The South Asian Paradox: A Global Health Mystery

Epidemiologist Mohammed Ali has been grappling with the issue of heart health for much of his life. He recalls his uncles in Pakistan experiencing heart attacks at a young age, with one tragically passing away at 39. This realization led him to discover that early heart disease is alarmingly common among individuals with South Asian ancestry. This vast region, encompassing India, Pakistan, Bangladesh, Sri Lanka, and the Maldives, accounts for approximately one-quarter of the global population, yet shoulders a disproportionate burden of heart disease, with up to 60% of cases originating from this region.

Despite their diverse geographic distribution and varying lifestyles, South Asians across the globe share an elevated risk for cardiovascular disease, a phenomenon known as the South Asian paradox. This paradox is perplexing because many South Asians have heart disease even without traditional risk factors like smoking or high body mass index. This raises questions about the underlying causes, prompting a deeper exploration into the complexities of this health disparity.

The Search for Answers: Genetics and Beyond

The South Asian paradox has puzzled researchers and clinicians for decades. Genetics was initially considered a likely culprit, but a dearth of data on South Asian populations has hindered research progress. Notably, this group represents less than 2% of genomics study participants and less than 0.5% of participants in cardiovascular disease clinical trials.

However, this situation is starting to change. In India, researchers have successfully sequenced 10,000 genomes, paving the way for a better understanding of genetic variations within the population. The US National Heart, Lung, and Blood Institute has also launched a program dedicated to studying 10,000 individuals with East Asian, South Asian, Southeast Asian ancestry, and those identifying as Native Hawaiian or Pacific Islander. Moreover, a research program called OurHealth, launched in October 2023, is focusing on quantifying risk factors within the South Asian community, particularly genetic risks. These efforts provide a promising avenue for uncovering the genetic basis of heart disease susceptibility in South Asian populations.

The Social Determinants of Health: A Crucial Lens

While genomics research holds promise for understanding the genetic factors contributing to heart disease in South Asians, some experts caution against focusing solely on genetics. They argue that such an approach could oversimplify a complex issue and potentially reinforce harmful racial stereotypes in medicine. Instead, they emphasize the importance of considering social and environmental factors, often referred to as social determinants of health.

The high rates of cardiovascular disease among South Asians are not merely a recent phenomenon. Studies dating back to the 1960s observed elevated rates of diabetes and cardiovascular disease among South Asian immigrants in the US, UK, Singapore, and other countries. This trend expanded within India itself after the economic liberalization of 1991, likely due to the increased availability of calorie-rich foods and reduced physical activity associated with industrialization.

The Need for a Holistic Approach

The AHA's risk calculator acknowledges that genetic factors are not the sole contributors to the elevated risk of cardiovascular disease in South Asians. It uses racial heritage as a proxy for non-genetic factors that influence disease risk, beginning even before birth. This includes the higher prevalence of gestational diabetes among South Asian women, which can predispose their offspring to the condition. Furthermore, South Asian children tend to engage in less physical activity and consume carbohydrate-heavy diets, contributing to increased risk. The accelerated progression from prediabetic to diabetic states in South Asians compared to other ethnicities poses a significant challenge for early detection and treatment.

Racism also plays a critical role in shaping health disparities. The intergenerational trauma stemming from colonialism, the migration experience, and ongoing racism in new countries can have lasting biological impacts on South Asian individuals. These social and environmental factors significantly influence cardiovascular health, yet medicine is struggling to quantify and address them adequately.

Bridging the Gap: Incorporating Social Science

The focus on genomics research is commendable, but experts urge for a balanced approach that also prioritizes social science research. Understanding the interplay between social determinants and biological factors is crucial for developing effective and scalable interventions. This includes addressing issues like diet, physical activity, stress management, and access to healthcare.

Moving Forward: A Call for Action

The South Asian paradox calls for a multi-pronged approach that encompasses both genetics and social determinants of health. By expanding genomics research while simultaneously investing in social science-based interventions, we can work towards achieving better heart health outcomes for South Asian populations. This requires a collaborative effort involving researchers, clinicians, policymakers, and community members, ensuring that research and interventions are culturally sensitive and meet the unique needs of this diverse group. Only through a holistic understanding of the factors contributing to the South Asian paradox can we truly make a difference in combating cardiovascular disease and promoting health equity for all.

The Future of South Asian Heart Health: A Call for Action

The South Asian paradox is a complex and multifaceted issue that requires a comprehensive approach. While genetics plays a role, we must acknowledge the significant impact of social determinants of health, such as racism, socioeconomic status, and access to healthcare. Investing in social science research and interventions alongside genomics studies will be crucial for achieving lasting positive change. By bridging the gap between biological and social factors, we can create a future where cardiovascular disease is effectively prevented and managed, ensuring equitable health outcomes for all South Asians.