Introduction. Human papillomavirus (HPV) infection is now believed to be the central cause of cervical cancer. However, most of the epidemiological evidence has come from retrospective, case-control studies, which do not provide information on the dynamics of a cumulative or persistent HPV infection. / Objectives. (1) To measure the risk of incident neoplastic cervical lesions over time related to prior cumulative and persistent HPV infections. (2) To evaluate the influence of HPV viral burden on lesion risk longitudinally. (3) To estimate the progression rates and sojourn time for precursor squamous intraepithelial lesions (SILs) and how they relate to HPV infection status. / Design and methods. In 1993, the Ludwig-McGill study team began a large longitudinal study of the natural history of HPV infection and cervical neoplasia in the city of Sao Paulo, Brazil. Follow-up involved repeated measurements on individual subjects over time. 2462 women were enrolled into the study and were seen every 4 months in the first year (0, 4, 8 and 12 months), and twice yearly thereafter for a period of up to eight years. In addition to obtaining risk factor information via questionnaire, cervical specimens were taken for Pap cytology and HPV testing at every visit. Statistical analyses entailed: (1) using different modalities for defining HPV persistence by type and intensity; (2) using modeling approaches that take into account the repeated measurements of HPV and SIL over time within individuals; (3) analyzing changes in transition states between different cervical lesion grades and the rate of progression from one state to the next. / Rationale. A longitudinal, repeated measurement cohort investigation, such as this one, permits an accurate and unbiased assessment of the relationship between cumulative HPV exposure and lesion incidence. An elevated relationship between persistent HPV infections and SIL incidence supports the proposal for the application of type-specific molecular HPV DNA testing as a screening tool for the detection of cervical neoplasia. Better understanding of the natural history of disease can help in developing effective and efficient public health programs in prevention for cervical cancer.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.84431 |
| Date | January 2002 |
| Creators | Schlecht, Nicolas |
| Contributors | Franco, Eduardo L. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Epidemiology and Biostatistics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001973907, proquestno: AAINQ88575, Theses scanned by UMI/ProQuest. |
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