Risk factors for primary lung cancer among non-smoking women in Taiwan.

BACKGROUND Although cigarette smoking is considered to be the most important cause of lung cancer, smoking behaviour cannot fully explain the epidemiological characteristics of lung cancer in Taiwanese women, who rarely smoke but contract lung cancer relatively often. There are other causes of lung cancer that have produced variability in lung cancer incidence. METHODS A case-control study involving interviews with 117 female patients (including 106 non-smoking) suffering from lung cancer and the same number of individually matched hospital controls was conducted in Kaohsiung, Taiwan between 1992 and 1993. The questionnaire administered to cases and controls collected information on cigarette smoking and suspected risk factors for lung cancer. Multivariate logistic regression analysis was applied to assess smoking for all women and suspected risk factors for non-smoking women. RESULTS The relationship between cigarette smoking and lung cancer was statistically significant although only a small proportion (9.4%) of female patients had smoked. However, the risk of contracting cancer for non-smoking women appears to be associated with certain cooking practices, especially preparing meals in kitchens not equipped with a fume extractor at cooking age of 20-40 years (odds ratio [OR] = 8.3; 95% confidence interval [CI]: 3.1-22.7. These factors and a history of pulmonary tuberculosis plus low consumption of fresh vegetables explained 78% of the summary attributable risks for non-smoking women in a multivariate logistic regression model. CONCLUSIONS Exposure to fumes from cooking oils, when not reduced by an extractor, may be an important factor in causing lung cancer in non-smoking Taiwanese women.