Research Opportunities for Cancer Associated with Indoor Air Pollution from Solid-Fuel Combustion

Article excerpt

BACKGROUND: Indoor air pollution (IAP) derived largely from the use of solid fuels for cooking and heating affects about 3 billion people worldwide, resulting in substantial adverse health outcomes, including cancer. Women and children from developing countries are the most exposed populations. A workshop was held in Arlington, Virginia, 9-11 May 2011, to better understand women's and children's potential health effects from IAP in developing countries. Workshop participants included international scientists, manufacturers, policy and regulatory officials, community leaders, and advocates who held extensive discussions to help identify future research needs.

OBJECTIVES: Our objective was to identify research opportunities regarding IAP and cancer, including research questions that could be incorporated into studies of interventions to reduce IAP exposure. In this commentary, we describe the state of the science in understanding IAP and its associations with cancer and suggest research opportunities for improving our understanding of the issues.

DISCUSSION: Opportunities for research on IAP and cancer include studies of the effect of IAP on cancers other than lung cancer; studies of genetic factors that modify susceptibility; studies to determine whether the effects of IAP are mediated via germline, somatic, and/or epigenetic changes; and studies of the effects of IAP exposure via dermal and/or oral routes.

CONCLUSIONS: IAP from indoor coal use increases the risk of lung cancer. Installing chimneys can reduce risk, and some genotypes, including GSTM1-null, can increase risk. Additional research is needed regarding the effects of IAP on other cancers and the effects of different types of solid fuels, oral and dermal routes of IAP exposure, genetic and epigenetic mechanisms, and genetic susceptibility.

KEY WORDS: cancer, environmental exposures, environmental health risks, epidemiology, household air pollution, indoor air pollution, public health, solid-fuel combustion. Environ Health Perspect 120:1495-1498 (2012). [Online 30 July 2012]

Despite considerable research on cancer and indoor air pollution (IAP) [International Agency for Research on Cancer (IARC) 2010], additional targeted research is needed in this area. In this commentary, we describe the state of the science in understanding IAP and its associations with cancer and suggest research opportunities to improve our understanding of the issues.

A workshop held in Arlington, Virginia, 9-11 May 2011, titled the "Health Burden of Indoor Air Pollution on Women and Children in Developing Countries," was sponsored by several U.S. federal agencies and the Global Alliance for Clean Cookstoves, a public-private partnership led by the United Nations Foundation (Washington, DC). Stakeholders attending the plenary sessions included a wide array of international scientists, product developers, nongovernmental organization officials, and regulatory and policy officials, as well as community leaders and advocates from the most affected regions in Africa, India, Latin America, and China. The workshop focused on identifying research gaps concerning major health issues related to IAP. For this report we retain the use of the term "indoor air pollution" in keeping with the title of the workshop, but wish to acknowledge that the term "household air pollution" is preferred by many as more accurate in accounting for the sources of the pollution.

Exposure to IAP from the use of solid fuels is a significant public health concern affecting approximately 3 billion people worldwide and associated with an estimated 2 million deaths in the year 2000 alone (Ezzati et al. 2004; IARC 2010; World Health Organization 2009). The predominant forms of solid fuels include coal and various forms of biomass such as wood, charcoal, animal dung, and agricultural waste. Use of coal for cooking and heating is relatively uncommon globally, although it remains quite important in China and parts of central Asia (Rehfuess et al. …