Getting to the Heart of it:
South Asians’ predisposition to cardiovascular disease

Chronic metabolic and cardiovascular diseases (CVD) have popularly been called “diseases of affluence” because of their association with urban lifestyles through factors such as decreased physical activity, carbohydrate-rich diets and other risk determinants like smoking and high blood pressure1. It seems puzzling then that these diseases disproportionately affect low- and middle-income countries. Numerous research studies have shown that biological and genetic predispositions also play a role, especially in certain ethnic populations such as South Asians, who face a higher risk of CVD and metabolic diseases compared to Caucasians2–5. Though hypertension, diabetes, and central adiposity explain some of this risk, they do not justify the extent of these risk factors in these ethnicities.

To truly understand why these diseases impact South Asians differently, we need to take a closer look at the intersection of three important contributors: 1) the history of these communities and their relationship with colonial powers, 2) changing trade dynamics, and 3) the effects of improved public health practices, cultural shifts and technology-driven changes in nutritional practices. Over the course of four articles, we will delve into the historical, economic, cultural and biological factors that lead to a heightened risk of metabolic and cardiovascular disease in South Asian populations. In the first article of this series, we will introduce the topic in the context of each of the aforementioned factors, and provide a basis upon which we can continue to explore them in greater depth.

The term “South Asia” now broadly describes the region comprising the countries Bangladesh, India, Pakistan, Bhutan, Sri Lanka,  Nepal, and the Maldives. This label did not exist five centuries ago when Europeans began trading with the region6, and seems to have arisen as a result of colonial expansion rather than geographical proximity (see figure)7. In fact, one of the seminal textbooks pertaining to the region, Modern South Asia: History, Culture, Political Economy, contains only cursory mentions of the latter four countries with its primary focus being on India8. Most social science and scientific research on “South Asian populations” tends also to be India-centric. This conflation can cause concerning inaccuracies. For instance, there are significant known differences in CVD risk between Bangladeshis and Pakistanis, and Indians5. Evidently, colonial expansion still impacts our present-day understanding of how risk factors contribute to disease. Our understanding of the biological and genetic bases of metabolic and CVD must hence be informed by more granular histories and economic policies, as opposed to sweeping generalizations about South Asians as a whole.

One of the challenges in directly tracing the increase in CVD risk to pre-colonial and colonial history is our inability to build computational or statistical models that can attempt to glean causal relationships from historical health data. An intersectional approach to understanding the increased risk thus involves logic-based reconciliation of oral histories, and travellers’ and administrative accounts with more recently available health and genomic data. Oral histories can provide useful insights into health and nutrition over significant historical durations through their accounts of foodways, since food is inextricably linked with culture. In the 1980s and 90s, an extensive body of literature emerged which examined how British colonialism impacted food processes and governance surrounding food, including the cruel

Figure. A map portraying the expansion of the British Indian Empire (Source: Atlas of World History). The colonial era in India is believed to have started in the early 16th century when Portuguese traders established the first European trading center in Quillon (now Kollam in the state of Kerala located in the South of India). While the Dutch established trading posts across coastal India and held a monopoly on spice trade for a considerable part of the 17th century, the British East India Company’s monopoly on textile trade being more profitable allowed them to overtake the Dutch9. This brief account has been oversimplified for succinctness.