The effect of polygamy on loss of human papillomavirus detection in Senegalese women

Thesis (Master's)--University of Washington, 2021Objectives: Persistent infection with human papillomavirus (HPV) can result in premalignant cervical lesions. Women in polygamous marriage are more likely to be re-exposed to HPV. Repeated exposure to HPV antigen may lead to shorter duration of infections by boosting the immune response. This study assessed the impact of polygamy on the clearance of HPV infection and assessed whether this association varies by HIV status or coinfection with multiple HPV types.Methods: We used secondary data collected in two prospective cohort studies (between 1994-1998 and 2005-2011) conducted in Senegal, western Africa. Subjects were females aged 15 years or older, were married, were not pregnant, had an intact cervix, were HPV- positive at baseline or during 4-6 month follow-up visits, and with at least 2 follow-up visits following initial detection of HPV (n=235). The unit of analysis was each infection (288 prevalent infections and 290 incident infections). We conducted marginal Cox proportional hazard regression models to investigate the impact of polygamous marriage versus monogamous marriage on the clearance of HPV infection, adjusting for age, parity, lifetime number of sex partners, infection status (prevalent or incident), HIV status (HIV positive with 350 cells/μL CD4 count; HIV positive with < 350 cells/μL CD4 count; HIV negative) and coinfection with other HPV types. We further assessed the effect modification of HIV status and coinfection with multiple HPV types. Results: We included 289 infections that occurred among polygamously married women, and 289 infections that occurred among monogamously married women. Polygamously married subjects tended to be older, were more often HIV negative, had more children, and had a higher lifetime number of sex partners. We did not identify an association between polygamous marriage and HPV clearance (HR:0.97, 95% CI: 0.70-1.34). HIV status didn’t modify this association (p-value=0.28). We observed a non-statistically significant positive association between polygamous marriage and HPV clearance (HR: 1.47, 95% CI: 0.82-2.65) in HIV positive women with 350 cells/μL CD4 counts, but not in HIV negative women (HR: 0.84, 95% CI: 0.57-1.19) or HIV positive women with < 350 cells/μL CD4 counts (HR: 0.88, 95% CI: 0.35-2.19). Coinfection with multiple HPV types was not an effect modifier (p-value=0.97). Conclusion: We conclude that polygamous marriage wasn’t associated with HPV clearance, but there was a non-significantly positive association between marital status and HPV clearance. The potential reason for this difference may be the different sexual behavior or varied immune function among women by HIV status. This finding provides potential evidence of the re-exposure-related immune responses to HPV clearance