Environmental Tobacco Smoke And Risk Of Breast Cancer

Introduction. Even though it is well understood that tobacco smoking has substantial and adverse effects on human health, the role of environmental tobacco smoke (ETS) on breast cancer (BC) remains unclear. This study aimed to examine the association between ETS exposure at home and the risk of BC. Methods. A hospital-based case-control study was carried out in 585 cases and 1170 controls. Information on ETS at home and other possible risk factors was collected via a structured questionnaire. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for BC by exposure to ETS. All statistical tests were two-sided. Results. Women, who never smoked actively but had ever experienced exposure to ETS at home in life had a 2-fold increased risk of BC compared with non-smokers without exposure to ETS at home (OR = 2.11 95% CI = 1.63-2.74, p < 0.001), after adjustment for age, education, marital status, family history on breast cancer, number of given births, estrogen-active period, hormone therapy during menopause, alcohol use, body mass index, diabetes mellitus, and thyroid diseases. However, the association between BC risk and exposure to ETS in ex-smokers or current smokers was not defined (OR = 0.98 95% CI = 0.48-2.0, p = 0.954 and OR = 1.06 95% CI = 0.53-2.14, p = 0.86, respectively). Conclusion. The data obtained show increased risk of breast cancer in never smoked women exposed to environmental tobacco smoke at home in their life.