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Robert D Burk

Publications and source records attributed to Robert D Burk.

At least 19 recordsLinked to original sources
PubMed2026

Longitudinal analysis of high-risk HPV infections reveals within-host viral genome changes over time.

Persistent infection with high-risk (HR)-HPV causes cervical cancer, however, it is unclear why most infections resolve while a minority progress. We deep sequenced the HPV genomes of 1,228 HR-HPV-positive serial samples from 351 women with persistent infections (2-10 serial samples per woman over 1-8 years), including 279 controls and 72 precancer/cancer cases, to assess HR-HPV genome changes during infection and relation to infection outcomes. Seventy-seven percent of persistent infections (45-97% by HPV type) were infections with the same exact viral genome isolate; for HPV16, only 52% were persistent with the same isolate. This may suggest some infections include a type-specific isolate switch or new isolate infection during persistence. We additionally observed within-host change to the HPV genome estimated as gradual changes to intrahost single nucleotide variant (iSNV) frequency, and changes varied by HPV type, with HPV33 infections showing the most iSNV changes. Cases exhibited fewer viral genome changes during infection compared to controls (OR = 0.31, 95% CI = 0.1 - 0.86, p = 0.019), suggesting a more stable and clonal viral genome in cases. By viral gene, E7 had fewer nonsynonymous mutations in the cases compared to controls that cleared within 2 years of infection (p = 0.012), which confirms the importance of E7 conservation and suggests mutations to E7 reduce persistence associated with progression. There was a similar pattern in E4 (p = 0.013), while E5 had more changes in the cases (p = 0.008). A subset of 28 infections had an intervening HPV-negative sample between HPV-positive visits; 93% of these infections had the same exact viral genome isolate in the samples before and after the negative, consistent with subclinical persistence and subsequent re-detection. Our data suggests that HR-HPV type-persistence can include a collection of viral isolates, and viral mutations during infection, particularly in E7, reduce HR-HPV persistence and thus carcinogenic potential.

Humans↗
PubMed2007

Combined human papillomavirus DNA and human papillomavirus-like particle serologic assay to identify women at risk for high-grade cervical intraepithelial neoplasia.

The objective of this study was to assess the utility of a second generation human papillomavirus (HPV) virus-like particle (VLP)-based ELISA as an adjunct to HPV DNA testing to identify women at risk for high-grade cervical intraepithelial neoplasia (CIN). Participants provided blood, cervical samples and interviewer-obtained questionnaire information. HPV VLPs for types 16, 18, 33, 45 and 52 were produced using a baculovirus expression system. These highly purified VLPs were used in a polymer-based ELISA test. Cases with biopsy-confirmed CIN (CIN I, n = 237; CIN II, n = 56; CIN III, n = 48) and controls (n = 351) with normal Pap smears were tested for HPV DNA by PCR and serologic response to multiple oncogenic HPV VLPs. 258/341 (76%) of cases and 230/351 (65.5%) of control patients had any type of HPV VLP antibody (OR = 1.63, 95% CI 1.16-2.30). More cases were seropositive than controls for each individual HPV type (p < 0.001 for HPV types 16, 18, 33 and 45; p = 0.06 for HPV 52). Reactivity to an increasing number of different HPV type-specific VLPs are associated with high-grade CIN independent of HPV DNA status. HPV VLP assays may be useful as an adjunct to HPV DNA testing in a subset of patients that needs to be defined by further studies.

Adult↗
PubMed2006

Development of a non-denaturing electrophoresis system for characterization of neutralizing epitopes on HPV virus-like particles.

The precise structure of the HPV16 major neutralizing epitope recognized by H16.V5 monoclonal antibody is unknown. This paper describes a novel polyacrylamide gel electrophoresis (PAGE) for separation of HPV virus-like particles (VLPs) using cetyltrimethylammonium chloride (CTAC) as a solubilizing agent. CTAC PAGE employs KOH/CH3CO2H (pH 4-5.4) as a buffer system, K+ as the leading ion and 3-aminopropionic acid as a trailing ion. The unique characteristics of a cationic electrophoresis system allow separation of VLPs without heat denaturation. HPV VLP gel migration patterns were dependent on pre-treatment conditions: (1) thiol-agent reduction alone resulted in a 174 kDa band (interpreted as a L1 trimer), a 53 kDa band (size of the L1 monomer), as well as higher Mr aggregates consistent with a pentamer size; (2) both heat denaturation and thiol-agent reduction resulted in a 53 kDa band. Western blot analysis showed that the 174 kDa L1 trimer was strongly immunoreactive with H16.V5 and HPV16 VLP ELISA positive human sera, whereas no reactivity was seen with the monomeric L1 unit. These data suggest that a structure consistent with the migration pattern of a L1 trimer contains the major neutralizing epitope recognized by the H16.V5 MAb and human sera.

Antibodies, Viral↗
PubMed2006

Human papillomavirus (HPV) types 101 and 103 isolated from cervicovaginal cells lack an E6 open reading frame (ORF) and are related to gamma-papillomaviruses.

Complete genomes of HPV101 and HPV103 were PCR amplified and cloned from cervicovaginal cells of a 34-year-old female with cervical intraepithelial neoplasia grade 3 (CIN 3) and a 30-year-old female with a normal Pap test, respectively. HPV101 and HPV103 contain 4 early genes (E7, E1, E2, and E4) and 2 late genes (L2 and L1), but both lack the canonical E6 ORF. Pairwise alignment similarity of the L1 ORF nucleotide sequences of HPV101 and HPV103 indicated that they are at least 30% dissimilar to each other and all known PVs. However, similarities of the other ORFs (E7, E1, E2, and L2) indicated that HPV101 and HPV103 are most related to each other. Phylogenetic analyses revealed that these two types form a monophyletic clade, clustering together with the gamma- and pi-PV groups. These data demonstrated that HPV genomes closely related to papillomaviruses identified from cutaneous epithelia can be isolated from the genital mucosal region. Moreover, this is the first report of HPVs lacking an E6 ORF and phylogenetic evidence suggests this occurred subsequent to their emergence from the gamma-/pi-PVs.

Adult↗
PubMed2006

Persistent human papillomavirus infection is associated with a generalized decrease in immune responsiveness in older women.

The development of cervical cancer and its precursors are linked to persistent infection with oncogenic types of human papillomavirus (HPV). Host immune responses seem to be determinants of risk for this disease. However, little is known about the immunologic determinants of HPV persistence. Here, we examined the association between lymphoproliferative responses to antigens/mitogens and persistent HPV infection in women older than 45 years. Women included in this study were participants in a 10,000-woman population-based cohort study of cervical neoplasia in Costa Rica. Women older than 45 years and HPV DNA positive at a screening visit were selected as cases (n = 283). We selected a comparably sized control group of HPV DNA-negative women, matched to cases on age and time since enrollment (n = 261). At an additional clinical visit, women were cytologically and virologically rescreened, and cervical and blood specimens were collected. Proliferative responses to phytohemagglutinin (PHA), influenza virus (Flu), and HPV16 virus-like particle (VLP) were lower among women with persistent HPV infection [median counts per minute (cpm): 72,849 for PHA, 1,241 for Flu, and 727 for VLP] than for the control group (median cpm: 107,049 for PHA, 2,111 for Flu, and 2,068 for VLP). The decreases were most profound in women with long-term persistence and were only observed for the oldest age group (>/=65 years). Our results indicate that an impairment in host immunologic responses is associated to persistent HPV infection. The fact that effects were evident for all studied stimuli is suggestive of a generalized effect.

Age Factors↗
PubMed2006

Human papillomavirus prevalence in women who have and have not undergone hysterectomies.

We compared human papillomavirus (HPV) prevalence in an age-stratified random sample of women who have undergone a hysterectomy (WH) (n=573) with the HPV prevalence in age-matched women with intact cervices (women who have not undergone a hysterectomy [WNH]) (n=581) participating in a study at Kaiser Permanente in Portland, Oregon. Testing cervicovaginal lavage fluids for >40 HPV genotypes using an MY09/11 L1 consensus primer polymerase chain reaction method, we found no statistical differences in the prevalence of HPV (16% for WNH vs. 13.9% for WH) or carcinogenic HPV (6.5% for WNH vs. 4.5% for WH) between the 2 groups of women. Although WH have a similar prevalence of carcinogenic HPV infection, compared with WNH without a cervix, they have minimal risk of HPV-induced cancer and are unlikely to benefit from HPV testing.

Adult↗
PubMed2006

Relationships of human papillomavirus type, qualitative viral load, and age with cytologic abnormality.

Persistent cervical infections with carcinogenic human papillomaviruses (HPV) cause virtually all cervical cancer. Cytologic abnormalities are the manifestations of HPV infections used to identify women at risk. To compare the potential of the full range of anogenital HPV genotypes to induce cytopathic effects, we examined the influences of HPV type, viral load, and age on cytopathology among 1,222 women having a single HPV type at enrollment into a 10,000-woman population-based study in Costa Rica. Cervical specimens were tested for approximately 40 HPV types by MY09/MY11 L1 primer PCR and type-specific dot blot hybridization. Types were organized by phylogenetic species and cancer risk. PCR signal strength served as a qualitative surrogate for viral load. Overall, 24.8% [95% confidence interval (95% CI), 22.4-27.3] of single prevalent HPV infections had concurrent abnormalities (atypical squamous cells or worse) ranging from 0.0% to 80.0% based on HPV type. Noncarcinogenic alpha3/alpha15 types, although highly prevalent, uncommonly caused cytologic abnormalities (13.1%; 95% CI, 9.8-17.0). In contrast, one quarter to nearly one half of infections with a single major carcinogenic species type (alpha9/alpha11/alpha7/alpha5/alpha6) produced abnormalities. Greater abnormalities were observed with increasing qualitative viral load of carcinogenic types; fewer abnormalities were observed among older women (>54 years). A high percentage (46.2%) of detected abnormalities in women infected with HPV16 or related alpha9 types were high grade or worse, consistent with strong carcinogenicity, compared with 10.7% in women infected with alpha7 types, including HPV18, a major cause of adenocarcinoma. The lack of evident severe abnormalities associated with HPV18 and related HPV types might have implications for screening for poorly detected glandular and alpha7-related lesions.

Adult↗
PubMed2006

Primary cilium formation requires von hippel-lindau gene function in renal-derived cells.

Biallelic inactivation of the von Hippel-Lindau tumor suppressor gene, VHL, occurs in the majority of renal clear cell carcinomas (RCC). VHL's function, regulating the degradation of hypoxia-inducible factor alpha (HIFalpha) subunits, explains the angiogenic nature of these tumors, but not tumor initiation. Because the development of renal cysts precedes tumor formation, and because the dysfunction of primary cilium is a common pathogenic mechanism in polycystic kidney diseases, we determined whether kidney-derived VHL- cells required VHL for the generation of cilium. Ectopic expression of VHL in RCC(VHL-) cells induced increased polarization and primary cilium formation. Cilium formation correlated directly with the expression of both wild-type VHL isoforms and a VHL mutant not associated with RCC development, whereas expression of RCC-associated VHL mutants did not support ciliogenesis. Requirement of VHL for ciliogenesis was independent of HIFalpha abundance. These data indicate separable independent functions for VHL (HIFalpha degradation and differentiation) and suggest a mechanism whereby disruption of both functions is required for renal carcinogenesis.

Adenocarcinoma, Clear Cell↗
PubMed2006

Incidence of and risk factors for genital human papillomavirus infection in women drug users.

A total of 230 women drug users were prospectively studied. At 6-month intervals, interviews, HIV testing, and cervicovaginal lavage sampling for human papillomavirus (HPV) were performed. HPV was detected and typed using a MY09/MY11 polymerase chain reaction system. 230 women without high-risk HPV (types 16, 18, 26, 31, 33, 35, 39, 45, 51, 52, 56, 58. 59, 68, 73 and 82), with or without non-high risk HPV types at baseline, were included in analyses. Incidence rates of and factors associated with HPV infections of all types and high-risk types (types 16, 18, 26, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73, and 82) were analyzed. Baseline median age was 40 years (range 24-65); 62% of women were Hispanic, 20% black, and 16% white; 54 (24%) were HIV seropositive; 172 (75%) were without detectable HPV; 58 (25%) had only low-risk or untypeable HPV. The incidence rates for any and for high-risk type HPV infection were 9.5/100 and 4.8/100 person-years, respectively. HIV-positive women had a significantly increased hazard rate for any HPV (HRadj: 3.4; 95% CI: 1.4 to 8.0) and for high-risk HPV (HRadj 3.0; 95% CI: 1.4 to 6.6), adjusted for race, sexual behaviors, condom use, and history of other sexually transmitted infections. HIV infection was independently associated with a substantial and significantly increased risk for any and for high-risk genital HPV infection and was the most important risk factor found.

Adult↗
PubMed2006

Age-related changes of the cervix influence human papillomavirus type distribution.

Approximately 15 human papillomavirus (HPV) types cause virtually all cervical cancer whereas other HPV types are unrelated to cancer. We were interested in whether some noncarcinogenic types differ from carcinogenic in their affinity for the cervical transformation zone, where nearly all HPV-induced cancers occur. To examine this possibility, we tested cervical specimens from 8,374 women without cervical precancer and cancer participating in a population-based study in Guanacaste for >40 HPV types using PCR. We compared age-group specific prevalences of HPV types of the alpha9 species, which are mainly carcinogenic and include HPV16, to the genetically distinct types of the alpha3/alpha15 species (e.g., HPV71), which are noncarcinogenic and common in vaginal specimens from hysterectomized women. We related HPV detection of each group to the location of the junction between the squamous epithelium of the ectocervix and vagina and the columnar epithelium of the endocervical canal. Models evaluated the independent effects of amount of exposed columnar epithelium (ectopy) and age on the presence of alpha9 or alpha3/alpha15 types. Prevalence of alpha9 types (7.6%) peaked in the youngest women, declined in middle-aged women, and then increased slightly in older women. By contrast, prevalence of alpha3/alpha15 types (7.6%) tended to remain invariant or to increase with increasing age. Detection of alpha9 infections increased (P(trend) < 0.0005) but alpha3/alpha15 infections decreased (P(trend) < 0.0005) with increasing exposure of the columnar epithelia. Older age and decreasing cervical ectopy were independently positively associated with having an alpha3/alpha15 infection compared with having an alpha9 infection. These patterns need to be confirmed in other studies and populations. We suggest that these genetically distinct groups of HPV types may differ in tissue preferences, which may contribute to their differences in carcinogenic potential.

Adult↗
PubMed2006

Stage of change behavioral assessment tool fails to predict the prevalence of chlamydia in an urban adolescent health clinic.

STUDY OBJECTIVE: Strategies to reduce STI among adolescents and young adults have failed to consistently demonstrate effectiveness. A universal approach may not be appropriate because individuals are at different stages with respect to self-management behaviors. Thus, the Stage of Change Transtheoretical Model has been advocated. This study was conducted to determine whether staging could be accomplished in an urban adolescent clinic and whether it provides a tool to predict STI risk. DESIGN: Participants were interviewed and staged according to a standardized instrument with respect to sexual risk behaviors and contraceptive use. SETTING: Urban adolescent health clinic. PARTICIPANTS: 103 females (ages 18-24). INTERVENTIONS: A physical examination and diagnostic tests for syphilis, HSV, HCV, chlamydia, gonorrhea and HPV were performed. MAIN OUTCOME MEASURES: Stages for behaviors to reduce STI risk and to utilize contraception and STI prevalence. RESULTS: 78% of the participants were in the three earliest stages of behavior (precontemplative, contemplative, and ready for action) with respect to condom use for STI prevention; conversely only 47% were in early stages with respect to birth control practices. Of the participants tested, 12/81 (15%) had chlamydial infection detected by molecular techniques, whereas no participants had gonorrhoeae. Among the subset tested for HPV DNA, 18/45 (40%) were positive. The diagnostic behavior stage for STI prevention did not correlate with the presence of chlamydia. CONCLUSIONS: A staging instrument can be implemented into adolescent health clinic practice, but cannot be used as a risk assessment tool for the presence of chlamydia. Additionally females are more likely to protect themselves against pregnancy than against an STI.

Adolescent↗
PubMed2006

Serological detection of human papillomavirus type 16 infection in human immunodeficiency virus (HIV)-positive and high-risk HIV-negative women.

Serial measurement of antibodies has not been used to provide evidence of active viral replication of human papillomavirus (HPV). Serum specimens from sequential study visits contributed by 642 human immunodeficiency virus (HIV)-positive and 116 HIV-negative participants enrolled in the Women's Interagency HIV Study were used to detect significant rises in HPV type 16 (HPV-16) antibody levels. Factors associated with a significant rise were identified using multivariable logistic regression models with generalized estimating equations. Among HIV-positive women, 8.3% of 1,997 pairs showed antibody rises, compared to 6.1% of 361 pairs among HIV-negative women (P = 0.191). For HIV-positive women, rises were associated with current (odds ratio [OR], 23.4; P < 0.001) or past (OR, 8.9; P < 0.001) HPV-16 infection relative to never being HPV-16 infected and with CD4+ cell counts (OR per 100-cell increase, 0.8; P < 0.001) but not with sexual behavior. For HIV-negative women, rises were associated with past (OR, 10.9; P = 0.033) HPV-16 infection relative to no HPV-16, current cigarette smoking (OR, 5.0; P = 0.029) relative to no smoking history, and having 6 to 10 lifetime sexual partners compared to 0 to 5 partners (OR, 9.9; P = 0.036). Serial measurement of HPV-16 serum antibodies is a useful tool for identifying active HPV-16 viral replication. Rises among HIV-positive women may more often result from reactivation of a latent HPV infection in the context of HIV-induced immunosuppression, while rises among HIV-negative women may more often result from reinfection with HPV.

Antibodies, Viral↗
PubMed2006

Inflammation, genetic polymorphisms in proinflammatory genes TNF-A, RANTES, and CCR5, and risk of pancreatic adenocarcinoma.

Adenocarcinoma of the exocrine pancreas is the fourth leading cause of cancer-related death in men and women in the U.S. Cytokines and other proinflammatory mediators have been implicated in inflammatory pancreatic diseases including pancreatitis and cancer. We analyzed cytokine gene polymorphisms as risk factors for pancreatic cancer using questionnaire data obtained by in-person interviews and germ line DNA collected in a population-based case-control study of pancreatic cancer (532 cases and 1,701 controls) conducted in the San Francisco Bay Area. We used mass spectrometry and gel-based methods to genotype 308 cases and 964 population-based controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression analysis and included adjustment for age, sex, and smoking. We assessed potential interactions between these polymorphisms, proinflammatory conditions (e.g., pancreatitis, ulcer, and obesity), and smoking as risk factors for pancreatic cancer. There was no overall association between pancreatic cancer risk and tumor necrosis factor-alpha (TNF-A -308G/A), regulated upon activation, normally T cell-expressed, and presumably secreted (RANTES -403G/A), and CC chemokine receptor 5 (CCR5-Delta32) polymorphisms. There was a nearly 7-fold increased relative risk estimate for pancreatic cancer in individuals with a history of pancreatitis (adjusted OR, 6.9; 95% CI, 3.4-14.1). Among patients with pancreatic cancer, pancreatitis was significantly associated with TNF-A -308 GA + AA (OR, 3.1; 95% CI, 1.3-7.4) and with RANTES -403 GA + AA (OR, 2.3; 95% CI, 1.0-5.4). There was evidence for a possible interaction between current active smoking and CCR5-32del. Our results lend support for the hypothesis that proinflammatory gene polymorphisms, in combination with proinflammatory conditions, may influence the development of pancreatic cancer.

Adenocarcinoma↗
PubMed2005

Family history as a co-factor for adenocarcinoma and squamous cell carcinoma of the uterine cervix: results from two studies conducted in Costa Rica and the United States.

Previous work suggests that cervical cancer may aggregate in families. We evaluated the association between a family history of gynecological tumors and risk of squamous cell and adenocarcinomas of the cervix in 2 studies conducted in Costa Rica and the United States. The Costa Rican study consisted of 2,073 women (85 diagnosed with CIN3 or cancer, 55 diagnosed with CIN2 and 1,933 controls) selected from a population-based study of 10,049 women. The U.S. study consisted of 570 women (124 with in situ or invasive adenocarcinomas, 139 with in situ or invasive squamous cell carcinomas of the cervix and 307 community-based controls) recruited as part of a multicentric case-control study in the eastern part of the United States. Information on family history of cervical and other cancers among first-degree relatives was ascertained via questionnaire. Information on other risk factors for cervical cancer was obtained via questionnaire. Human papillomavirus (HPV) exposure was assessed in both studies using broad spectrum HPV L1-based PCR testing of exfoliated cervicovaginal cells and in Costa Rica by additional testing of plasma collected from participants for antibodies against the L1 protein of HPV types 16, 18, 31 and 45 by ELISA. A family history of cervical cancer in a first-degree relative was associated with increased risk of squamous tumors in both studies (odds ration [OR] = 3.2 for CIN3/cancer vs. controls; 95% confidence interval [CI] = 1.1-9.4 in Costa Rica; OR = 2.6 for in situ/invasive squamous cell carcinoma cases vs. controls, 95% CI = 1.1-6.4 in the Eastern United States study). These associations were evident regardless of whether the affected relative was a mother, sister or daughter of the study participant. Furthermore, observed effects were not strongly modified by age. In Costa Rica, the effect persisted in analysis restricted to HPV-exposed individuals (OR = 3.0; 95% CI = 1.0-9.0), whereas in the Eastern United States study there was evidence of attenuation of risk in analysis of squamous carcinoma cases restricted to HPV positive women (OR = 1.4; 95% CI = 0.29-6.6). No significant association was observed between a family history of cervical cancer in a first-degree relative and adenocarcinomas (OR = 1.3; 95% CI = 0.43-3.9). History of gynecological tumors other than cervical cancer in a first-degree relative was not significantly associated with risk of disease in either study. These results are consistent with a role of host factors in the pathogenesis of squamous cell cervical cancer, although familial aggregation due to shared environmental exposures cannot be ruled out.

Adenocarcinoma↗
PubMed2005

The carcinogenicity of human papillomavirus types reflects viral evolution.

Persistent infections with carcinogenic human papillomaviruses (HPV) cause virtually all cervical cancers. Cervical HPV types (n > 40) also represent the most common sexually transmitted agents, and most infections clear in 1-2 years. The risks of persistence and neoplastic progression to cancer and its histologic precursor, cervical intraepithelial neoplasia grade 3 (CIN3), differ markedly by HPV type. To study type-specific HPV natural history, we conducted a 10,000-woman, population-based prospective study of HPV infections and CIN3/cancer in Guanacaste, Costa Rica. By studying large numbers of women, we wished to separate viral persistence from neoplastic progression. We observed a strong concordance of newly-revised HPV evolutionary groupings with the separate risks of persistence and progression to CIN3/cancer. HPV16 was uniquely likely both to persist and to cause neoplastic progression when it persisted, making it a remarkably powerful human carcinogen that merits separate clinical consideration. Specifically, 19.9% of HPV16-infected women were diagnosed with CIN3/cancer at enrollment or during the five-year follow-up. Other carcinogenic types, many related to HPV16, were not particularly persistent but could cause neoplastic progression, at lower rates than HPV16, if they did persist. Some low-risk types were persistent but, nevertheless, virtually never caused CIN3. Therefore, carcinogenicity is not strictly a function of persistence. Separately, we noted that the carcinogenic HPV types code for an E5 protein, whereas most low-risk types either lack a definable homologous E5 ORF and/or a translation start codon for E5. These results present several clear clues and research directions in our ongoing efforts to understand HPV carcinogenesis.

Cocarcinogenesis↗
PubMed2005

A prospective study of age trends in cervical human papillomavirus acquisition and persistence in Guanacaste, Costa Rica.

BACKGROUND: Cross-sectional human papillomavirus (HPV) DNA prevalence peaks at young ages, reflecting sexual acquisition and typically rapid clearance. In some populations, HPV prevalence demonstrates a second peak in older women. Longitudinal data may help to explain this second peak. METHODS: We followed a population-based cohort of 7237 women in Guanacaste, Costa Rica, in which we had previously observed a second peak in the baseline HPV prevalence in older women. We tested for >40 HPV types by polymerase chain reaction. We analyzed age-specific patterns of acquisition and persistence 5-7 years after enrollment for individual HPV types. RESULTS: At enrollment and follow-up, cross-sectional data revealed U-shaped age-specific HPV prevalence curves for virtually every type, with higher prevalences in the younger and older women than in the middle-aged women. Prospectively, acquisition of types decreased significantly as women aged (PTrend<.05, for both), with the highest peak in young women and a secondary minor peak in older women. Type-specific persistence of HPV increased with age (PTrend<.0001). Overall, HPV acquisition predominated at younger ages, whereas persistent infections gradually became more prominent with age (PTrend<.0001). CONCLUSIONS: Newly apparent infections decreased, whereas persistence increased, with age; this latter tendency supports the utility of HPV screening in older women.

Adult↗
PubMed2005

Epidemiologic profile of type-specific human papillomavirus infection and cervical neoplasia in Guanacaste, Costa Rica.

BACKGROUND: Detailed epidemiologic studies of cervical type-specific human papillomavirus (HPV) infection in large populations are scarce. METHODS: We recruited a population-based cohort in Guanacaste, Costa Rica. Participants were interviewed, screened for cervical neoplasia, and tested for >40 HPV types by use of MY09/11 L1 consensus primer polymerase chain reaction. We estimated the risk factors for infection and the associations between type-specific HPV infections and cervical intraepithelial neoplasia (CIN) and cancer in 8514 sexually active women who had not undergone a hysterectomy. RESULTS: The overall HPV prevalence was 26.5%. The most common type was HPV-16 (3.6% of the population). HPV prevalence showed a U-shaped age-specific curve. Sexual behaviors were the main determinants of oncogenic and nononcogenic infections; age at first sexual intercourse was not independently associated with infection. Barrier contraceptive use was somewhat protective against infection. Oncogenic infections were strongly associated with risk of all grades of CIN and of cancer. Types 16, 18, and 58 were the most common in women diagnosed with CIN3 and cancer. Except for those that included HPV-16, multiple-type infections were associated with an increased risk (compared with that for single-type infections) of all grades of CIN and of cancer. CONCLUSIONS: We confirmed the bimodal age pattern of HPV infection in Guanacaste and the sexually transmitted nature of both oncogenic and nononcogenic HPV types.

Adult↗