To evaluate the relation between smoking, alcohol drinking and risk of breast cancer in Chinese women, we conducted a case-control study with 669 cases and 682 population-based controls in Jiangsu Province of China. A structured questionnaire was used to elicit detailed information. Unconditional logistic regression analysis was performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs). The results revealed that smoking, whether active or passive through the husband, was related to increased risk of breast cancer. The ORs (adjusted for age, menopausal status, educational levels, occupation, body mass index and income) were 3.55 (95%CI: 1.27-9.91) for active smoking and 1.47 (95%CI: 1.18-1.84) for passive smoking from husbands, respectively. A significant positive relationship was observed between breast cancer risk and the degree of husbands' smoking. There were significant increase trend in ORs with the daily smoked number of cigarettes of husbands, the passive smoking years from husbands and the pack-years of husbands' smoking (trend test: p=0.00003, 0.00013 and 0.0001, respectively). Alcohol consumption was also found to be a risk factor. The findings of this study in particular suggest that husbands' smoking increases risk of breast cancer in Chinese women.
