Type-specific HPV infection and multiple HPV types: Prevalence and risk factor profile in nearly 12,000 younger and older Danish women

Objectives: Human papillomavirus (HPV) is considered a necessary cause of cervical cancer. The aim of the current study was to determine the burden of HPV infection among randomly sampled Danish women before the vaccine against HPV is implemented. Further we assessed the risk factor profile for prevalent high risk (HR) HPV infection and infection with multiple HR HPV types. Methods: In the present cross-sectional study, we used baseline data from a population-based cohort study where participants were interviewed and had a gynecological examination. Cervical samples were analyzed for HR HPV using Hybrid capture 2 in 10,544 women aged 20-29 years and 1443 women aged 40-50 years. Genotyping was performed using LIPA. Results: The prevalence of HR HPV was 17.9% and 4.4% in women aged 20-29 years and 40-50 years, respectively. HPV16 was the most common HR type overall and among women with abnormal cytology. Multiple HPV types were highly prevalent, notably in the younger cohort. Lifetime number of sexual partners was the main risk factor for HR HPV infection (adj. OR = 2.8 and OR = 3.4 for >= 15 partners vs. <= 4 in respectively younger and older women), whereas number of recent sexual partners was only associated with risk in younger women. Number of partners, oral contraceptive use and self-reported chlamydia infection increased the risk of having multiple HR HPV types (compared to having a single HR HPV type). Conclusions: HR HPV infection was common among younger women, with HPV16 as the predominant type. We confirmed the importance of sexual activity for the risk of HR RPV infection. In addition, we found that sexual behavior also play an important role for the risk of having multiple HR HPV types.