Such stove improvement may benefit the health of people in other developing countries as well, conclude Qing Lan, M.D., Ph.D., of the Chinese Academy of Preventive Medicine and the National Cancer Institute, and Robert S. Chapman, M.D, M.P.H., of the U.S. Environmental Protection Agency, and their colleagues.

Household cooking and heating using unvented indoor stoves is a common practice in developing countries. This often involves burning coal or wood and can produce high levels of indoor air pollutiona risk factor for lung cancer and other lung diseases.

Past studies have shown that stove improvements such as installing chimneys can substantially reduce indoor air pollution. However, it has not been clear whether such reduction is associated with a reduced risk of lung disease.

In this retrospective study of 21,232 farmers in Xuanwei, China, the authors compared the incidence of lung cancer among 17,184 farmers who switched from unvented firepits or stoves to stoves with chimneys with the incidence of lung cancer among 4,048 farmers who continued to use unvented firepits or stoves. Tobacco smoking and frequency of cooking were similar in both groups.

The authors found that levels of indoor air pollution created by vented burning were less than 35% of levels created by unvented burning. After adjusting for factors such as tobacco smoking and duration of cooking, the authors found that changing from unvented to vented stoves was associated with a 41% reduction in lung cancer risk in men, and a 46% reduction in lung cancer risk in women.

The authors conclude that changing from unvented burning to stoves with chimneys was strongly associated with a reduction in
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Contact: Linda Wang
jncimedia@oupjournals.org
301-841-1287
Journal of the National Cancer Institute
4-Jun-2002