Passive Smoking and Cervical Cancer Risk: A Meta-analysis Based on 3,230 Cases and 2,982 Controls

OBJECTIVE: Passive smoking has been considered as a risk factor of many cancers. To examine whether it might also pose a risk for cervical cancer, we performed a meta-analysis based on published case-control studies. METHODS: We searched the PubMed database and references of included studies up to February 10th, 2012 for relevant studies. After two authors independently assessed the methodological quality and extracted data, a meta-analysis was conducted using CMA v2 software. Publication bias was evaluated by funnel plot, using Egger's and Begg's tests. RESULTS: Finally 11 eligible studies yielded, involving 3,230 cases and 2,982 controls. The results showed that women who never smoke but exposed to smoking experience a 73% increase in risk of cervical cancer compared with non-exposed women (OR = 1.73, 95% CI = 1.35 - 2.21, p<0.001). Subgroup and sensitivity analyses indicated this result to be robust. Moderate publication bias was detected by visualing funnel plot, Egger's and Begg's tests. CONCLUSION: Based on currently available evidence, the findings of this meta-analysis suggests that passive smoking significantly and independently increases the risk of cervical cancer.