Gender susceptibility for cigarette smoking-attributable lung cancer: A systematic review and meta-analysis

Abstract Objectives As the primary cause of lung cancer, whether smoking confers the same risk of lung cancer for women as men is unclear. Therefore, we aimed to compare male and female susceptibility for cigarette smoking-attributable lung cancer. Methods A systematic review and meta-analysis was conducted by searching articles published up to July 2013 in three online databases (MEDLINE, EMBASE, and Cochrane Database). All studies estimated the association of cigarette smoking with the risk of lung cancer between men and women, respectively. A random effects model with inverse variance weighting was used to pool data. Male to female ratio of relative risk (RRR) was calculated to compare male and female susceptibility for cigarette smoking-attributable lung cancer. Results 47 articles containing 404,874 individuals were included in the final analysis. Compared with non-smokers, male to female RRR was 1.61 (95%CI: 1.37, 1.89) among current smokers. Based on pathological type, adenocarcinoma had the highest RRR (1.42; 95%CI: 0.86, 2.35), followed by squamous cancer and small cell lung cancer. Furthermore, compared with non-smoking men, current smoking men had higher risk of lung cancer than women in spite of smoking quantity, smoking duration or years since quitting. Conclusions These findings indicated that males had higher susceptibility for cigarette smoking-attributable lung cancer than females. It is contradicted with traditional opinion that females would be more easily suffered from cigarette smoking-attributable health problems than males. Hence, tobacco control is very crucial in both males and females.