Risk of coronary disease in the South Asian American population

Association of cardiovascular health with subclinical coronary atherosclerosis progression among five racial and ethnic groups: The MASALA and MESA studies

BACKGROUND AND AIMS

South Asian adults (SA) are at higher risk for atherosclerotic cardiovascular disease (ASCVD) compared with other racial/ethnic groups. Life's Simple 7 (LS7) is a guideline-recommended, cardiovascular health (CVH) construct to guide optimization of cardiovascular risk factors. We sought to assess if the LS7 metrics predict coronary artery calcium (CAC) incidence and progression in asymptomatic SA compared with four other racial/ethnic groups.

METHODS

We assessed the distribution of CVH metrics (inadequate: score 0-8, average: 9-10, optimal: 11-14, and per 1-unit higher score) and its association with incidence and progression of CAC among South Asians in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study compared with other race/ethnic groups from the Multiethnic Study of Atherosclerosis (MESA).

RESULTS

We included 810 SA, 2622 Non-Hispanic White (NHW), and 4192 Other adults (collectively 1893 Black, 1496 Hispanic and 803 Chinese American participants, respectively). SA and White participants compared to Other race/ethnicity groups were more likely to have optimal CVH metrics (26% SA vs 28% White participants vs 21% Other, respectively, p < 0.001). Similar to NHW and the Other race/ethnic group, SA participants with optimal baseline CVH were less likely to develop incident CAC on follow-up evaluation compared to participants with inadequate CVH metrics, optimal CVH/CAC = 0: 24% SA, 28% NHW, and 15% Other (p < 0.01). In multivariable linear and logistic regression models, there was no difference in annualized CAC incidence or progression between each race/ethnic group (pinteraction = 0.85 and pinteraction = 0.17, respectively). Optimal blood pressure control was associated with lower CAC incidence among SA participants [OR (95% CI): 0.30 (0.14-0.63), p < 0.01] and Other race and ethnicity participants [0.32 (0.19-0.53), p < 0.01].

CONCLUSIONS

Optimal CVH metrics are associated with lower incident CAC and CAC progression among South Asians, similar to other racial groups/ethnicities. These findings underscore the importance of optimizing and maintaining CVH to mitigate the future risk of subclinical atherosclerosis in this higher risk population.

Comparing coronary artery cross-sectional area among asymptomatic South Asian, White, and Black participants: the MASALA and CARDIA studies

BACKGROUND

South Asian individuals have high risk of atherosclerotic cardiovascular disease (ASCVD). Some investigators suggest smaller coronary artery size may be partially responsible.

METHODS

We compared the left anterior descending (LAD) artery cross-sectional area (CSA) (lumen and arterial wall) among South Asians in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study with White and Black participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study, adjusting for BMI, height, and other ASCVD risk factors. We used thin-slice non-contrast cardiac computed tomography to measure LAD CSA. We used linear regression models to determine whether race/ethnicity was associated with LAD CSA after adjusting for demographic factors, BMI, height, coronary artery calcium (CAC), and traditional cardiovascular risk factors.

RESULTS

Our sample included 3,353 participants: 513 self-identified as South Asian (44.4% women), 1286 as Black (59.6% women), and 1554 as White (53.5% women). After adjusting for age, BMI, height, there was no difference in LAD CSA between South Asian men and women compared to White men and women, respectively. After full adjustment for CVD risk factors, LAD CSA values were: South Asian women (19.9 mm2, 95% CI [18.8 - 20.9]) and men (22.3 mm2, 95% CI [21.4 - 23.2]; White women (20.0 mm2, 95% CI [19.4-20.5]) and men (23.6 mm2, 95% CI [23.0-24.2]); and Black women (21.6 mm2, 95% CI [21.0 - 22.2]) and men (26.0 mm2, 95% CI [25.3 - 26.7]). Height, BMI, hypertension, CAC, and age were positively associated with LAD CSA; current and former cigarette use were inversely associated.

CONCLUSIONS

South Asian men and women have similar LAD CSA to White men and women, and smaller LAD CSA compared to Black men and women, respectively, after accounting for differences in body size. Future studies should determine whether LAD CSA is associated with future ASCVD events.

Prevalence of polycystic ovary syndrome and its clinical and hormonal profile in young females with type 1 diabetes mellitus: experience from a teaching institution of India

OBJECTIVE

To investigate the prevalence of polycystic ovary syndrome and its clinical and hormonal profile in females with type 1 diabetes.

MATERIALS AND METHODS

65 T1DM females were evaluated for presence of PCOS by Rotterdam ESHRE/ASRM consensus criteria and compared with age and BMI matched females with PCOS without diabetes and females with T1DM without PCOS.

RESULTS

According to Rotterdam criteria 18/65 (27%) had PCOS. Prevalence of androgen excess, hirsutism, menstrual dysfunction and PCOM was 26%, 3%, 21% and 52%, respectively. Females with T1DM who had PCOS did not differ from females with T1DM without PCOS. When the group of T1DM with PCOS was compared with PCOS females without diabetes, they had significantly lower hirsutism score (median, IQR; 1.5, 0-3 vs. 11.5, 0-16.5, p = 0.04), significantly higher waist hip ratio (0.91, 0.89-0.99 vs. 0.86, 0.80-0.89, p = 0.004) and SHBG (in nmol, 54.4, 38-86.2 vs. 28.3, 20.4-37.4, p = 0.004).

CONCLUSION

Females with T1DM have a high prevalence of menstrual abnormalities, hyperandrogenism and PCOS which is not related to metabolic control, age of onset of diabetes or insulin dose. Polycystic ovary syndrome, hyperandrogenism, type 1 diabetes, menstrual irregularity, hirsutism.

Development of a Food List to Assess the Diet of South Asians Living in the U.S.: Preliminary Results From a Formative Study

Introduction

South Asians are an underrepresented population subgroup in the U.S., yet they have higher rates of chronic diseases. There is currently no tool that assesses the nutrition intake of South Asians in the U.S., despite their unique dietary profile that may be associated with disease outcomes. The objective of this preliminary study was to create a food list, inclusive of herbs and spices, that will be used in the development of the web-based South Asian Food Intake System for dietary assessment of South Asian adults living in the U.S.

Methods

Authors used a Qualtrics survey to collect sociodemographic information (n=66), and 24-hour diet recall and Home Food Inventory interviews were conducted through Zoom (n=31). Grocery store tours and cookbook and existing food frequency questionnaire review were conducted.

Results

A food list of 484 individual food items was generated. These items were sorted into 12 main food categories and condensed into 302 line items. Most respondents (68%) reported consuming South Asian meals regularly and utilizing herbs/spices during food preparation (83%).

Conclusions

This pilot study describes the data collection to develop a food list for the South Asian Food Intake System, which can be utilized by educators, clinicians, and researchers to more accurately collect information about dietary intake among South Asian Americans.

Heightened risks of cardiovascular disease in South Asian populations: causes and consequences

INTRODUCTION

South Asian individuals comprise almost a quarter of the world's population and have an excess risk of atherosclerotic cardiovascular disease (ASCVD) compared to other ethnicities. In part, this can be explained by higher prevalence, earlier onset, and suboptimal control of traditional cardiovascular risk factors, such as insulin resistance, metabolic syndrome, and dyslipidaemia. However, there remains a significant residual excess risk associated with South Asian ethnicity after controlling for traditional risk factors.

AREAS COVERED

In this review, we describe the epidemiology of ASCVD in both native and diaspora South Asian populations. We explore how traditional cardiovascular risk factors, novel cardiovascular risk factors, and social determinants of health may contribute to the excess ASCVD risk seen in South Asian populations.

EXPERT OPINION

There should be increased awareness of the relative importance of South Asian ethnicity and related social determinants of health, as risk factors for ASCVD. Systematic screening processes should be tailored to this population, and modifiable risk factors should be treated aggressively. Further research is required to quantify determinants of the excess ASCVD risk seen in South Asian populations and to develop targeted interventions to address these factors.

Metabolic Syndrome and Chronic Disease Risk in South Asian Immigrants: A Review of Prevalence, Factors, and Interventions

South Asians (SAs) are among the fastest-growing ethnic groups in the U.S. Metabolic syndrome (MetS) is a condition that is characterized by multiple health factors that increase the risk for chronic diseases, such as cardiovascular disease (CVD) and diabetes. MetS prevalence among SA immigrants ranges from 27-47% in multiple cross-sectional studies using different diagnostic criteria, which is generally higher compared to other populations in the receiving country. Both genetic and environmental factors are attributed to this increased prevalence. Limited intervention studies have shown effective management of MetS conditions within the SA population. This review reports MetS prevalence in SAs residing in non-native countries, identifies contributing factors, and discusses ways to develop effective community-based strategies for health promotion targeting MetS among SA immigrants. There is a need for more consistently evaluated longitudinal studies to facilitate the development of directed public health policy and education to address chronic diseases in the SA immigrant community.

Barriers to Follow Up Care in the South Asian Immigrant Population at High Risk of Acute Coronary Syndrome at Elmhurst Hospital Center

We studied South Asian immigrant patients who did not return to Elmhurst Hospital Center (EHC) after emergent cardiac catheterization in order to propose interventions to improve follow up care. We identified 74 eligible patients, interviewed 30 about follow up practices, and analyzed findings. Most patients are Bangladeshi and 77% preferred a foreign language. Some were visiting the US during the admission without intent to follow up. Half were dissatisfied with EHC providers, complications, and inadequate care at follow up appointments. Some patients were unaware of scheduled appointments or the necessity of follow up. Most follow with private providers due to language accessibility, availability, and proximity. We found that language barriers contribute to loss to follow up and the true loss to follow up rate is lower than reported at EHC. This can inform practices at hospitals with immigrant populations, minimize resource waste, and improve quality of care.

Implications of the 2019 American College of Cardiology/American Heart Association Primary Prevention Guidelines and potential value of the coronary artery calcium score among South Asians in the US: The Mediators of Atherosclerosis in South Asians Living in America (MASALA) study

BACKGROUND AND AIMS

South Asian (SA) ethnicity is associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). However, the implications of considering SA ethnicity as a "risk-enhancing factor" per recent American College of Cardiology/American Heart Association guidelines are not fully understood.

METHODS

We used data from the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study, a community-based cohort study of individuals of SA ancestry living in the US. The Pooled Cohort Equations were used to estimate 10-year ASCVD risk. Metabolic risk factors and coronary artery calcium (CAC) scores were assessed.

RESULTS

Among 1114 MASALA participants included (median age 56 years, 48% women), 28% were already using a statin at baseline, 25% had prevalent diabetes, and 59% qualified for 10-year ASCVD risk assessment for statin allocation purposes. The prevalence of low, borderline, intermediate, and high estimated ASCVD risk was 65%, 11%, 20% and 5%, respectively. Among participants at intermediate risk, 30% had CAC = 0 and 37% had CAC>100, while among participants at borderline risk, 54% had CAC = 0 and 13% had CAC>100. Systematic consideration of intermediate and, particularly, of borderline risk individuals as statin candidates would enrich the statin-consideration group with CAC = 0 participants up to 35%. Prediabetes and abdominal obesity were highly prevalent across all estimated risk strata, including among those with CAC = 0.

CONCLUSIONS

Our findings suggest that systematic consideration of borderline risk SAs as statin candidates might result in considerable overtreatment, and further risk assessment with CAC may help better personalize statin allocation in these individuals. Early, aggressive lifestyle interventions aimed at reducing the risk of incident diabetes should be strongly recommended in US SAs, particularly among those considered candidates for statin therapy for primary prevention. Longitudinal studies are needed to confirm the favorable prognosis of CAC = 0 in SAs.

Associations between Cumulative Biological Risk and Subclinical Atherosclerosis in Middle- and Older-Aged South Asian Immigrants in the United States

INTRODUCTION

The aim of this study was to investigate associations between cumulative biological risk and subclinical atherosclerosis in South Asian immigrants.

METHODS

Data from the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study, including 858 participants at baseline (mean age = 56 [standard deviation = 9] years, 46% women). A cumulative biological risk score was derived using nine biomarkers across cardiovascular, immune, and metabolic systems with a possible score range of 0-9. Common and internal carotid artery intima media thickness (CIMT) and coronary artery calcium (CAC) were used as indicators of subclinical atherosclerosis.

RESULTS

Higher cumulative biological risk score was significantly associated with higher common and internal CIMT and higher odds of CAC at baseline. The odds of new CAC after 5 years of follow-up were 31% higher per 1-point increase in cumulative biological risk score, and the higher cumulative biological risk score was also associated with CAC progression.

CONCLUSIONS

Among South Asian immigrants, cumulative biological risk was directly associated with subclinical atherosclerosis and its progression.

Quantifying and Understanding the Higher Risk of Atherosclerotic Cardiovascular Disease Among South Asian Individuals: Results From the UK Biobank Prospective Cohort Study

BACKGROUND

Individuals of South Asian ancestry represent 23% of the global population, corresponding to 1.8 billion people, and have substantially higher risk of atherosclerotic cardiovascular disease compared with most other ethnicities. US practice guidelines now recognize South Asian ancestry as an important risk-enhancing factor. The magnitude of enhanced risk within the context of contemporary clinical care, the extent to which it is captured by existing risk estimators, and its potential mechanisms warrant additional study.

METHODS

Within the UK Biobank prospective cohort study, 8124 middle-aged participants of South Asian ancestry and 449 349 participants of European ancestry who were free of atherosclerotic cardiovascular disease at the time of enrollment were examined. The relationship of ancestry to risk of incident atherosclerotic cardiovascular disease-defined as myocardial infarction, coronary revascularization, or ischemic stroke-was assessed with Cox proportional hazards regression, along with examination of a broad range of clinical, anthropometric, and lifestyle mediators.

RESULTS

The mean age at study enrollment was 57 years, and 202 405 (44%) were male. Over a median follow-up of 11 years, 554 of 8124 (6.8%) individuals of South Asian ancestry experienced an atherosclerotic cardiovascular disease event compared with 19 756 of 449 349 (4.4%) individuals of European ancestry, corresponding to an adjusted hazard ratio of 2.03 (95% CI, 1.86-2.22; P<0.001). This higher relative risk was largely consistent across a range of age, sex, and clinical subgroups. Despite the >2-fold higher observed risk, the predicted 10-year risk of cardiovascular disease according to the American Heart Association/American College of Cardiology Pooled Cohort equations and QRISK3 equations was nearly identical for individuals of South Asian and European ancestry. Adjustment for a broad range of clinical, anthropometric, and lifestyle risk factors led to only modest attenuation of the observed hazard ratio to 1.45 (95% CI, 1.28-1.65, P<0.001). Assessment of variance explained by 18 candidate risk factors suggested greater importance of hypertension, diabetes, and central adiposity in South Asian individuals.

CONCLUSIONS

Within a large prospective study, South Asian individuals had substantially higher risk of atherosclerotic cardiovascular disease compared with individuals of European ancestry, and this risk was not captured by the Pooled Cohort Equations.

Prevention of atherosclerotic cardiovascular disease in South Asians in the US: A clinical perspective from the National Lipid Association

It is now well recognized that South Asians living in the US (SAUS) have a higher prevalence of atherosclerotic cardiovascular disease (ASCVD) that begins earlier and is more aggressive than age-matched people of other ethnicities. SA ancestry is now recognized as a risk enhancer in the US cholesterol treatment guidelines. The pathophysiology of this is not fully understood but may relate to insulin resistance, genetic and dietary factors, lack of physical exercise, visceral adiposity and other, yet undiscovered biologic mechanisms. In this expert consensus document, we review the epidemiology of ASCVD in this population, enumerate the challenges faced in tackling this problem, provide strategies for early screening and education of the community and their healthcare providers, and offer practical prevention strategies and culturally-tailored dietary advice to lower the rates of ASCVD in this cohort.

Cardiovascular Risk Calculators and their Applicability to South Asians

BACKGROUND

Estimation of absolute cardiovascular disease (CVD) risk and tailoring therapies according to the estimated risk is a fundamental concept in the primary prevention of CVD is assessed in this study. Numerous CVD risk scores are currently available for use in various populations but unfortunately, none exist for South Asians who have much higher CVD risk as compared to their western counterparts.

METHODS

A literature search was done using PubMed and Google search engines to prepare a narrative review on this topic.

RESULTS

Various currently available CVD risk scores and their pros and cons are summarized. The studies performed in native as well as migrant South Asians evaluating the accuracy of these risk scores for estimation of CVD risk are also summarized. The findings of these studies have generally been inconsistent, but it appears that the British risk scores (e.g. QRISK versions) may be more accurate because of inclusion of migrant South Asians in the derivation of these risk scores. However, the lack of any prospective study precludes our ability to draw any firm conclusions. Finally, the potential solution to these challenges, including the role of recalibration and subclinical atherosclerosis imaging, is also discussed.

CONCLUSION

This review highlights the need to develop large, representative, prospectively followed databases of South Asians providing information on various CVD risk factors and their contribution to incident CVD. Such databases will not only allow the development of validated CVD risk scores for South Asians but will also enable application of machine-learning approaches to provide personalized solutions to CVD risk assessment and management in these populations.

The South Asian Paradox

For several decades we have studied health outcomes in identified Asian American (ASAM) ethnic groups, comparing ASAM subgroups to whites and to each other. The most striking disparities we found involved South Asians (SAs). The SA individuals had higher coronary artery disease (CAD) risk and lower cancer risk than whites or any other ASAM group. The SA individuals also did not share the lower venous thromboembolism risk of all other ASAM groups. The relatively low prevalence of CAD risk traits in SAs with high CAD incidence defines a paradox. Exploration of these data might help the search for therapeutic and preventive medical benefits.

The Upcoming Epidemic of Heart Failure in South Asia

Currently, South Asia accounts for a quarter of the world population, yet it already claims ≈60% of the global burden of heart disease. Besides the epidemics of type 2 diabetes mellitus and coronary heart disease already faced by South Asian countries, recent studies suggest that South Asians may also be at an increased risk of heart failure (HF), and that it presents at earlier ages than in most other racial/ethnic groups. Although a frequently underrecognized threat, an eventual HF epidemic in the densely populated South Asian nations could have dramatic health, social and economic consequences, and urgent interventions are needed to flatten the curve of HF in South Asia. In this review, we discuss recent studies portraying these trends, and describe the mechanisms that may explain an increased risk of premature HF in South Asians compared with other groups, with a special focus on highly relevant features in South Asian populations including premature coronary heart disease, early type 2 diabetes mellitus, ubiquitous abdominal obesity, exposure to the world's highest levels of air pollution, highly prevalent pretransition forms of HF such as rheumatic heart disease, and underdevelopment of healthcare systems. Other rising lifestyle-related risk factors such as use of tobacco products, hypertension, and general obesity are also discussed. We evaluate the prognosis of HF in South Asian countries and the implications of an anticipated HF epidemic. Finally, we discuss proposed interventions aimed at curbing these adverse trends, management approaches that can improve the prognosis of prevalent HF in South Asian countries, and research gaps in this important field.

Incidence and Progression of Coronary Artery Calcium in South Asians Compared With 4 Race/Ethnic Groups

Background

South Asians have a relatively high prevalence of coronary artery calcium (CAC) compared with other race/ethnic groups. We determined CAC incidence and progression among South Asians, and compared them with 4 race/ethnic groups.

Methods and Results

Data from the MASALA (Mediators of Atherosclerosis in South Asians Living in America) study were used to calculate CAC incidence and progression rates and any CAC change. Data from the MESA (Multi‐Ethnic Study of Atherosclerosis) were used to compare the CAC incidence and progression rates. A total of 698 South Asians had repeat CAC measurements after 4.8±0.8 years. Among those with no CAC at baseline, the age‐adjusted CAC incidence was 8.8% (95% CI, 6.8–10.8%) in men and 3.6% (2.5–4.8%) in women. The median annual CAC progression was 26 (interquartile range, 11–62) for men and 13 (interquartile range, 4–34) for women. Compared with MESA, age‐adjusted CAC incidence was similar in South Asian men compared with white, black, and Latino men, but significantly higher than Chinese men (11.1% versus 5.7%, P=0.008). After adjusting for age, diabetes mellitus, hypertension, and statin medication use, Chinese, black, and Latino men had significantly less CAC change compared with South Asian men, but there were no differences between South Asian and white men. There was no difference in CAC incidence or progression between South Asian women and women in MESA.

Conclusions

South Asian men had greater CAC change than Chinese, black, and Latino men but similar change to that of whites after adjusting for traditional risk factors.

Lipids in South Asians: Epidemiology and Management

Purpose of Review

This review focuses on lipoprotein abnormalities in South Asians (SA) and addresses risk stratification and management strategies to lower atherosclerotic cardiovascular disease (ASCVD) in this high-risk population.

Recent Findings

South Asians (SAs) are the fastest growing ethnic group in the United States (U.S) and have an increased risk of premature coronary artery disease (CAD). While the etiology may be multifactorial, lipoprotein abnormalities play a key role. SAs have lower low-density lipoprotein cholesterol (LDL-C) compared with Whites and at any given LDL-C level, SA ethnicity poses a higher risk of myocardial infarction (MI) and coronary artery disease (CAD) compared with other non-Asian groups. SAs have lower high-density lipoprotein cholesterol (HDL-C) with smaller particle sizes of HDL-C compared with Whites. SAs also have higher triglycerides than Whites which is strongly related to the high prevalence of metabolic syndrome in SAs. Lipoprotein a (Lp(a)) levels are also higher in SAs compared with many other ethnic groups. This unique lipoprotein profile plays a vital role in the elevated ASCVD risk in SAs. Studies evaluating dietary patterns of SAs in the U.S show high consumption of carbohydrates and saturated fats.

Summary

SAs have a high-risk lipoprotein profile compared with other ethnicities. Lipid abnormalities play a central role in the pathogenesis of CAD in SAs. More studies are needed to understand the true impact of the various lipoproteins and their contribution to increasing ASCVD in SAs. Aggressive lowering of LDL-C in high-risk groups using medications, such as statins, and lifestyle modification including dietary changes is essential in overall CAD risk reduction.

Epidemiology, risk factors, and opportunities for prevention of cardiovascular disease in individuals of South Asian ethnicity living in Europe

South Asian (SA) individuals represent a large, growing population in a number of European countries. These individuals, particularly first-generation SA immigrants, are at higher risk of developing type 2 diabetes, atherogenic dyslipidaemia, and coronary heart disease than most other racial/ethnic groups living in Europe. SAs also have an increased risk of stroke compared to European-born individuals. Despite a large body of conclusive evidence, SA-specific cardiovascular health promotion and preventive interventions are currently scarce in most European countries, as well as at the European Union level. In this narrative review, we aim to increase awareness among clinicians and healthcare authorities of the public health importance of cardiovascular disease among SAs living in Europe, as well as the need for tailored interventions targeting this group - particularly, in countries where SA immigration is a recent phenomenon. To this purpose, we review key studies on the epidemiology and risk factors of cardiovascular disease in SAs living in the United Kingdom, Italy, Spain, Denmark, Norway, Sweden, and other European countries. Building on these, we discuss potential opportunities for multi-level, targeted, tailored cardiovascular prevention strategies. Because lifestyle interventions often face important cultural barriers in SAs, particularly for first-generation immigrants; we also discuss features that may help maximise the effectiveness of those interventions. Finally, we evaluate knowledge gaps, currently available risk stratification tools such as QRISK-3, and future directions in this important field.

Lipoprotein(a): An underrecognized genetic risk factor for malignant coronary artery disease in young Indians

Malignant coronary artery disease (CAD) refers to a severe and extensive atherosclerotic process involving multiple coronary arteries in young individuals (aged <45 years in men and <50 years in women) with a low or no burden of established risk factors. Indians, in general, develop acute myocardial infarction (AMI) about 10 years earlier; AMI rates are threefold to fivefold higher in young Indians than in other populations. Although established CAD risk factors have a predictive value, they do not fully account for the excessive burden of CAD in young Indians. Lipoprotein(a) (Lp(a)) is increasingly recognized as the strongest known genetic risk factor for premature CAD, with high levels observed in Indians with malignant CAD. High Lp(a) levels confer a twofold to threefold risk of CAD-a risk similar to that of established risk factors, including diabetes. South Asians have the second highest Lp(a) levels and the highest risk of AMI from the elevated levels, more than double the risk observed in people of European descent. Approximately 25% of Indians and other South Asians have elevated Lp(a) levels (≥50 mg/dl), rendering Lp(a) a risk factor of great importance, similar to or surpassing diabetes. Lp(a) measurement is ready for clinical use and should be an essential part of all CAD research in Indians.

Racial Disparities in the Cardiac Computed Tomography Assessment of Coronary Artery Disease: Does Gender Matter

Coronary heart disease (CHD) represents a significant healthcare burden in terms of hospital resources, morbidity, and mortality. Primary prevention and early detection of risk factors for the development of CHD are pivotal to successful intervention programs and prognostication. Yet, there remains a paucity of evidence regarding differences in the assessment of these risk factors and the tools of assessment among different ethnicities. We conducted a narrative review to assess the utility of cardiac computed tomography, particularly coronary artery calcification (CAC), in different ethnicities. We also looked to see whether age, sex, comorbidities, and genetic background have peculiar influences on CAC. In this review, we highlight some of the pivotal studies regarding the question of CAC in relation to the development of CHD among different ethnicities. We identify several key trends in the literature showing that although African Americans have high rates of CHD, their risk of CAC may be relatively lower compared with other ethnicities. Similarly, South Asian patients may be at a high risk for adverse cardiac events due to elevated CAC. We also note that several studies are limited by small sample size and were based on 1 large cohort study. Future studies should include a large international prospective cohort to truly evaluate the effects of ethnicity on CAC and CHD risk. To appropriately apply CAC in the clinical practice, the variations in its scoring based on a subject's age, sex, comorbidity, and ethnicity should be addressed and interpreted beforehand.

Discordance between 10-year cardiovascular risk estimates using the ACC/AHA 2013 estimator and coronary artery calcium in individuals from 5 racial/ethnic groups: Comparing MASALA and MESA

BACKGROUND AND AIMS

South Asian (SA) individuals are thought to represent a group that is at high-risk for atherosclerotic cardiovascular disease (ASCVD). However, the performance of the Pooled Cohort Equations (PCE) remains uncertain in SAs living in the US. We aimed to study the interplay between predicted 10-year ASCVD risk and coronary artery calcium (CAC) in SAs compared to other racial/ethnic groups.

METHODS

We studied 536 SAs from the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study, and 2073 Non-Hispanic Whites (NHWs), 1514 African Americans (AAs), 1254 Hispanics, and 671 Chinese Americans (CAs) from the Multi-Ethnic Study of Atherosclerosis (MESA) who were not currently on statins. We used logistic regression models to assess the association between race/ethnicity and CAC within each ASCVD risk stratum.

RESULTS

SAs at low and at intermediate estimated ASCVD risk were more likely to have CAC = 0 compared to NHWs, while SAs at high risk had a similar CAC burden to NHWs. For example, intermediate-risk SAs had a 73% higher odds of CAC = 0 compared to NHWs (95% 1.00-2.99), while high-risk SAs were equally likely to have CAC = 0 (OR 0.95, 95% CI 0.65-1.38) and CAC >100 (OR 0.86, 95% CI 0.61-1.22).

CONCLUSIONS

Our results suggest that the extent of ASCVD risk overestimation using the PCEs may be even greater among SAs considered at low and intermediate risk than among NHWs. Studies with incident ASCVD events are required to validate and/or recalibrate current ASCVD risk prediction tools in this group.

Atherosclerotic Cardiovascular Disease in South Asians in the United States: Epidemiology, Risk Factors, and Treatments: A Scientific Statement From the American Heart Association

South Asians (from Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, and Sri Lanka) make up one quarter of the world's population and are one of the fastest-growing ethnic groups in the United States. Although native South Asians share genetic and cultural risk factors with South Asians abroad, South Asians in the United States can differ in socioeconomic status, education, healthcare behaviors, attitudes, and health insurance, which can affect their risk and the treatment and outcomes of atherosclerotic cardiovascular disease (ASCVD). South Asians have higher proportional mortality rates from ASCVD compared with other Asian groups and non-Hispanic whites, in contrast to the finding that Asian Americans (Asian Indian, Chinese, Filipino, Japanese, Korean, and Vietnamese) aggregated as a group are at lower risk of ASCVD, largely because of the lower risk observed in East Asian populations. Literature relevant to South Asian populations regarding demographics and risk factors, health behaviors, and interventions, including physical activity, diet, medications, and community strategies, is summarized. The evidence to date is that the biology of ASCVD is complex but is no different in South Asians than in any other racial/ethnic group. A majority of the risk in South Asians can be explained by the increased prevalence of known risk factors, especially those related to insulin resistance, and no unique risk factors in this population have been found. This scientific statement focuses on how ASCVD risk factors affect the South Asian population in order to make recommendations for clinical strategies to reduce disease and for directions for future research to reduce ASCVD in this population.

Recent Advances in the Molecular Genetics of Familial Hypertrophic Cardiomyopathy in South Asian Descendants

The South Asian population, numbered at 1.8 billion, is estimated to comprise around 20% of the global population and 1% of the American population, and has one of the highest rates of cardiovascular disease. While South Asians show increased classical risk factors for developing heart failure, the role of population-specific genetic risk factors has not yet been examined for this group. Hypertrophic cardiomyopathy (HCM) is one of the major cardiac genetic disorders among South Asians, leading to contractile dysfunction, heart failure, and sudden cardiac death. This disease displays autosomal dominant inheritance, and it is associated with a large number of variants in both sarcomeric and non-sarcomeric proteins. The South Asians, a population with large ethnic diversity, potentially carries region-specific polymorphisms. There is high variability in disease penetrance and phenotypic expression of variants associated with HCM. Thus, extensive studies are required to decipher pathogenicity and the physiological mechanisms of these variants, as well as the contribution of modifier genes and environmental factors to disease phenotypes. Conducting genotype-phenotype correlation studies will lead to improved understanding of HCM and, consequently, improved treatment options for this high-risk population. The objective of this review is to report the history of cardiovascular disease and HCM in South Asians, present previously published pathogenic variants, and introduce current efforts to study HCM using induced pluripotent stem cell-derived cardiomyocytes, next-generation sequencing, and gene editing technologies. The authors ultimately hope that this review will stimulate further research, drive novel discoveries, and contribute to the development of personalized medicine with the aim of expanding therapeutic strategies for HCM.

Risk of cancer in Asian Americans: a Kaiser Permanente cohort study

PURPOSE

To supplement published cohort data about incident cancer in Asian Americans (Asians) including risk of specific Asian ethnic groups.

METHODS

A cohort study in 124,193 persons (13,344 Asians) with baseline examination data in 1978-1985 used Cox proportional hazards models with seven covariates to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs).

RESULTS

Through 2012 cancer was diagnosed in 18,687 persons including 1,522 Asians. Compared to Whites, the HR (CIs) for any cancer in Asians was 0.8 (0.7-0.9, p < 0.001). Lower Asian risk was stronger for men (HR = 0.7, p < 0.001) than for women (HR = 0.9, p = 0.003). Lower Asian vs. White risks with p < 0.05 were found for cancers of the upper airway digestive area, hematologic malignancies, melanoma, and cancers of the prostate, bladder, and brain. Melanoma contributed substantially to lower Asian risk, especially in women. HRs for specific Asian groups versus Whites follow: Chinese = 0.9 (p < 0.001), Japanese = 0.9 (p = 0.01), Filipinos = 0.8 (p < 0.001), South Asians = 0.5 (p < 0.001), and Other Asians = 0.7 (p = 0.006). Both South Asian men and women had lower risk than Whites, and South Asians had lower risk than any other racial/ethnic group.

CONCLUSIONS

Asians had lower cancer risk than Whites, due to lower risk of several cancer types. Each Asian ethnic group had lower risk than Whites with South Asians at the lowest risk.

Less favorable body composition and adipokines in South Asians compared with other US ethnic groups: results from the MASALA and MESA studies

Background

Small studies have shown that South Asians (SAs) have more total body, subcutaneous, visceral and hepatic fat and abnormal adipokine levels compared to Whites. However, comprehensive studies of body composition and adipokines in SAs compared to other ethnic groups are lacking.

Methods

Using harmonized data, we performed a cross-sectional analysis of two community-based cohorts: Mediators of Atherosclerosis of South Asians Living in America (MASALA, n=906) and Multi-Ethnic Study of Atherosclerosis (MESA which included 2,622 Whites; 803 Chinese Americans; 1,893 African Americans; and 1,496 Latinos). General linear models were developed to assess ethnic differences in ectopic fat (visceral, intermuscular, and pericardial fat; and hepatic attenuation), lean muscle mass, and adipokines (adiponectin and resistin). Models were adjusted for age, sex, site, alcohol use, smoking, exercise, education, household income and BMI. Ectopic fat models were additionally adjusted for hypertension, diabetes, HDL, and triglycerides. Adipokine models were adjusted for subcutaneous, visceral, intermuscular, and pericardial fat; and hepatic attenuation.

Results

Compared to all ethnic groups in MESA (Whites, Chinese Americans, African Americans, and Latinos), SAs had greater intermuscular fat (pairwise comparisons to each MESA group, p < 0.01), lower hepatic attenuation (p < 0.001), and less lean mass (p < 0.001). SAs had greater visceral fat compared to Chinese Americans, African Americans and Latinos (p < 0.05) and greater pericardial fat compared to African Americans (p < 0.001). SAs had lower adiponectin levels compared to other ethnic groups (p < 0.01; except Chinese Americans) and higher resistin levels than all groups (p < 0.001), even after adjusting for differences in body composition.

Conclusion

There are significant ethnic differences in ectopic fat, lean mass, and adipokines. A less favorable body composition and adipokine profile in South Asians may partially explain the increased predisposition to cardiometabolic disease. The mechanisms that underlie these differences warrant further investigation.

Comparing coronary artery calcium among U.S. South Asians with four racial/ethnic groups: the MASALA and MESA studies

OBJECTIVES

South Asians (individuals from India, Pakistan, Bangladesh, Nepal, and Sri Lanka) have high rates of cardiovascular disease which cannot be explained by traditional risk factors. Few studies have examined coronary artery calcium (CAC) in South Asians.

METHODS

We created a community-based cohort of South Asians in the United States and compared the prevalence and distribution of CAC to four racial/ethnic groups in the Multi-Ethnic Study of Atherosclerosis (MESA). We compared 803 asymptomatic South Asians free of cardiovascular disease to the four MESA racial/ethnic groups (2622 Whites, 1893 African Americans, 1496 Latinos and 803 Chinese Americans).

RESULTS

The age-adjusted prevalence of any CAC was similar between White and South Asian men, but was lower in South Asian women compared to White women. After adjusting for all covariates associated with CAC, South Asian men were similar to White men and had higher CAC scores compared to African Americans, Latinos and Chinese Americans. In fully adjusted models, CAC scores were similar for South Asian women compared to all women enrolled in MESA. However, South Asian women ≥70 years had a higher prevalence of any CAC than most other racial/ethnic groups.

CONCLUSIONS

South Asian men have similarly high CAC burden as White men, but higher CAC than other racial/ethnic groups. South Asian women appear to have similar CAC burden compared to other women, but have somewhat higher CAC burden in older age. The high burden of subclinical coronary atherosclerosis in South Asians may partly explain higher rates of cardiovascular disease in South Asians.