American population. Despite efforts taken toward reducing cardiovascular health disparities, there are still gaps in its diagnosis and management. Current risk assessment guidelines consider high high-density lipoprotein (HDL) levels a protective factor against CAD, although its significance across races remains poorly understood. Recent clinical trials focused on increasing HDL levels have been disappointing. In this article, the authors have explored the role of HDL in CAD, have analyzed its significance across gender and ethnic groups and have challenged the broad application of widely used HDL level cutoffs in CAD risk assessment tools across these vulnerable groups. The current evidence suggests a paradigm change from HDL quantity to quality and function in future CVD risk research. This may better explain why some ethnic minority groups with a seemingly more benign lipid profile experience a higher CAD burden.

Metabolic syndrome among Sri Lankan adults: prevalence, patterns and correlates

Metabolic Syndrome (MS) increases the risk for Coronary Artery Disease, stroke and diabetes. MS is twice more common amongst South Asian immigrants in US compared to native Caucasians. There are no nationally representative studies on prevalence of MS from any of the South Asian countries. The present study aims to evaluate the prevalence of MS among Sri Lankan adults and investigates its relationships with socio-demographic, clinical and biochemical parameters. Data on MS and its associated details were obtained from a population-based cross-sectional study conducted between years 2005-2006. MS was defined according to the International Diabetes Federation criteria. A binary logistic regression analysis was performed using the dichotomous variable MS (0 = absent, 1 = present). The independent co-variants were: gender, age category, area of residence, ethnicity, level of education, income and physical activity. Sample size was 4,485 (Response rate-89.7%), 39.5% were males and mean age was 46.1 ± 15.1 years. The crude prevalence of MS was 27.1% (95% CI: 25.8-28.5), and age-adjusted prevalence was 24.3% (95% CI: 23.0-25.6). Prevalence in males and females were 18.4% (95% CI: 16.5-20.3) and 28.3% (95% CI: 26.6-30.0) respectively (p < 0.001). Urban adults (34.8% [95% CI: 31.8-37.9]) had a significantly higher prevalence than rural adults (21.6% [95% CI: 20.2-23.0]). Among ethnic groups, the highest prevalence of MS was observed in Sri Lankan Moors (43.0% [95% CI: 37.2-48.9]). In all adults, MS was observed in those with the highest level of education and monthly household income. Prevalence of MS in the different physical activity categories of the IPAQ were; 'inactive'-38.8% (95% CI 34.5-43.2), 'moderately active'-33.5% (95% CI 30.9-36.1) and 'active'-21.1% (95% CI 19.6-22.7). The results of the binary logistic regression analysis indicates that female gender (OR:1.7), increasing age, urban living (OR:1.7), Moor ethnicity (OR:2.6), secondary (OR:1.5) and tertiary levels of education (OR:2.3), monthly household income LKR 7,000-24,999 (OR:1.5) and >50,000 (OR:2.1), and physical inactivity (OR:1.6), all significantly increased risk of developing MS. MS is common among Sri Lankan adults affecting nearly one-fourth of the population. Female gender, increasing age, urban living, higher socio-economical status and physical inactivity were important associated factors.

Metabolic syndrome in South Asian immigrants: more than low HDL requiring aggressive management

Aggressive clinical and public health interventions have resulted in significant reduction in coronary artery disease (CAD) worldwide. However, South Asian immigrants (SAIs) exhibit the higher prevalence of CAD and its risk factors as compared with other ethnic populations. The objective of the current study is to assess the prevalence of metabolic syndrome (MS), its association with high density Lipoprotein (HDL) function, Apo lipoprotein A-I (APOA1) gene polymorphisms, and sub-clinical CAD using common carotid intima-media thickness (CCA-IMT) as a surrogate marker. A community-based cross-sectional study was conducted on SAIs aged 35-65 years. Dysfunctional/pro-inflammatory (Dys-HDL) was determined using novel cell free assay and HDL inflammatory index. Six intronic APOA1 gene polymorphisms were analyzed by DNA sequencing. According to the International Diabetes Federation definition, MS prevalence was 29.7% in SAIs without CAD and 26% had HDL inflammatory index ≥ 1 suggesting pro-inflammatory Dys-HDL. Six novel APOA1 single nucleotide polymorphisms (SNPs) were analyzed with logistic regression, three SNPs (G2, G3, and G5) were found to be significantly associated with MS (p = 0.039, p = 0.038, p = 0.054). On multi-variate analysis, MS was significantly associated with BMI > 23 (P = 0.005), Apo-A-I levels (p = 0.01), and Lp [a] (p < 0.0001). SAIs are known to be at a disproportionately high risk for CAD that may be attributed to a high burden for MS. There is need to explore and understand non-traditional risk factors with special focus on Dys-HDL, knowing that SAIs have low HDL levels. Large prospective studies are needed to further strengthen current study results.