Smoking increased risk of cervical cancer, independent of infection with high-risk HPV types
Question
Is smoking an independent risk factor for cervical cancer, after controlling for infection with high-risk types of human papillomavirus (HPV)?
Methods
Design:
nested case–control study within a prospective cohort study.
Setting:
5 population-based serum banks in 4 Nordic countries, consisting of serum samples from >1 million women, most collected during early pregnancy.
Patients:
cases were 588 women diagnosed with invasive cervical cancer after their serum sample had been banked (mean age at diagnosis 34–56 y). Controls were 2861 women who were free of cancer at the time of the corresponding case’s diagnosis, matched to cases (5 per case) by bank, age at sampling, storage time of sample, and county (in Norway).*
Risk factors:
smoking status as assessed by serum cotinine concentration: <20 ng/ml (non-smokers and women passively exposed), 20 to <100 ng/ml (light smokers), and ⩾100 ng/ml (heavy smokers), with adjustment for presence …
