Women and children suffer most from exposure to coal smokeBMJ 2006; 333 doi: http://dx.doi.org/10.1136/bmj.39052.492639.DB (Published 07 December 2006) Cite this as: BMJ 2006;333:1192
The burning of coal and of biomass fuels such as wood, straw, and cow dung in conditions of poor ventilation increases the risk of lung cancer, a report from the International Agency for Research of Cancer concludes.
The agency's report, from a meeting in October of 19 scientists from eight countries, says that frying at high temperatures—including stir frying, deep frying, and pan frying—also increases the risk of the disease, regardless of the type of cooking oil used (Lancet Oncology 2006;7:977-8).
The risk of lung cancer from breathing in coal smoke in the workplace has long been studied; but until recently conclusive evidence on the effect of exposure in the home had not been established. Around half the people in the world burn solid fuels to cook or heat their homes, and ventilation is often poor in the interior spaces in which the fuels are used. Products of incomplete combustion include carcinogens such as benzo[a]pyrene, formaldehyde, and benzene.
People who are exposed the most to such carcinogens are those who are at home the most: women and young children. Peter Boyle, director of the agency, which is part of the World Health Organization, notes that exposure to these fuels “are experienced daily by hundreds of millions worldwide.” In sub-Saharan Africa, for example, more than 90% of households burn solid fuels.
One solution is to build chimneys to ventilate better the spaces in which the coal or biomass fuel is burned, the report says.
The agency's group of scientists also assessed studies relating to cooking in which cooking oil is heated to high temperatures. Although such cooking methods are used around the world they are especially common in China, where several of the studies under review took place.
Studies conducted in Hong Kong and Shanghai found that all methods of high temperature frying seemed to increase the risk of lung cancer, although one study from rural Gansu province, in central China, showed that stir frying but not deep frying increased the risk of the disease.
The results of the agency's evaluation were presented at a meeting of the Society for Risk Analysis in Baltimore, Maryland, on 4 December.
WHO has stated that indoor smoke from burning solid fuel is one of the world's top 10 risk factors for disease.