Sexual Behaviour and HPV Infections in 18 to 29 Year Old Women in the Pre-Vaccine Era in the Netherlands

Contains fulltext : 71058.pdf ( ) (Open Access)BACKGROUND: Infection with Human Papillomavirus (HPV) is a necessary event in the multi-step process of cervical carcinogenesis. Little is known about the natural history of HPV infection among unscreened young adults. As prophylactic vaccines are being developed to prevent specifically HPV 16 and 18 infections, shifts in prevalence in the post vaccine era may be expected. This study provides a unique opportunity to gather baseline data before changes by nationwide vaccination occur. METHODS AND PRINCIPAL FINDINGS: This cross-sectional study is part of a large prospective epidemiologic study performed among 2065 unscreened women aged 18 to 29 years. Women returned a self-collected cervico-vaginal specimen and filled out a questionnaire. All HPV DNA-positive samples (by SPF(10) DEIA) were genotyped using the INNO-LiPA HPV genotyping assay. HPV point prevalence in this sample was 19%. Low and high risk HPV prevalence was 9.1% and 11.8%, respectively. A single HPV-type was detected in 14.9% of all women, while multiple types were found in 4.1%. HPV-types 16 (2.8%) and 18 (1.4%) were found concomitantly in only 3 women (0.1%). There was an increase in HPV prevalence till 22 years. Multivariate analysis showed that number of lifetime sexual partners was the most powerful predictor of HPV positivity, followed by type of relationship, frequency of sexual contact, age, and number of sexual partners over the past 6 months. CONCLUSIONS AND SIGNIFICANCE: This study shows that factors independently associated with HPV prevalence are mainly related to sexual behaviour. Combination of these results with the relative low prevalence of HPV 16 and/or 18 may be promising for expanding the future target group for catch up vaccination. Furthermore, these results provide a basis for research on possible future shifts in HPV genotype prevalence, and enable a better estimate of the effect of HPV 16-18 vaccination on cervical cancer incidence

A. Prevalence High-Risk HPV Types.

<p>Most common types detected were HPV type 16 (2.8%, n = 57), HPV type 51 (2.5%, n = 51), and HPV type 52 (2.5%, n = 52). In some women both low-risk and high-risk types were detected. B. Prevalence Low-Risk HPV Types. In some women both low-risk and high-risk types were detected. HPV genotype 53 and 66 can also be considered as possible high risk types.</p

HPV prevalence and Odds Ratio's for HPV prevalence among sexually active women using univariate analysis and logistic regression.

<p>HPV+ if one or more genotypes are detected simultaneously.</p><p>Sample sizes change because of missing values of the questionnaire.</p><p>n = number.</p><p>95% C.I. Confidence Interval.</p><p>p: p-value.</p>∧<p>Mann Whitney.</p>*<p>by Chi-square test.</p><p>Ref: reference.</p><p>OCC oral contraceptives.</p>¤<p>Living apart together.</p>**<p>below the age of 10 years several cases of sexual abuse were reported.</p>°<p>STI, Sexually Transmitted Infection.</p>□<p>Sexual age in years with 0 and 1 combined as well as sexual age higher than 13.</p

A. Prevalence of Low-Risk and High-Risk Types by Age (n = 2065).

<p>Prevalence of overall and both hr- and lr-HPV types showed an almost similar age-distribution. In some women both low-risk and high-risk types were detected. B. Prevalence of Low-Risk and High-Risk Types by Sexual Age (n = 1943). Only sexually active women were selected (n = 1943). Overall HPV prevalence, as well as hr- and lr-HPV prevalence, showed an increase with rising sexual age. However, hr-HPV prevalence decreased from a sexual age of 10 years. In some women both low-risk and high-risk types were detected.</p

HPV prevalence by demographic variables among all women.

<p>HPV+ if one or more genotypes(high risk as well as low risk) are detected simultaneously.</p><p>Sample sizes change because of missing values of the questionnaire.</p><p>n = number.</p><p>- not applicable.</p>*<p>by Chi-square test.</p>○<p>ethnicity was self-reported.</p>∧<p>type of education: group of lower secondary education includes 2 women who reported only primary/no education.</p>¤<p>Living apart together.</p><p>OCC oral contraceptives.</p

Adjusted Odds Ratio's for HPV prevalence among sexually active women using multivariate logistic regression (n = 1820).

<p>n = number.</p><p>95% C.I. Confidence Interval.</p><p>p: p-value.</p>¤<p>Living apart together.</p><p>Ref: reference.</p>°<p>STI, Sexually Transmitted Infection.</p>□<p>Sexual age in years with 0 and 1 combined as well as sexual age higher than 13.</p

95% Confidence Interval of HPV Prevalence by Age (n = 2065).

<p>There was an overall increase in HPV prevalence with age till 22 years, afterwards a plateau phase was reached. A decrease is shown at 23 years and a peak among women aged 27 years, however, as the 95% confidence interval is overlapping with adjacent age groups, the differences were considered accidental findings.</p