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I I I I I I I I I I I t I i I I I I PASSIVE SMOKING AND LUNG CANCER AMONG NONSMOKING WOMEN IN HARBIN, CHINA Sun Xi-w i, Dai Xu-dong, Lin Chun-Yan, Shi Yu-bo, Ma Yu-Yan and Li Wei Heilongjiang Cancer Research Institute, Harbin, China. Previous epidemiologic studies reporting an association between the exposure of nonsmoking women to environmental tobacco smoke (ETS) and an increase in the risk of lung cancer have produced inconsistent data. This report describes a recent population-based case-control study conducted in the city of Harbin in China which attempts to further clarify the possible relationship between exposure to ETS and the risk of lung cancer in "never-smoking" women. Two hundred and thirty cases of lifetime nonsmoking females with histologically confirmed primary lung cancer and an equal number of lifetime nonsmoking controls randomly identified from the population by a stratified method, were interviewed in person by trained interviewers. Items considered in the analysis were (1) exposure to ETS during childhood (before 8 years of age), adolescence (between 9-18 years of age), and adulthood, (2) exposure to ETS in the household and in the workplace, and (3) exposure to ETS from household members. Logistic regression analysis was used to estimate age- and education-adjusted odds ratios (ORs) and 95% confidence intervals (CI). The Chi-square test was used to test for trend. The risk of lung cancer was significantly higher for women who reported exposure to ETS in both the household and the workplace (OR= 2.92, 95%CI: 1.89-4.49); during childhood (OR=2.29, 95%Cl: 1.56-3.37); during adolescence (OR=2.60, 95%CI: 1.77-3.83); and during adulthood (OR= 1.83, 95%CI: 1.20-2.80). Although an increase in the risk of lung cancer was associated with reported exposure to maternal smoking (OR= 2.05, 95%CI: 1.29-3.27) and to paternal smoking (OR= 2.35, 95%Cl: 1.56-3.54), no association was reported for exposure to spousal smoking (OR= 1.16, 95%Cl: 0.80-1.69). Women who lived with husbands who smoked for >35 years had odds ratio of 0.86, 95%Cl: 0.45-1.65. The total number of reported years of exposure to ETS and the amount of lifetime exposure to ETS in the home were statistically significantly associated with the risk of developing lung cancer. All histologic types of lung cancer were significantly increased in subjects reporting exposure to ETS in both the household and in the workplace (for adenocarcinoma, OR= 2.86, 95%CI: 1.69-4.84; for squamous and small cell carcinoma, OR= 2.06, 95%CI: 1.03-4.15; for other types of lung cancer, OR= 4.87, 95%CI: 1.95-12.19). When only exposure to a household member's smoking was considered, no significant differences were reported between cases and controls. Women who only reported exposure to ETS in the workplace had a non-statistically significant elevated risk of lung cancer (OR= 1.38, 95%CI: 0.94-2.04). These data suggest that long-term exposure to ETS is associated with an increase in the risk of lung cancer in "never-smoking" women. Moreover, the risk appears to be higher when the exposure occurs during childhood and adolescence than when it occurs in adulthood. t