Background: Persistent infection with high risk HPV is a necessary but insufficient cause of cervical cancer. Behavioural, viral and host factors modulate the risk of HPV persistence. In this thesis, I explore the role of the vaginal microbiota, a host factor and the presence of multiple HPV infections, a viral factor in HPV persistence. Considering the limited data on the epidemiology of HPV related diseases in low and middle-countries (LMIC), and the limited success of cervical cancer screening strategies in many LMIC, I provide data on the distribution of HPV related diseases in Nigeria and evaluate the acceptability of innovative strategies to increase cervical cancer screening uptake. Methods/Results: To achieve my aims, I implemented a longitudinal cohort study of 1,020 women in Nigeria. I begin my results chapters with two methodological papers. Attrition is an important consideration for every longitudinal cohort, particularly in LMIC, therefore, I present my findings on attrition, determinants of attrition and practical strategies to ensure low attrition in studies conducted in LMIC. Considering that sexual behaviour is an important potential confounder in all HPV studies, and the reliability of self-reported history is often questioned, I present findings on the test-retest reliability of self-reported sexual behaviour history collected in my study. Having found that attrition levels were low and that self-reported sexual behaviour history was generally reliable within my cohort, I present my findings on the association between the vaginal microbiota and persistent hrHPV; and the role of multiple HPV infections in viral persistence. I found that the vaginal microbiota was associated with persistent hrHPV in HIV negative women, but not in HIV positive women; and that multiple HPV infections did not increase the risk of viral persistence when compared to single HPV infections. Next, I present my findings on the prevalence and incidence of anogenital warts in Nigeria, with additional reports on the prevalence of cervical cancer and other HPV associated cancers using data from two population based cancer registries. Finally, I present my findings on the acceptability of innovative strategies to improve cervical cancer screening uptake in Nigeria. I found that Nigerian women had a favorable attitude to the use of HPV DNA based screening as part of routine antenatal care, however attitudes towards the use of self-sampling techniques for HPV based cervical cancer screening varied by religious affiliations. Conclusion: In my thesis, I was able to systematically investigate the epidemiology of HPV infections in a LMIC. I considered the distribution of HPV related diseases, host and viral determinants of HPV persistence and investigated control strategies to reduce the burden of cervical cancer in a LMIC. My results provide useful data for surveillance, monitoring and evaluation of control programs on HPV and cervical cancer in Nigeria and may be useful to cervical cancer control programs in other LMIC.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:763673 |
| Date | January 2018 |
| Creators | Dareng, Eileen Onyeche |
| Contributors | Pharoah, Paul |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.repository.cam.ac.uk/handle/1810/284551 |
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