Household Air Pollution and CVD: Identifying Best Directions for Research

Abstract

We face an increasing global burden of cardiovascular disease, principally due to a sharp rise in developing countries experiencing health transitions. While it has long been known that hypertension, cigarette smoking, hypercholesterolemia, and diabetes are important cardiovascular risk factors, it is now increasingly appreciated that environmental factors like fine-particulate air pollution represent a serious public health threat. As noted by Rajagopolan and Brook elsewhere in this issue, household air pollution from use of coal and biomass for cooking and space heating may well have a substantial, and potentially reversible, cardiovascular impact. Rajagopolan and Brook call for a concerted research program to estimate the impact and to develop and test interventions. They correctly note that there is a need to balance the cost of research with the necessity of additional information. Further, they identify five focus areas, including exposure assessment, biological mechanisms, epidemiology, and candidate interventions and their cost-effectiveness. They argue that multidisciplinary teams are best equipped to tackle this complex issue from both scientific and societal perspectives. Research, like many other goods and services, is a scarce resource for which we have to make difficult decisions about expected returns and opportunity costs. There is no question that properly done research offers substantive benefits at reasonable rates of return. Cutler and Kadiyala analyzed the impact of research on cardiovascular health in the United States [1]. They noted the dramatic decline in cardiovascular mortality seen over the last 50 years can be attributed to three major factors: high-technology care, low-technology care, and behavioral change. Quite remarkably these declines have continued as age-adjusted death rates for coronary heart disease in the United States have declined from 187 deaths per 100,000 population in 2000 to 123 deaths per 100,000 in 2008 [2]. High-technology care includes coronary care unit, cardiac surgery, and devices such as implantable defibrillators and circulatory support pumps. Low-technology care includes medical therapy for hypertension and hypercholesterolemia, as well as aspirin prophylaxis in appropriate patients. Behavioral changes include declines in cigarette smoking and changes in dietary fat intake. For identifying all three of these areas - high-technology care, low-technology care, and behavioral change - we can confidently say that biomedical research played a critical role. Were it not for biomedical research, coronary heart disease mortality rates might well be nearly four times higher (405,000/1,579,000) in the United States [2]. Cutler and Kadiyala estimate that the societal rate of return on biomedical research and cardiovascular disease is at least 4 to 1 [1]. Cardiovascular research, at least in high-income countries, has been an outstanding investment [3]. Given the large burden of cardiovascular disease in low- and middle-income countries, the persistent use of solid fuels globally, and the hypothesized cardiovascular effects of solid fuel smoke, we see a window of opportunity for research that could lead to positive impacts on public health practice and policy.