| Cervical cancer is the second most common cancer in women worldwide. Persistent human papillomavirus (HPV) infection has been implicated in cervical carcinogenesis. Thus, identification of risk factors for HPV persistence may facilitate cervical cancer prevention efforts by targeting women at increased risk of persistent HPV infection, and therefore cervical disease, for more frequent screening and intervention as needed. Smoking has been associated with cervical cancer in HPV DNA-positive women, but its association with HPV persistence is unclear. In addition, certain high-risk HPV types, such as HPV16, may be more persistent than others, and type-specific HPV persistence could differ by HIV serostatus. This study evaluated the effect of smoking and HPV type on clearance of HPV infections among 522 HIV-seropositive and 279 HIV-seronegative women from the HIV Epidemiology Research Study, a federally funded multi-site US cohort study (1993-2000). Hazard ratios (HR) adjusted for study site and risk behavior (sexual or injection drugs) were estimated using Cox regression. Current smoking was not associated with overall type-specific HPV clearance in HIV-seropositive (HR: 0.99, 95% confidence intervals (CI): 0.82, 1.20) or HIV-seronegative women (HR: 0.93, 95% CI: 0.68, 1.26). Ever smoking appeared to decrease high-risk HPV clearance in HIV-seronegative (HR: 0.51, 95% CI: 0.30, 0.88), but not HIV-seropositive women (HR: 0.96, 95% CI: 0.65, 1.42). High-risk HPV results were similar for current smoking and did not clearly differ with amount or duration of smoking. The HRs for HPV16 and related type clearance versus low-risk HPV infections were 0.80 (95% CI: 0.67-0.96), 0.79 (95% CI: 0.64-0.97), and 0.86 (95% CI: 0.59-1.27) for all, HIV-seropositive, and HIV-seronegative women, respectively. The HRs for clearance of HPV18 and related types versus low-risk HPV infections were 0.88 (95% CI: 0.71-1.10), 0.86 (95% CI: 0.67-1.11), and 1.01 (95% CI: 0.62-1.64) for all, HIV-seropositive, and HIV-seronegative women, respectively. Smoking did not modify overall clearance but ever smoking was associated with lower high-risk HPV clearance in HIV-seronegative women. HIV serostatus did not appear to have an effect on the HRs for clearance by HPV type. Thus, clearance of HPV infections seemed to be influenced by smoking in HIV-seronegative women and by HPV type. |
