Cruciferous vegetables consumption and the risk of female lung cancer: a prospective study and a meta-analysis

Background: Epidemiological studies evaluating the association between cruciferous vegetables (CVs) intake and female lung cancer risk have produced inconsistent results. Patients and methods: This study followed 74 914 Chinese women aged 40-70 years who participated in the Shanghai Women's Health Study. CV intake was assessed through a validated food-frequency questionnaire (FFQ) at baseline and reassessed during follow-up. Hazard ratios (HRs) and 95% confidence interval (as) were estimated by using Cox proportional hazards models. Furthermore, we carried out a meta-analysis of all observational studies until December 2011. Results: After excluding the first 2 years of follow-up, 417 women developed lung. cancer over a mean of 11.1 years of follow-up. An inverse association of borderline statistical significance was observed between CV consumption and female lung cancer risk, with HR for the highest compared with the lowest quartiles of 0.73 (95% CI 0.54-1.00, P trend = 0.1607). The association was strengthened in analyses restricting to never smokers, with the corresponding HR of 0.59 (95% CI 0.40-0.87, P trend = 0.0510). The finding of an inverse association between CV intake and lung cancer risk in women was supported by our meta-analysis of 10 included studies. Conclusions: Our study suggests that CV consumption may reduce the risk of lung cancer in women, particularly among never smokers.