Although genital human papilloma virus (HPV) infection is the most commonly diagnosed sexually transmitted infection among young sexually active populations worldwide, no epidemiological studies of anogenital HPV infection have been conducted in Puerto Rico. Given that infection with certain types of HPV has been associated with cancer of the anus and cervix, information on the distribution of HPV types at anogenital sites is essential for the design, implementation and evaluation of vaccine studies and programs. Given the lack of available data for Puerto Rico, this study aims to determine the prevalence of cervical, anal and concurrent cervical/anal HPV infection and factors associated to HPV anogenital infection among a population-based sample of 600 women aged 18 to 64 years living in the San Juan, Metropolitan area of Puerto Rico, using a self-sampling collection methodology previously tested in a clinic-based sample population. In addition, we aim to determine the concordance of HPV types in the anus and cervix among infected women and to explore the frequency distribution of HPV variants among women with concurrent infection with HPV types 16, 18 and 31. A face-to-face interview and a computer-assisted self-interview (Audio CASI system) will collect information on risk factors for HPV infection including demographic characteristics and lifestyles. Anal and cervical specimens will be collected using Dracon swabs, which will be placed in separate 5-mL vials containing 1 mL Qiagen Specimen Sample Transport Medium (Qiagen Corp.) after collection. HPV DNA testing will be performed at the University of California, San Francisco, using a modified pool of MY09/MY11 consensus HPV L1 primers as well as primers for amplification of the human beta-globin gene. PCR products from positive samples will be typed by dot-blot hybridization using 39 individual type-specific probes. Strain variant typing from the E6 region will also be done. HPV-DNA prevalence will be calculated by HPV-type and all types combined. Crude and covariate adjusted Prevalence Odds will be estimated by logistic regression models. Three different logistic regression models will be constructed to evaluate factors associated with the following infection status: 1) anus HPV+/cervix HPV- , 2) anus HPV-/cervix HPV+, and 3) anus HPV+/cervix HPV+. On each of these models, women negative for both anal and cervical HPV infection (anal HPV-/ cervix HPV-) will be used as the reference group. Concordance of HPV-type among HPV infected individuals will be assessed by the kappa statistic and the concordance rate. This study will provide insights on the epidemiology of anogenital HPV infection and it will explore the distribution of HPV 16, 18 and 31 variants in this population in Puerto Rican women. This information is relevant to identify groups of population at risk for HPV infection and related anogenital cancers and to assess the impact of HPV vaccine programs.
The proposed study will be the first to estimate the prevalence of anogenital and concurrent (anus and cervix) HPV infection, to describe the distribution of HPV types, and to assess factors associated with HPV anogenital infection in a population-based sample of Puerto Rican women. In addition we will explore the distribution of HPV 16, 18 and 31 variants in this population. To our knowledge, this will be the first study to assess anal infection among a homogenous Hispanic population in the U.S. This study will provide insights on the epidemiology of HPV infection and of the relationship between anal and cervical HPV infection in this population, information that will contribute to the development of future studies of the etiology and transmission dynamics of HPV infection in Puerto Rico. Further, it will allow us to explore the burden of HPV types currently included (6, 11, 16 and 18) and not included in the available vaccines. These assessments are necessary to understand the burden of HPV in this population, to identify groups at risk for HPV infection, cervical cancer and other HPV related malignancies, and to determine the impact of vaccine programs. Information on the distribution of HPV types at anogenital sites will also guide the development of effective primary and secondary prevention interventions to reduce the burden of HPV infection and anogenital cancers among the Puerto Rican population and will aid in the design and implementation of future HPV vaccines and vaccine studies in the island.
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