Smoking tobacco is the major risk factor for developing lung cancer. However, most Han Chinese women with lung cancer are nonsmokers. Chinese cooking methods usually generate various carcinogens in fumes that may inevitably be inhaled by those who cook the food, most of whom are female. We investigated the associations of cooking habits and exposure to cooking fumes with lung cancer among non-smoking Han Chinese women. This study was conducted on 1,302 lung cancer cases and 1,302 matched healthy controls in Taiwan during 2002-2010. Two indices, "cooking time-years" and "fume extractor use ratio," were developed. The former was used to explore the relationship between cumulative exposure to cooking oil fumes and lung cancer; the latter was used to assess the impact of fume extractor use for different ratio-of-use groups. Using logistic models, we found a dose-response association between cooking fume exposure and lung cancer (odds ratios of 1, 1.63, 1.67, 2.14, and 3.17 across increasing levels of cooking time-years). However, long-term use of a fume extractor in cooking can reduce the risk of lung cancer by about 50%. Furthermore, we provide evidence that cooking habits, involving cooking methods and oil use, are associated with risk of lung cancer. Lung cancer has been the leading cause of cancer death for women worldwide, including in Taiwan 1,2. The incidence trend of lung cancer has increased steadily in Taiwan 2. It is well known that cigarette smoking is the major cause of lung cancer 3,4. However, unlike for Western populations, the epidemiological features of lung cancer in Han Chinese women cannot be elucidated fully by smoking behavior 5,6 , because the majority of Han Chinese female lung cancer cases have been nonsmokers 5,7-12. In fact, in Taiwan about 9-10% of females with lung cancer and 79-86% of males with lung cancer were tobacco smokers 13-15. The discrepancy in tobacco usage for female and male lung cancer patients in Taiwan suggests that other potential risk factors linked to lung cancer for non-smoking women might require further investigation.

These results suggest that genetic variants in CYP1A2 may be indicators for S-CIT metabolism and that the fast metabolizers may experience more severe adverse reactions in the early stages of S-CIT treatment. Original submitted 27 December 2012; Revision submitted 15 May 2013.

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