BackgroundCervical cancer is the most common cancer among women of reproductive age in Thailand. However, information on the prevalence and correlates of anogenital HPV infection in Thailand is sparse.MethodsHPV genotype information, reproductive factors, sexual behavior, other STI and clinical information, and cervical cytology and histology were assessed at enrollment among one thousand two hundred and fifty-six (n = 1,256) HIV negative women aged 20–37 from Thailand enrolled in a prospective study of the natural history of HPV. The type-specific prevalence of HPV was estimated using cervical swab specimens from healthy women and women with a diagnosis of CIN 2/3 at baseline. Prevalence ratios (95% CI) were estimated using Poisson regression to quantify the association of demographic, behavioral, and clinical correlates with prevalent HPV infection.ResultsOverall, 307 (24.6%) and 175 (14.0%) of women were positive for any HPV type and any HR-HPV type, respectively; the most common types were 72, 52, 62, and 16. Among women diagnosed with CIN 2/3 at enrollment (n = 11), the most prevalent HPV types were 52 and 16. In multivariate analysis, HPV prevalence at enrollment was higher among women with: long-term combined oral contraceptive use, a higher number of lifetime sexual partners, a prior Chlamydia infection, and a current diagnosis of Bacterial Vaginosis.ConclusionThe study findings provide important information that can be used in the evaluation of primary and secondary interventions designed to reduce the burden of cervical cancer in Thailand.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-0886-z) contains supplementary material, which is available to authorized users.

Women diagnosed with cervical cancer report longer duration and more recent use of combined oral contraceptives (COCs). It is unclear whether COC use is associated with upstream events of human papillomavirus (HPV) infection prior to development of clinical disease. The objective of our study was to assess the association of contraceptive use on the risk for prevalent HPV infection in a cohort of long-term hormonal contraceptive (HC) users. One thousand and seventy (n 5 1,070) HIV-negative women aged 20-37 from Thailand enrolled in a prospective study of the natural history of HPV. Baseline HPV genotype information, recency and duration of HC use, sexual behavior, other sexually transmitted infection (STI) information and cervical cytology and histology were assessed. At enrollment, 19.8% and 11.5% of women were infected with any HPV or any high-risk (HR)-HPV, respectively. After adjustment for age, current and past sexual risk behaviors, STI history and cytology, the use of COCs for >6 years was found to be associated with an increased risk of infection with any HPV [prevalence ratio (PR): 1.88 (1.21, 2.90)] and any HR-HPV [PR: 2.68 (1.47, 4.88)] as compared to never users. Recent, long-term COC use was associated with an increased risk for prevalent HPV infection independent of sexual behavior and cervical abnormalities. No similar association was observed for recent or long duration use of progestin-only contraceptives (i.e., depomedroxyprogesterone acetate). These data suggest that COC use may impact early upstream events in the natural history of HPV infection.Cervical cancer is the second most common cancer among women worldwide and a leading cause of cancer-related mortality in the developing world.1 Genital human papillomavirus (HPV) infections have been identified as a necessary cause of cervical cancer.2-4 More than 35 different types of HPVs infect the genital tract, with $18 types considered oncogenic or potentially oncogenic. 5,6 Roughly 291 million women worldwide are currently infected with one of these anogenital HPVs, and approximately 80% of women will be exposed at some point in their lifetime, making HPV the most common sexually transmitted infection (STI).7 However, a majority of HPV infections spontaneously resolve within 1-2 years postdetection. Therefore, other environmental, host and viral cofactors are likely required for the development of cervical cancer. Long-term use of combined oral contraceptives (COCs) has been shown in several case-control studies to be associated with cervical cancer diagnosis among HPV-positive women.9-12 However, it is unclear whether this association is driven by COCs' effect on carcinogenesis or on upstream subclinical endpoints of the natural history such as HPV acquisition and persistence as prospective studies assessing these relationships are inconsistent.

Objective To evaluate the effect of depot medroxyprogesterone acetate (DMPA) in protecting against epithelial ovarian cancer (EOC) and to evaluate factors associated with the risk of EOC.Design A multicentre, case-control study.Setting Twelve hospitals located across Thailand.Population Three hundred and thirty patients with EOC ('cases') and 982 matched controls were recruited from the 12 hospitals. Cases were newly diagnosed patients with EOC, demonstrated pathologically. Controls were age-matched patients admitted to different wards in the same hospital.Methods Cases and controls were interviewed by trained interviewers using a standardised pre-tested questionnaire. The factors associated with EOC were evaluated using univariate and multivariate analyses.Main outcome measures The odds ratio (OR) and 95% confidence interval (95% CI) were calculated to assess the relationship between DMPA and EOC.Results The use of DMPA was found to be associated with a 39% reduction in the risk of EOC with an OR of 0.61 and a 95% CI of 0.44-0.85 (P = 0.002). A significant risk reduction (83%) was observed when the duration of DMPA use was >3 years (OR 0.17; 95% CI 0.07-0.39; P < 0.001). Other factors associated with a reduced risk of EOC were the use of combined oral contraceptive pills and breastfeeding. A factor associated with an increased risk of EOC was a family history of gynaecological cancer. ConclusionsThe results suggest that DMPA may have a protective effect against EOC. If this effect is real, then it represents an important non-contraceptive benefit of DMPA.

These data do not support the hypothesis that contraceptive use is associated with cervical cancer risk via increased risk of HPV acquisition. The increased risk of HPV persistence observed among current COC users suggests a possible influence of female sex hormones on host response to HPV infection.

Objectives