Residential Fuel Exposure May Increase Lung Cancer Risk

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NEW YORK (Reuters Health) Mar 22 - Women who have been exposed to traditional residential heating and cooking fuels appear to have an increased risk of lung cancer, according to findings published in the March issue of the American Journal of Epidemiology.

"Among the major sources of indoor air pollution are combustion by-products from heating and cooking," Dr. Jack Siemiatycki, of the University of Montreal, Quebec, and colleagues write. "Concern is increasing that use of polluting heating and cooking sources can increase cancer risk."

The researchers surveyed patients diagnosed with lung cancer between 1996 and 1997 and controls randomly selected from the population. The subjects were asked if they had ever lived in homes where the heating or cooking was based on 'traditional," potentially polluting fuels such as coal, wood or gas. Questionnaires were completed by 1205 lung cancer patients (739 men and 466 women) and 1541 controls (925 men and 616 women).

The team computed odds ratios using indices of exposure to traditional heating and cooking sources. The data were adjusted for a number of covariates, including smoking, age and exposure to other pollutants.

Most of the subjects who had been exposed to these heating and cooking sources were exposed before the age of 20 years and for more than 10 years. Most were exposed to both traditional cooking and traditional heating sources.

No associations between traditional heating or traditional cooking sources and increased risk of lung cancer were found among the men.

In contrast, among women there were strong associations between lung cancer risk and heating or cooking sources. For the 253 women exposed to both traditional heating and cooking sources, the odds ratio was 2.5.

The association by histological type was strongest for small cell and squamous cell carcinoma, and weakest for adenocarcinomas.

"As with any other finding from a single epidemiologic study, we must be cautious in drawing firm conclusions," Dr. Siemiatycki said in an interview with Reuters Health. "There is the possibility that chance or study biases may explain these observations," he explained, and "we need to wait for corroboration" confirming a "true causal relationship."

"If so, the clinical implication is that indoor pollution caused by traditional fossil fuels is a cancer risk, and we should favor appliances that are efficient and clean -- and that ventilation is important."

"There is no reason for anybody to panic about their past or present exposure to traditional fuels," Dr. Siemiatycki added. The association is not confirmed "and we do not have a firm quantitative estimate of its impact, if it is real," he noted.

Am J Epidemiol 2007;165:634-642.

Source: http://www.medscape.com/viewarticle/554006?src=mp