South Asian Cardiovascular Disease & Cancer Risk: Genetics & Pathophysiology

Trends in cigarette smoking and the risk of incident cardiovascular disease among Asian American, Pacific Islander, and multiracial populations

Background

Cardiovascular disease (CVD) is the leading cause of death in the United States, and rates of CVD incidence vary widely by race and ethnicity. Cigarette smoking is associated with increased risk of CVD. The purpose of the study was: 1) to examine smoking prevalence over time across Asian and Pacific Islander (API) and multi-race API subgroups; 2) to determine whether the CVD risk associated with smoking differed among these subgroups.

Methods

We identified patients belonging to 7 single race/ethnicity groups, 4 multi-race/ethnicity groups, and a non-Hispanic White (NHW) comparison group at two large health systems in Hawaii and California. We estimated annual smoking prevalence from 2011 through 2018 by group and gender. We examined incidence of CVD events by smoking status and race/ethnicity, and computed hazard ratios for CVD events by age, gender, race/ethnicity, census block median household income, census block college degree, and study site using Cox regression.

Results

Of the 12 groups studied, the Asian Indian and Chinese American groups had the lowest smoking prevalence, and the Asian + Pacific Islander multiracial group had the highest smoking prevalence. The prevalence of smoking decreased from 2011 to 2018 for all groups. Multi-race/ethnicity groups had higher risk of CVD than the NHW group. There was no significant interaction between race/ethnicity and smoking in models predicting CVD, but the association between race/ethnicity and CVD incidence was attenuated after adjusting for smoking status.

Conclusions

There is considerable heterogeneity in smoking prevalence and the risk of CVD among API subgroups.

Temporal Trends and Burden of Rheumatic Heart Disease in South Asia: A Comprehensive Analysis of Three Decades from Global Burden of Disease Study

Background

The objective of this study is to conduct a temporal analysis of rheumatic heart disease (RHD) disease burden trends over a 30-year period (1991 to 2021), focusing on prevalence, deaths, and disability-adjusted life years (DALYs) in the South Asia (SA).

Methods

In this ecological study, we analyzed data regarding burden of RHD from the Global Burden of Diseases (GBD) study spanning the years 1991 to 2021 for the SA Region. Estimates of the number RHD-related prevalence, deaths, and DALYs along with age-standardized rates (ASR) per 100,000 population and 95% uncertainty intervals (UI) were evaluated.

Results

The overall prevalent cases of RHD in the 2021 were 54785.1 × 103 (43328.4 × 103 to 67605.5 × 103), out of which 14378.8 × 103 (11206.9 × 103 to 18056.9 × 103) were from SA. The ASR of point prevalence showed upward trend between 1991 and 2021, at global level and for SA with an average annual percentage change (AAPC) of 0.40 (0.39 to 0.40) and 0.12 (0.11 to 0.13), respectively. The overall number of RHD-related deaths in the 2021 were 373.3 × 103 (324.1 × 103 to 444.8 × 103), out of which 215 × 103 (176.9 × 103 to 287.8 × 103) were from SA, representing 57.6% of the global deaths. The ASR of deaths also showed downward trend between 1991 and 2021, at global level and for SA with an AAPC of -2.66 (-2.70 to -2.63) and -2.07 (-2.14 to -2.00), respectively. The ASR of DALYs showed downward trend between 1990 and 2019, at global level and for South Asian region with an AAPC of -2.47 (-2.49 to -2.44) and -2.22 (-2.27 to -2.17), respectively.

Conclusion

The rising age-standardized prevalence of RHD remains a global concern, especially in South Asia which contribute to over 50% of global RHD-related deaths. Encouragingly, declining trends in RHD-related deaths and DALYs hint at progress in RHD management and treatment on both a global and regional scale.

Cardiovascular health amongst South Asian populations in British Columbia: A situational and comparative analysis of preventative strategies

This analysis provides an overview of cardiovascular health among South Asian populations in British Columbia (BC), Canada utilizing peer-reviewed literature, alongside data from public health authorities and relevant jurisdictions. The analysis identified risk factors for cardiovascular disease (CVD) amongst South Asians and discussed preventative public health strategies and interventions to mitigate disease burden. The situational analysis discussed the disproportionate increased risk for CVD in South Asians when compared to other ethnicities in BC, highlighting lifestyle choices, genetic predispositions, socio-economic status (SES), and post-migration-related challenges. The analysis identified a disproportionate increase in heart disease in South Asian males and females when compared to White males and females. A review of evidence from peer-reviewed literature identified previously conducted studies and intervention strategies to address CVD and its risk factors. Common themes across multiple studies included addressing physical inactivity and dietary habits as increased cholesterol, obesity, and DM reported as the most common prevalent CVD risk factors in South Asians. The most significantly studied modifiable risk factors in literature for South Asians included diet and physical inactivity. To identify promising public health interventions, a comparative analysis was conducted identifying multiple public health programs from three different jurisdictions: Ontario, New York, and California to better understand successful preventative strategies to decrease risk factors for CVD. A New York based study implemented preventive health programs at employment sites with high prevalence of South Asians, such as Taxi drivers. Successful interventions included culturally relevant diabetes prevention programs, community outreach and health risk assessments in religious centers, health fairs at employment sites, and culturally competent online behavioural modification programs addressing diet and physical activity. Findings from the analysis suggest successful implementation of programs include those from a cultural lens. These include culturally tailored virtual classes, programs with modified risk assessment tools, preventative health community outreach in religious centers, interventions at workplaces with a high number of South Asians, and behavioural modification programs with nutritionists and health coaches.

Turning the Health Equity Lens to Diversity in Asian American Health Profiles

The monolithic misrepresentation of Asian American (AsAm) populations has maintained assumptions that AsAm people are not burdened by health disparities and social and economic inequities. However, the story is more nuanced. We critically review AsAm health research to present knowledge of AsAm health profiles from the past two decades and present findings and opportunities across three topical domains: (a) general descriptive knowledge, (b) factors affecting health care uptake, and (c) effective interventions. Much of the literature emphasized underutilization of health care services; low knowledge and awareness among AsAms about health-related risk factors, prevention, diagnosis, and treatment; inadequate efforts by health systems to improve language access, provider-patient communication, and trust; and the critical roles of community- and faith-based organizations and leaders in health promotion initiatives. Future opportunities for AsAm health research will require adoption of and significant investment in community-engaged research infrastructure to increase representation, funding, and research innovation for AsAm communities.

Generation of induced pluripotent stem cell lines from South Asian ethnicity

South Asians, which represent around 25% of the world's population, have a disproportionately high risk of cardiometabolic disease, two-fold higher risk of myocardial infarction, and 4- to 6-fold higher risk for diabetes compared to Caucasians. We generated two induced pluripotent stem cell (iPSC) lines from healthy South Asian donors and validated the pluripotency and ability of these cell lines to differentiate into three germ layers. These iPSC lines can be applied to generate many cardiovascular cell types such as cardiomyocytes, endothelial cells, and mural cells to investigate different cardiovascular disease mechanisms triggered by environmental risk factors or drugs in vitro.

The Development of a Chest-Pain Protocol for Women Presenting to the Emergency Department

Cardiovascular disease (CVD) is the leading cause of death in women worldwide, and of premature death in women in Canada. Despite improvements in cardiovascular care over the past 15-20 years, acute coronary syndrome (ACS) and CVD mortality continue to increase among women in Canada. Chest pain is a common symptom leading to emergency department visits for both men and women. However, women with ACS experience worse outcomes. compared with those of men, due to misdiagnosis or lack of diagnosis resulting in delayed care and underuse of guideline-directed medical therapies. CVD mortality rates are highest in Indigenous and racialized women and those with a disproportionately high number of adverse social determinants of health. CVD remains underrecognized, underdiagnosed, undertreated, and underresearched in women. Moreover, a lack of awareness of unique symptoms, clinical presentations, and sex-and-gender specific CVD risk factors, by healthcare professionals, leads to outcome disparities. In response to this knowledge gap, in acute recognition and management of chest-pain syndromes in women, the Canadian Women's Heart Health Alliance performed a needs assessment and review of CVD risk factors and ACS pathophysiology, through a sex and gender lens, and then developed a unique chest-pain assessment protocol utilizing modified dynamic programming algorithmic methodology. The resulting algorithmic protocol is presented. The output is intended as a quick reference algorithm that could be posted in emergency departments and other acute-care settings. Next steps include protocol implementation evaluation and impact assessment on CVD outcomes in women.

Were US Asian Indian decedents with atherosclerosis more likely to have concurrent diabetes mellitus? Analysis of national multiple cause of mortality data (2012-2019)

BACKGROUND

Asian Indians (AI) are at high risk for both atherosclerotic diseases (ATH) and diabetes mellitus (DM). We analyze the clustering of these two comorbidities as contributing causes of death in AI versus Non-AI populations in the US.

METHODS

Using Mortality Multiple Cause-of-Death Files (2012-2019) from the National Center for Health Statistics, we included deaths at age ≥ 45 years among US residents where AI versus Non-AI status could be ascertained (n = 55,461 AI; n = 20,090,038 Non-AI) and identsified ATH (ICD10: I20-I25, I63, I70) and DM (ICD10: E10-E14) as contributing causes of death. We calculated the tetrachoric correlation (Rho) between these contributing causes and the difference in the fraction of deaths involving DM in those with versus without ATH.

RESULTS

Among AI decedents, 29.9% of deaths included ATH as a contributing cause, 16.4% included DM as a contributing cause with 8.3% deaths being included in the overlap (Rho = 0.36, SE = 0.007) whereas, among Non-AI, 22.4% of deaths included ATH as a contributing cause, 10.0% included DM as a contributing cause with 4.1% deaths being included in the overlap (Rho = 0.31, SE = 0.001). Thus, DM and ATH as co-occurring causes correlated more strongly in AI versus Non-AI (p < 0.001). Further, this difference in clustering of DM with ATH was highest for younger AI women (age < 60 years) compared to comparable Non-AI women.

CONCLUSIONS

The more frequent co-occurrence of DM and ATH as causes of death among AI compared to Non-AI suggest that the increased burden of these diseases among AI during life has vicious synergistic consequences in terms of mortality. Public health strategies targeted to AI should focus on prevention and clinical treatment of both conditions jointly, in all adults, and especially in women < 60 years.

Comorbidities and ethnic health disparities in the UK biobank

Objective

The goal of this study was to investigate the relationship between comorbidities and ethnic health disparities in a diverse, cosmopolitan population.

Materials and Methods

We used the UK Biobank (UKB), a large progressive cohort study of the UK population. Study participants self-identified with 1 of 5 ethnic groups and participant comorbidities were characterized using the 31 disease categories captured by the Elixhauser Comorbidity Index. Ethnic disparities in comorbidities were quantified as the extent to which disease prevalence within categories varies across ethnic groups and the extent to which pairs of comorbidities co-occur within ethnic groups. Disease-risk factor comorbidity pairs were identified where one comorbidity is known to be a risk factor for a co-occurring comorbidity.

Results

The Asian ethnic group shows the greatest average number of comorbidities, followed by the Black and then White groups. The Chinese group shows the lowest average number of comorbidities. Comorbidity prevalence varies significantly among the ethnic groups for almost all disease categories, with diabetes and hypertension showing the largest differences across groups. Diabetes and hypertension both show ethnic-specific comorbidities that may contribute to the observed disease prevalence disparities.

Discussion

These results underscore the extent to which comorbidities vary among ethnic groups and reveal group-specific disease comorbidities that may underlie ethnic health disparities.

Conclusion

The study of comorbidity distributions across ethnic groups can be used to inform targeted group-specific interventions to reduce ethnic health disparities.

Cardiovascular health through a sex and gender lens in six South Asian countries: Findings from the WHO STEPS surveillance

Background

Sex and gender-based differences in cardiovascular health (CVH) has been explored in the context of high-income countries. However, these relationships have not been examined in low- and middle-income countries. The main aim of this study was to examine how sex and gender-related factors are associated with cardiovascular risk factors of people in South Asian countries.

Methods

We conducted a retrospective analysis of the World Health Organization’s “STEPwise approach to surveillance of risk factors for non-communicable disease” or “STEPS” from six South Asian countries, surveys conducted between 2014-2019. The main outcomes were CVH as measured by a composite measure of STEPS-HEART health index (smoking, physical activity, fruit and vegetable consumption, overweight/obesity, diabetes and hypertension), values ranging from 0 (worst) to 6 (best or ideal) and self-reported occurrence of cardiovascular disease (ie, heart attack and stroke). Multivariate linear and logistic regression models were performed. Multiple imputation with chained equations was performed.

Results

The final analytic sample consisted of 33 106 participants (57.5% females). The mean STEPS-HEART index score in the South Asian population was 3.43 [SD: 0.92]. Female sex (β: 0.05, 95% confidence interval (CI) = 0.01-0.08, P < 0.05) was significantly associated with better CVH compared to males. Being married (β_male = -0.30, 95% CI = -0.37, -0.23 vs β_female = -0.23, 95% CI = -0.29, -0.17; P < 0.001) and having a household size ≥5 (β_male = -0.15, 95% CI = -0.24, -0.06 vs β_female = -0.11, 95% CI = -0.16, -0.04; P < 0.01) were associated with poorer CVH, more so in males. Being married was also associated with high risk of CVD (OR_male = 2.54, 95% CI = 1.68-3.86, P < 0.001 vs OR_female = 1.19, 95% CI = 0.84-1.68, P = 0.31), significant in males.

Conclusions

Among the South Asian population, being female may be advantageous in having an ideal CVH. However, gender-related factors such as marital status and large household size were associated with poorer CVH and greater risk of CVD, regardless of sex.

Coronary plaque and clinical characteristics of South Asian (Indian) patients with acute coronary syndromes: An optical coherence tomography study

BACKGROUND

South Asians, and Indians in particular, are known to have a higher incidence of premature atherosclerosis and acute coronary syndromes (ACS) with worse clinical outcomes, compared to populations with different ethnic backgrounds. However, the underlying pathobiology accounting for these differences has not been fully elucidated.

METHODS

ACS patients who had culprit lesion optical coherence tomography (OCT) imaging were enrolled. Culprit plaque characteristics were evaluated using OCT.

RESULTS

Among 1315 patients, 100 were South Asian, 1009 were East Asian, and 206 were White. South Asian patients were younger (South Asians vs. East Asians vs. Whites: 51.6 ± 13.4 vs. 65.4 ± 11.9 vs. 62.7 ± 11.7; p < 0.001) and more frequently presented with ST-segment elevation myocardial infarction (STEMI) (77.0% vs. 56.4% vs. 35.4%; p < 0.001). On OCT analysis after propensity group matching, plaque erosion was more frequent (57.0% vs. 38.0% vs. 50.0%; p = 0.003), the lipid index was significantly greater (2281.6 [1570.8-3160.6] vs. 1624.3 [940.9-2352.4] vs. 1303.8 [1090.0-1757.7]; p < 0.001), and the prevalence of layered plaque was significantly higher in the South Asian group than in the other two groups (52.0% vs. 30.0% vs. 34.0%; p = 0.003).

CONCLUSIONS

Compared to East Asians and Whites, South Asians with ACS were younger and more frequently presented with STEMI. Plaque erosion was the predominant pathology for ACS in South Asians and their culprit lesions had more features of plaque vulnerability.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov, NCT03479723.

Cancer Mortality Disparities among Asian American and Native Hawaiian/Pacific Islander Populations in California

BACKGROUND

Asian American and Native Hawaiian/Pacific Islanders (AANHPI) are the fastest growing minority in the United States. Cancer is the leading cause of death for AANHPIs, despite relatively lower cancer morbidity and mortality. Their recent demographic growth facilitates a detailed identification of AANHPI populations with higher cancer risk.

METHODS

Age-adjusted, sex-stratified, site-specific cancer mortality rates from California for 2012 to 2017 were computed for AANHPI groups: Chinese, Filipino, South Asian, Vietnamese, Korean, Japanese, Southeast Asian (i.e., Cambodian, Hmong, Laotian, Thai), and Native Hawaiian and Other Pacific Islander (NHOPI). Regression-derived mortality rate ratios (MRR) were used to compare each AANHPI group to non-Hispanic whites (NHW).

RESULTS

AANHPI men and women (total 40,740 deaths) had lower all-sites-combined cancer mortality rates (128.3 and 92.4 per 100,000, respectively) than NHWs (185.3 and 140.6) but higher mortality for nasopharynx, stomach, and liver cancers. Among AANHPIs, both NHOPIs and Southeast Asians had the highest overall rates including for colorectal, lung (men only), and cervical cancers; South Asians had the lowest. NHOPI women had 41% higher overall mortality than NHWs (MRR = 1.41; 95% CI, 1.25-1.58), including for breast (MRR = 1.33; 95% CI, 1.08-1.65) and markedly higher for endometrial cancer (MRR = 3.34; 95% CI, 2.53-4.42).

CONCLUSIONS

AANHPI populations present with considerable heterogeneous cancer mortality patterns. Heightened mortality for infection, obesity, and tobacco-related cancers in Southeast Asians and NHOPI populations highlight the need for differentiated priorities and public health interventions among specific AANHPI populations.

IMPACT

Not all AANHPIs have favorable cancer profiles. It is imperative to expand the focus on the currently understudied populations that bear a disproportionate cancer burden.

Managing cardiovascular disease risk in South Asian kidney transplant recipients

South Asians (SA) are at higher cardiovascular risk than other ethnic groups, and SA kidney transplant recipients (SA KTR) are no exception. SA KTR experience increased major adverse cardiovascular events both early and late post-transplantation. Cardiovascular risk management should therefore begin well before transplantation. SA candidates may require aggressive screening for pre-transplant cardiovascular disease (CVD) due to their ethnicity and comorbidities. Recording SA ethnicity during the pre-transplant evaluation may enable programs to better assess cardiovascular risk, thus allowing for earlier targeted peri- and post-transplant intervention to improve cardiovascular outcomes. Diabetes remains the most prominent post-transplant cardiovascular risk factor in SA KTR. Diabetes also clusters with other metabolic syndrome components including lower high-density lipoprotein cholesterol, higher triglycerides, hypertension, and central obesity in this population. Dyslipidemia, metabolic syndrome, and obesity are all significant CVD risk factors in SA KTR, and contribute to increased insulin resistance. Novel biomarkers such as adiponectin, apolipoprotein B, and lipoprotein (a) may be especially important to study in SA KTR. Focused interventions to improve health behaviors involving diet and exercise may especially benefit SA KTR. However, there are few interventional clinical trials specific to the SA population, and none are specific to SA KTR. In all cases, understanding the nuances of managing SA KTR as a distinct post-transplant group, while still screening for and managing each CVD risk factor individually in all patients may help improve the long-term success of all kidney transplant programs catering to multi-ethnic populations.

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.

The Role of Physical Activity Prescription in Cardiovascular Disease Prevention Amongst South Asian Canadians

Unequivocal evidence suggests an increased prevalence of cardiovascular disease (CVD) amongst South Asian Canadians (SACs) compared to other ethnic cohorts, due to a combination of their unique cardiometabolic profile and environmental factors. This unfavorable CVD profile is characterized by an elevated risk of dyslipidemia, high apolipoprotein B/apolipoprotein A1 ratio, hypertension, glucose intolerance, type 2 diabetes mellitus, as well as increased BMI, body fat percentage, abdominal and visceral adiposity. Despite the overwhelming evidence for the effectiveness of physical activity (PA) in circumventing the onset of CVD and in the reduction of CVD risk factors, SACs are among the most physically inactive cohorts in Canada. This relates to a set of common and unique socio-cultural barriers, such as gender, beliefs and perceptions about illness, immigration, unfavorable PA environments, and their high prevalence of debilitating chronic diseases. Several strategies to improve PA participation rates in this high-risk population have been suggested, and include the implementation of culturally sensitive PA interventions, as well as clinician training in PA prescription through workshops that emphasize knowledge translation into clinical practice. Therefore, the purpose of this mini-review is to highlight and discuss: (1) the burden of heart disease in SACs (2) the cardiovascular benefits of PA for SACs; (3) factors affecting PA participation among SACs and how they can be addressed; (4) the impact of culturally sensitive PA prescription on CVD prevention; (5) barriers to culture-specific PA prescription by clinicians, and strategies to improve its use and impact.