RE: “LUNG CANCER AND INDOOR POLLUTION FROM HEATING AND COOKING WITH SOLID FUELS: THE IARC INTERNATIONAL MULTICENTRE CASE-CONTROL STUDY IN EASTERN/CENTRAL EUROPE AND THE UNITED KINGDOM”

In their excellent and historical study on solid fuel use and lung cancer in Eastern/Central Europe and the United Kingdom, Lissowska et al. (1) found that cooking or heating with solid fuel increases risk for lung cancer and suggest that cooking with wood carries a higher risk than does cooking with coal. We got interested in the last point for two reasons. First, the evidence of association between lung cancer and exposure to smoke from wood combustion is not yet sufficiently robust (2), and this paper adds to the growing literature on the subject. Second, if cooking with wood carries a higher risk, then one would expect that lung cancer (in addition to chronic obstructive pulmonary disease and acute respiratory infections) should be a major public health problem, especially among women, in many developing societies that depend heavily on wood for cooking. Their findings may be related to the way exposure was assessed, because the real determinants of exposure to smoke from solid fuel combustion are time spent around the source of smoke and particulate matter concentration in the same microenvironment (3). The use of solid fuels in homes or the percentage of time spent in homes as a proxy for exposure is unlikely to accurately capture the level of exposure. Parameters such as ventilation level in the cooking microenvironment, house characteristics, and household cooking preferences are important to the extent that households using solid fuel may not necessarily be more exposed than are households using cleaner fuels (4). We suggest that the risk estimates stated in the paper of Lissowska et al. (1) be interpreted with caution and that future case-control studies on solid fuel use and cancer should raise as many data as possible on houseand householdspecific parameters. Such parameters that can affect ventilation level are needed for the adjustment of risk estimates. ACKNOWLEDGMENTS