BACKGROUND: Smoking has been associated with cervical cancer. We examined whether smoking increases the risk for high-grade cervical lesions in women with high-risk human papillomavirus (HPV) infection. METHODS: In a population-based cohort study, 8,656 women underwent a structured interview, and subsequently cervical cells were obtained for HPV DNA testing. Women with high-risk HPV infection and no prevalent cervical disease at baseline (n=1,353) were followed through the Pathology Data Bank for cervical lesions for up to 13 years. Separate analyses of women with persistent high-risk HPV infection were also conducted. Hazard ratios (HRs) for a diagnosis of cervical intraepithelial neoplasia grade 3 or worse/high-grade squamous intraepithelial lesions or worse (CIN3+) and the corresponding 95% confidence intervals (CIs) were calculated in the 2 groups. RESULTS: Among high-risk HPV positive women an increased risk for CIN3+ was associated with long-term smoking (=10 years) and heavy smoking (=20 cigarettes/day). In the subgroup of women with persistent HPV infection heavy smoking was also associated with statistically significantly higher risk for CIN3+ than never smoking (HR, 1.85; 95% CI, 1.05-3.22, adjusted for length of schooling, parity and HPV type at baseline). The average number of cervical cytology screening tests per year during follow-up did not explain the differences in risk in relation to smoking (p=0.4). CONCLUSIONS: Smoking is associated with an increased risk for subsequent high-grade cervical lesions in women with persistent high-risk HPV infection. Impact: Our study adds to the understanding of the role of smoking in the natural history of HPV and cervical carcinogenesis.
Cancer Epidemiology, Biomarkers and Prevention, 2012, Vol 21, Issue 11, p. 1949-1955