The Risk of Atherosclerotic Cardiovascular Disease in South Asians

By Rukan Saif, Copy Editor


Graphic by Alex Jeon

Over the past half-century, the number of South Asians in America has skyrocketed to over 5.4 million. These people, who have roots in Bangladesh, Bhutan, India, the Maldives, Nepal, Pakistan, or Sri Lanka, are typically defined by their rich culture and indomitable work ethic. Their stories of perseverance in the face of a xenophobic America are remarkable, and I should know — my parents are one account among millions.


However, South Asians are also known for something far more life-threatening and, unfortunately, prevalent: atherosclerotic cardiovascular disease, or ASCVD. ASCVD is caused by plaque buildup in arterial walls and refers to coronary heart disease, cerebrovascular disease, peripheral artery disease, or aortic atherosclerotic disease. According to the American Heart Association, South Asians have a higher proportional mortality rate from ischemic heart disease than other Asian ethnic groups and non-Hispanic whites. And in the New York Times article “Why Do South Asians Have Such High Rates of Heart Disease?,” Stanford South Asian Translational Heart Initiative (SSATHI) cardiologist Dr. Abha Khandelwal acknowledges the grim reality that South Asians “all have someone in [their] first-degree circle that has either died suddenly or had premature cardiovascular disease.”


What makes this issue more complex, though, is the combination of biological and nonbiological risk factors it propounds. For example, South Asians have twice the risk of developing Type 2 diabetes, which is a recognized independent risk factor and predictor of ASCVD. This group also experiences a prevalence of impaired glucose tolerance. In a study examining altered insulin levels in the children of South Asian immigrants, it was observed that South Asian young adults had lower IGFBP-1, a protein important in cell migration and metabolism. Lower levels of this protein are generally associated with hypertension and vascular disease. Additionally, South Asians bear the burden of intergenerational health effects like high blood pressure, less lean muscle mass, and a tendency to store fat in the liver and abdomen, which can catalyze the onset of heart disease. Yet, as mentioned above, it would be precipitous to blame only scientific mechanisms when the sociopolitical climate has proven to be a veritable adversary in achieving universal health equity.


For several immigrants, acculturation, which is the adoption of customs and principles of one cultural group by another, seems like a strategy essential to assimilation, and South Asians are not exempt. Acculturation can manifest itself through slipping out of one’s mother tongue or even drastic diet changes. According to the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study, South Asian immigrants commonly adopt dietary habits of Western countries, thereby substituting familiar foods with an alien dietary pattern. Invariably connected is the observation that “a longer duration of residence in the United States has been associated with higher levels of coronary artery calcification (CAC).” This integration of Western dietary habits can compound the potentially deleterious effects of the South Asian diet. Since several South Asians are vegetarian for religious or cultural reasons, their diet is saturated with carbohydrates and fats, an abundance of which can exacerbate cardiovascular conditions. Additionally, cultural differences play into ASCVD risk. Dr. Namratha Kandula, a Northwestern University researcher, points out “not regularly exercising” as being one. This empirical observation is supported by a study conducted by the University of Glasgow, which found that “lower cardiorespiratory fitness [is] associated with insulin resistance.” From this, there is conclusive evidence that all of these risk factors — biological and non biological — work in tandem with each other. When someone of South Asian descent incorporates fries, soda, and pizza into daily eating patterns, their already high carbohydrate and fat levels shoot up. This, compounded with the lack of emphasis on physical activity, puts that person on an incontrovertible path to weaker heart health.


Because of the striking risk of ASCVD, early interventions must be taken through risk assessment tools. The MASALA study concluded that 9.7% of participants reported gestational diabetes mellitus (GDM), which is defined as glucose intolerance with onset or first recognition during pregnancy, and that women with GDM are 3.2 times more likely to develop Type 2 diabetes than those without GDM, showing that, regardless of age, many are at risk for ASCVD. To collate the accurate statistics, the medical field should employ increased use of computed tomography angiography (CTA) and carotid intimal-medial thickness (CIMT) estimation to predict cardiovascular events. CTA, which uses a special dye injection to diagnose aneurysms and blockages, has been able to “demonstrate variable ASCVD distribution patterns, higher amounts of stenosis, and smaller luminal diameters in South Asians,” according to the American Heart Association. Additionally, the United Kingdom has been using QRISK2 and ETHRISK, which are two risk assessment tools. These calculators take into account determinants like smoking, body mass index (BMI), cholesterol/HDL ratio, systolic blood pressure, and ethnic background to estimate ASCVD risk. While QRISK2 and ETHRISK are being universally used, the United States should not only adopt their usage but also develop and validate them to ensure a safer, individualized path to heart health.


Ultimately, it is common knowledge that South Asians are known for their cornucopia of indulgent foods: amosa, jalebi, and biryani. As a member of this community, I’m not asking for us to give up family favorites like potato-filled parathas and creamy curries. I am imploring for us to reflect on our dietary and exercising habits to give us a better chance at heart health and to establish our global legacy through our rich histories and cultures — not through ASCVD.


References:

https://www.ahajournals.org/doi/pdf/10.1161/CIR.0000000000000580#:~:text=South%20Asians%20have%20higher%20proportional,largely%20because%20of%20the%20lower

https://www.acc.org/latest-in-cardiology/articles/2019/05/07/12/42/cover-story-south-asians-and-cardiovascular-disease-the-hidden-threat

https://www.jwatch.org/na46943/2018/06/20/addressing-ascvd-risks-south-asians-us-scientific

https://www.masalastudy.org/blog

https://www.genecards.org/cgi-bin/carddisp.pl?gene=IGFBP1

https://www.nytimes.com/2019/02/12/well/live/why-do-south-asians-have-such-high-rates-of-heart-disease.html

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