Wood stoves may up lung cancer risk in women

NEW YORK (Reuters Health) - Women who have been exposed to traditional, potentially polluting heating and cooking fuels in the home such as cool and wood appear to have an increased risk of developing lung cancer, a study suggests.

"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 explain in the American Journal of Epidemiology. "Concern is increasing that use of polluting heating and cooking sources can increase cancer risk."

The researchers surveyed a group of people diagnosed with lung cancer between 1996 and 1997 and a group of randomly selected cancer-free controls. The subjects were asked if they had ever lived in homes where the heating or cooking involved coal, wood or gas.

Questionnaires were completed by 1,205 lung cancer patients (739 men and 466 women) and 1,541 controls (925 men and 616 women).

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.

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

In contrast, among women exposure to coal, wood or gas heating or cooking sources was associated with a 2.5-fold increased odds of lung cancer.

"As with any other finding from a single epidemiologic study, we must be cautious in drawing firm conclusions," 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," Siemiatycki said, "and we should favor appliances which are efficient and clean -- and that ventilation is important."

For the moment, "there is no reason for anybody to panic about their past or present exposure to traditional fuels," 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.

SOURCE: American Journal of Epidemiology, March 2007.