Never-Smoking Chinese Urban Women: A Hospital-Based Matched Case Control Study. PLoS ONE 9(5)...

Background: The relationship between passive smoking exposure (PSE) and breast cancer risk is of major interest. Objective: To evaluate the relationship between PSE from partners and breast cancer risk stratified by hormone-receptor (HR) status in Chinese urban women population. Design: Hospital-based matched case control study. Setting: Chinese urban breast cancer patients without current or previous active smoking history in China Medical University 1st Hospital, Liaoning Province, China between Jan 2009 and Nov 2009. Patients: Each breast cancer patient was matched 1:1 with healthy controls by gender and age (62 years) from the same hospital. Measurements: The authors used unconditional logistic regression analyses to estimate odds ratio for women with PSE from partners and breast cancer risk. Results: 312 pairs were included in the study. Women who endured PSE had significantly increased risk of breast cancer (adjusted OR: 1.46; 95 % CI: 1.05–2.03; P = 0.027), comparing with unexposed women. Women who exposed to.5 cigarettes/day also had significant increased risk (adjusted OR: 1.99; 95 % CI: 1.28–3.10; P = 0.002), as were women exposed to passive smoke for 16–25 years (adjusted OR: 1.87 95 % CI: 1.22–2.86; P = 0.004), and those exposed to. 4 pack-year