Neglected Tropical Diseases as Hidden Causes of Cardiovascular Disease

An important component of the burden of cardiovascular disease in low- and middle-income countries may be attributed to the neglected tropical diseases. There is a growing awareness of the importance of chronic non-communicable diseases (CNCDs) in the world's low- and middle-income countries (LMICs). Beginning in the 1990s, Murray and Lopez predicted a doubling of death rates due to cardiovascular disease in developing countries by 2020 [1], while a substantial rise was also predicted by Leeder et al. [2]. Based on World Health Organization (WHO) predictions, 75% of the burden of cardiovascular disease is found in LMICs [3]. Alarming increases have also been noted for other CNCDs in LMICs including cancer, chronic respiratory diseases, and diabetes [4]. In September 2011, a report by the World Economic Forum and the Harvard School of Public Health estimated the global economic burden of CNCDs over the next two decades to be US$47 trillion [5]. During this same month, the United Nations General Assembly held a high-level meeting to discuss prevention and control of CNCDs, including cardiovascular diseases, in LMICs [6]. These initiatives have focused on preventable risk factors attributable to lifestyle changes such as tobacco and alcohol use, prolonged unhealthy nutrition, and physical inactivity, which currently account for a high proportion of cardiovascular deaths in North America and Europe [4]–[6]. While there is no question that obesity, tobacco, and alcohol represent major underlying conditions responsible for the rise of cardiovascular and other CNCDs in LMICs, they do not provide a complete picture. In March of 2011, Partners in Health and Harvard Medical School sponsored a conference entitled “The Long Tail of Global Health Equity: Tackling the Endemic Non-Communicable Diseases of the Bottom Billion” to examine in more detail some of the neglected causes of CNCDs, particularly those that are unique to the world's poorest people in LMICs. The conference highlighted important risk factors apart from the lifestyle changes linked to CNCDs in high-income countries [7]. Specifically with respect to neglected populations, an important component of cardiovascular disease may be attributable to neglected tropical diseases (NTDs) and other infections of poverty. For example, the Heart of Soweto Study from South Africa identified rheumatic heart disease, tuberculosis, and HIV as significant contributors to heart disease and more common than coronary artery disease. Even in the urbanized region of Soweto where there is a high prevalence of vascular risk factors, non-ischemic etiologies are still the dominant cause of heart failure [8], [9]. On a global level, the contribution of infections of poverty to heart disease can be seen in analyzing the Global Burden of Disease estimates from the WHO. According to this data, approximately 8.8% of the disability-adjusted life years (DALYs) of LMICs may be attributable to cardiovascular disease [3]. Almost one-half of this cardiovascular disease burden is attributable to ischemic heart disease, more than one-third to cerebrovascular disease, and the remainder to hypertensive and inflammatory causes, as well as rheumatic heart disease (Figure 1). A detailed analysis of these conditions suggests that NTDs and other neglected infections may account for a significant component of each of these cardiovascular disease categories (Table 1). Figure 1 Distribution of DALYs attributed to cardiovascular disease among low- and middle-income countries (LMICs). Table 1 Estimated Prevalence of Cardiovascular Disease Caused by Neglected Tropical Diseases and Neglected Infections of Poverty.