Active and passive smoking with breast cancer risk for Chinese females: a systematic review and meta-analysis.
Previous studies suggested that smoking and passive smoking could increase the risk of breast cancer, but the results were inconsistent, especially for Chinese females. Thus, we systematically searched cohort and case-control studies investigating the associations of active and passive smoking with breast cancer risk among Chinese females in four English databases (PubMed, Embase, ScienceDirect, and Wiley) and three Chinese databases (CNKI, WanFang, and VIP). Fifty-one articles (3 cohort studies and 48 case-control studies) covering 17 provinces of China were finally included in this systematic review. Among Chinese females, there was significant association between passive smoking and this risk of breast cancer [odds ratio (OR): 1.62; 95% confidence interval (CI): 1.39-1.85; I2 = 75.8%, P < 0.001; n = 26] but no significant association between active smoking and the risk of breast cancer (OR: 1.04; 95% CI: 0.89-1.20; I2 = 13.9%, P = 0.248; n = 31). The OR of exposure to husband's smoking and to smoke in the workplace was 1.27 (95% CI: 1.07-1.50) and 1.66 (95% CI: 1.07-2.59), respectively. The OR of light and heavy passive smoking was 1.11 and 1.41, respectively, for women exposed to their husband's smoke (< 20 and ≥ 20 cigarettes per day), and 1.07 and 1.87, respectively, for those exposed to smoke in the workplace (< 300 and ≥ 300 min of exposure per day). These results imply that passive smoking is associated with an increased risk of breast cancer, and the risk seems to increase as the level of passive exposure to smoke increases among Chinese females. Women with passive exposure to smoke in the workplace have a higher risk of breast cancer than those exposed to their husband's smoking.
Department of Epidemiology and Biostatistics, Tianjin Medical University Cancer Hospital and Institute, National Clinical Research Center for Cancer, Tianjin & Key Laboratory of Cancer Prevention and Therapy, Tianjin & Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, P. R. China. chenkexin1963@yahoo.com.
Chuan
C
Chen
Yu-Bei
YB
Huang
Xue-Ou
XO
Liu
Ying
Y
Gao
Hong-Ji
HJ
Dai
Feng-Ju
FJ
Song
Wei-Qin
WQ
Li
Jing
J
Wang
Ye
Y
Yan
Pei-Shan
PS
Wang
Yao-Gang
YG
Wang
Ke-Xin
KX
Chen
D001943:Breast Neoplasms; D002681:China; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016273:Occupational Exposure; D016017:Odds Ratio; D012307:Risk Factors; D012907:Smoking; D014028:Tobacco Smoke Pollution
D014028:Tobacco Smoke Pollution