Epidemiologic risk profile of infection with different groups of human papillomaviruses

This study identified the age-specific prevalence and epidemiologic risk profile for infection with different groups and species of human papillomaviruses (HPV). Structured interview and HPV testing were conducted for 2,604 Chinese women self-referred for cervical screening. Independent risk factors for infection were identified by multiple logistic regressions. Overall, a major peak of HPV infection was observed at women aged 26-30 years, and a minor peak at 46-55 years. This pattern was observed for high-risk, low-risk, and alpha-5/7/9 HPVs; but alpha-3/6 HPVs showed peaks of similar magnitudes in young and older women. Independent risk factors for HPV infection (all types combined) included younger age (OR [95% CI] for >55 vs. < or =30 years = 0.22 [0.09-0.55]; 31-45 vs. < or = 30 years = 0.57 [0.33-0.99]), having > or =4 lifetime sexual partners (2.28 [1.06-4.88]), and smoking (2.24 [1.22-4.10]). Young age and smoking were the most consistent independent risk factors observed across different HPV groups. The risk profile for high-risk HPV was similar to alpha-5/7/9. Single-type infection was associated with having more sexual partners, higher education level and oral contraception; whereas multiple-type infection was associated with smoking. In conclusion, a U-shaped age-specific prevalence curve was observed for HPV infection overall, but with a different pattern for different HPV species. Different HPV groups showed variations in their risk profiles. These data are useful for formulating preventative strategy for HPV-related diseases. Catch-up vaccination program in Hong Kong should cover a wider age group as the first peak of infection occurred relatively late.