Sharp increase in gonorrhoea notifications among young people, EU/EEA, July 2022 to June 2023

Gonorrhoea cases increased steeply in women aged 20 to 24 years across 15 EU/EEA countries in July to December 2022 and January to June 2023 with, respectively, 73% and 89% more cases reported than expected, based on historical data from 2015 to 2019. Smaller increases among men due to heterosexual transmission were observed in nine EU/EEA countries. Interventions to raise awareness among young people about sexually transmitted infection risks are needed, emphasising the benefit of safe sexual practices and testing.

Improvement in Neisseria gonorrhoeae culture rates by bedside inoculation and incubation at a clinic for sexually transmitted infections

BACKGROUND

Culture of Neisseria gonorrhoeae is essential for surveillance of complete antimicrobial susceptibility profiles. In 2014, the culture success rate of N. gonorrhoeae from samples taken at the clinic for sexually transmitted infections (STI clinic), Oslo University Hospital, Norway, was only 20%. The present study aimed to improve gonococcal culture rates using bedside inoculation of patient samples on gonococcal agar plates and incubation at the STI clinic.

METHODS

This prospective quality improvement study was conducted by the STI clinic and the Department of Microbiology at Oslo University Hospital from May 2016 - October 2017. When culture of N. gonorrhoeae was clinically indicated, we introduced a parallel 'bedside culture' at the STI clinic and compared results with the standard culture at the microbiology department. Samples were taken from urethra, anorectum, pharynx and cervix. Culture rates were compared across symptomatic and asymptomatic anatomical sites.

RESULTS

From 596 gonococcal-positive PCR samples, bedside culture had a significantly higher success rate of 57% compared to 41% with standard culture (p < 0.05). Overall, culture rate from symptomatic sites was 91% v. 45% from asymptomatic sites. The culture rates from different anatomical sites were as follows: urethra 93%, anorectum 64%, pharynx 28% and cervix 70%. Bedside culture significantly (p < 0.05) improved the culture rates for symptomatic urethral and asymptomatic pharyngeal samples.

CONCLUSIONS

Where feasible, bedside inoculation on gonococcal agar plates and incubation of samples from patients with gonorrhoea is recommended. This will improve the culture diagnostics and provide additional gonococcal isolates for antimicrobial resistance surveillance.

Sexually transmitted infections among patients attending a sexual assault centre: a cohort study from Oslo, Norway

OBJECTIVES

We estimate the prevalence of sexually transmitted infection (STI) among patients after sexual assault, assess the possible value of azithromycin prophylaxis, and identify risk factors for assault-related STI and for not presenting at follow-up.

DESIGN

Prospective observational cohort study.

SETTING

Sexual assault centre in Oslo, Norway.

PARTICIPANTS

645 patients, 602 (93.3%) women and 43 (6.7%) men, attending the centre from May 2017 to July 2019.

OUTCOME MEASURES

Microbiological testing at the primary examination and at follow-up consultations after 2, 5 and 12 weeks. Estimated relative risk for assault-related STI and for not presenting at follow-up.

RESULTS

At primary examination, the prevalence of genital chlamydia was 8.4%, Mycoplasma genitalium 6.4% and gonorrhoea 0.6%. In addition, the prevalence of bacterial STI diagnosed at follow-up and possibly from the assault was 3.0% in total: 2.5% for M. genitalium, 1.4% for genital chlamydia and 0.2% for gonorrhoea. This prevalence did not change when azithromycin was no longer recommended from January 2018. There were no new cases of hepatitis B, hepatitis C, HIV or syphilis. We found no specific risk factors for assault-related STI. Patients with previous contact with child welfare service less often presented to follow-up (relative risk (RR) 2.0 (95% CI 1.1 to 3.5)), as did patients with a history of sex work (RR 3.6 (1.2 to 11.0)) or substance abuse (RR 1.7 (1.1 to 2.7)).

CONCLUSIONS

Most bacterial STIs were diagnosed at the primary examination, hence not influenced by prophylaxis. There was no increase in bacterial STI diagnosed at follow-up when azithromycin prophylaxis was not routinely recommended, supporting a strategy of starting treatment only when infection is diagnosed or when the patient is considered at high risk. Sex work, substance abuse and previous contact with child welfare services were associated with not presenting to follow-up.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03132389).

Genomic epidemiology and population structure of Neisseria gonorrhoeae in Norway, 2016-2017

This study presents the nationwide epidemiology of Neisseria gonorrhoeae, using whole-genome sequencing of all culture-positive cases, which comprise roughly 40 % of all cases of gonorrhea reported in Norway from 2016 to 2017. Isolates were assigned to sequence types and Bayesian analysis clusters and variation in genes coding for antibiotic resistance was linked to phenotypic resistance data. The study also included isolates taken from the same patients from different anatomical sites at one or more time points. Comparing these isolates allows for observation of patterns of infections, i.e. multiple reinfections of genetically related clones vs. reinfections of genetically distant clones, and quantification of the genomic variation of closely related isolates from samples taken from a patient within the same day. Demographically, the patients in the study could be split into two groups; one group of patients from the capital with a high proportion of men who have sex with men (MSM), and another consisting of young adults with transmission primarily between males and females from outside the capital. Some clusters of N. gonorrhoeae were restricted to one of these two demographic groups. Pairwise comparison of multiple isolates from the same patients revealed that most were reinfected with different clones. Observations of frequent reinfections in patients is a concern and should be taken into account in the development of improved information and treatment guidelines.

The impact of HPV multi-cohort vaccination: Real-world evidence of faster control of HPV-related morbidity

BACKGROUND

In 2009, both Norway and Denmark initiated routine quadrivalent human papillomavirus vaccination (qHPV) for 12-year-old girls; however, Denmark also introduced free-of-charge multi-cohort vaccination for older age groups in 2008. We aim to describe trends in genital warts (GWs) incidence rates (IRs) among men and women and qHPV vaccine coverage among women in Norway and Denmark in 2006-2015.

METHODS

We linked multiple national health registries in Norway and Denmark via national personal identifiers to access data on GWs incidence and qHPV vaccination among women and men aged 12-35 years residing in Norway and Denmark in 2006-2015. We calculated age-specific and age-standardized GWs IRs, GWs IR trends before (2006-2009) and after (2009-2015) the implementation of qHPV vaccination, and qHPV vaccine coverage among women.

RESULTS

In Norway and Denmark together, there were more than 200,000 cases of incident GWs and over 710,000 girls got at least one dose of qHPV vaccine during the study period. The total qHPV coverage in Norway and Denmark in 2015 was among women aged 12-35 years 24% and 70%, respectively. GWs IRs in Norway and Denmark decreased annually in 2009-2015 among women by 4.8% (95% confidence interval: 4.3 to 5.3) and 18.0% (95%CI: 17.5 to 18.6), respectively, and among men 1.9% (95%CI: 1.4 to 2.4) and 10.7% (95%CI: 10.3 to 11.2), respectively. In Denmark, GWs IRs decreased rapidly among both sexes and all age groups after qHPV vaccination, while Norway showed only a modest decrease.

CONCLUSION

Rapid decline in HPV-related morbidity is feasible with high coverage of multi-cohort vaccination. However, the decision to vaccinate a single cohort of 12-years-old girls only will postpone HPV-related disease control by at least a decade. Thus countries planning HPV vaccination programs should also initiate multi-cohort vaccination for faster disease control.

Is the risk for sexually transmissible infections (STI) lower among women with exclusively female sexual partners compared with women with male partners? A retrospective study based on attendees at a Norwegian STI clinic from 2004 to 2014

BACKGROUND

The prevalence of and the risk for sexually transmissible infections (STIs) for women engaging in same-sex sexual behaviour was investigated among women attending an STI clinic.

METHODS

Data from electronic medical records were reviewed and logistic regression used to estimate the odds ratio (OR) of STIs. Women reporting life-time exclusively female partners (WSW) and women reporting female and male partners (WSWM) were compared with women reporting exclusively male partners (WSM). Outcomes included: Chlamydia trachomatis, Mycoplasma genitalium, Neisseria gonorrhoea, HIV and syphilis.

RESULTS

The study population comprised 103564 women (WSW 641, WSWM 12010 and WSM 90913). Overall prevalence of STIs was 8%. Crude OR of STIs for WSW: 0.56 (95% CI 0.39-0.81), for WSWM: 0.99 (95% CI 0.92-1.06) compared with WSM. Multivariate analysis revealed an interaction effect between same-sex sexual behaviour and smoking. Among non-smokers; WSW adjusted OR was 0.41 (95% CI 0.21-0.80), WSWM adjusted OR was 0.91 (95% CI 0.81-1.02) compared with WSM. Among smokers; WSW adjusted OR was 1.03 (95% CI 0.63-1.67) for WSWM adjusted OR was 1.00 (CI 95% 0.93-1.13), compared with WSM.

CONCLUSION

This study, including the largest cohort of women reporting life-time exclusively female partners in an STI study, shows that WSW generally are at lower risk for acquiring STIs than WSM. Smoking WSW, however, had the same risk for acquiring bacterial STIs as WSM and WSWM. Our study suggests that all WSW should receive the same encouragement to test for STIs as WSM.

Overweight and Weight Gain Predict Psoriasis Development in a Population-based Cohort

Overweight is a proposed risk factor for psoriasis. How-ever, evidence from prospective studies is limited. The aim of this study was to investigate the association be-tween overweight, weight gain and risk of psoriasis, and potential synergism with smoking, within a population-based cohort including 8,752 individuals followed from 1994 up to 2008. There was a 32% increased odds of psoriasis from a body mass index (BMI) of 27 kg/m2, in multi-variable logistic regression analysis, further increasing to 43% at BMI 28 kg/m2, and to 71% at BMI ≥ 30 kg/m2 in non-smokers. There was a dose-response association between weight gain from age 25 years, with up to 90% higher odds of psoriasis from middle age, independent of weight category. There was no indication of a synergism between overweight and smoking, and no interaction with sex. Overweight and weight gain represent modifiable risk factors that may be targets for primary prevention of psoriasis.

Mecillinam against genital Chlamydia trachomatis infection: a small-scale proof-of-concept study shows a low cure rate

OBJECTIVES

Mecillinam is highly active in vitro against Chlamydia spp. We aimed to determine whether mecillinam should be evaluated further as treatment for genital Chlamydia trachomatis infection.

PATIENTS AND METHODS

The study was conducted at an open-access clinic for sexually transmitted infections in Oslo, Norway. We planned to include 50 patients. Participants were asymptomatic, heterosexual male patients with a first-void urine sample found to be positive for C. trachomatis by PCR. Treatment consisted of 400 mg of pivmecillinam hydrochloride three times a day for 7 days. A test-of-cure sample, a medication diary and a questionnaire were returned by the participants, and they were used to evaluate treatment outcome, compliance, risk of reinfection and theoretical percentage of time above MIC (t/MIC %). The study was registered in Eudra-CT (no. 2013-002379-179) and clinicaltrals.gov (NCT02083276).

RESULTS

The study was discontinued after including 20 patients, due to a high failure rate. Only two of the 17 participants who delivered a test-of-cure sample were cured. Three participants reported condomless sex before the follow-up sample. When the average or most favourable pharmacokinetics (PK)/pharmacodynamics (PD) reported from other studies were applied in a theoretical model, the estimated t/MIC % was above 50% for all of the 15 participants returning a medication diary. Using the least favourable PK/PD, no participant had t/MIC % of >36%. The mean dose interval was 8 h 36 min (standard deviation 3 h 12 min).

CONCLUSIONS

A low cure rate combined with uncertainty about intracellular availability and attained t/MIC % makes mecillinam an unattractive candidate for further evaluation as treatment for genital C. trachomatis infection.

Elevated odds of metabolic syndrome in psoriasis: a population-based study of age and sex differences

BACKGROUND

Questions remain concerning to what extent age and sex may modify the suggested association between psoriasis and the metabolic syndrome in the general population.

OBJECTIVES

To investigate the association between psoriasis and the metabolic syndrome within a large population-based cohort by age and sex.

METHODS

A cross-sectional study including 10 521 participants aged 30-79 years from the Tromsø Study cohort was performed; 1137 participants reported lifetime psoriasis of a mainly mild character. The new harmonized definition of metabolic syndrome was used in the multivariable logistic regression analysis.

RESULTS

There was a uniformly higher prevalence of metabolic syndrome in men and women with psoriasis compared with those without across all age groups. In women, psoriasis was associated with a 3·8-times higher odds of metabolic syndrome at age 30 years (95% confidence interval 1·5-9·7), with a decreasing odds ratio with increasing age. In men, psoriasis was associated with a stable 1·35-times higher odds of metabolic syndrome (95% confidence interval 1·1-1·6) at all ages. Abdominal obesity was the most frequent metabolic syndrome component in women in this study, and there was indication of a dose-response relationship between psoriasis severity, indicated through treatment, and having a high waistline in women.

CONCLUSIONS

This study suggests age and sex variations in the risk of metabolic syndrome among individuals with psoriasis. Given the high prevalence of psoriasis and the significantly elevated burden of metabolic syndrome in this patient group, there may be a benefit from targeted screening of metabolic syndrome among individuals with psoriasis regardless of age and disease severity.

Psoriasis in Norwegian twins: contribution of genetic and environmental effects

BACKGROUND

Psoriasis is a chronic T-cell-mediated immunological skin disease with a complex pathogenesis where both genetic and environmental factors are involved.

OBJECTIVE

To study the conditional and relative risk of developing psoriasis in identical and fraternal twins whose co-twin has a positive history of the disease and to estimate the relative contribution of genetic and environmental factors on the liability for psoriasis in Norway.

METHODS

Self-reported history of psoriasis in twins from the population-based Norwegian Twin Panel (N = 8045) was studied. Absolute and relative risks of developing psoriasis conditioned on the positive history of psoriasis in a co-twin were calculated by Kaplan-Meier survival analysis and Cox regression, respectively. Structural equation modelling was used to estimate genetic and environmental variance components.

RESULTS

Altogether, 334 (4.2%) of the twins reported having psoriasis. No difference in prevalence of the disease across sexes and zygosity groups was found. Identical twins were more likely to develop psoriasis than fraternal twins if a co-twin reported having the disease. The best-fitting model showed that additive genetic effects could explain 66% of the variation in liability for psoriasis in this population, and the remaining 34% was due to non-shared environmental influences.

CONCLUSIONS

High heritability due to additive genetic effects together with considerable environmental contribution to the liability of psoriasis support the current opinion on the multifactorial aetiology of the disease. No sex-specific patterns of heritability of psoriasis were found.

Psoriasis in Norway as observed in a population-based Norwegian twin panel

BACKGROUND

Psoriasis is a chronic T-cell-mediated immunological skin disease. The occurrence of the disease appears to differ with geography and ethnicity. There is a need for epidemiological data obtained from defined population-based studies, and the sex-specific differences observed in the natural history of the disease require more attention.

OBJECTIVES

To describe the occurrence and risk of psoriasis in Norway by age and sex.

PATIENTS/METHODS

A population-based health survey was conducted in 1998 in Norwegian twins aged 19-31 years. The present study is based upon the self-reported history of psoriasis among the 8045 questionnaire responders.

RESULTS

Altogether, 334 (4.2%) reported a positive history of psoriasis. There were no sex differences in the overall prevalence rates, but significantly higher point-prevalences emerged in females in the teenage-year intervals. A fairly linear increase in incidence rates by every 4-year age-interval peaked at a lower age in females. The mean age at onset was also significantly lower in females (14.8 years) than in males (17.3 years). The absolute risk of developing psoriasis appeared higher for females across the entire age range. However, by the age of 31 the cumulative risks were similar in females and males (0.056 and 0.053, respectively).

CONCLUSIONS

In this historical cohort of Norwegian twins, we find a high prevalence of psoriasis in congruence with previously reported data among whites in north-western Europe. We have found sex-specific characteristics in point-prevalences and incidence rates which may contribute to the understanding of the earlier age at onset of the disease in females.

Screening for ESR mutations in breast and ovarian cancer patients

In the present study, leukocyte DNA from 143 patients with familial clustering of breast and/or ovarian cancer and tumour DNA from 96 breast carcinomas were screened for base mutations in the estrogen receptor gene (ESR). Three patients with a family history of cancer were carrying a Gly160Cys germline substitution. This alteration was also detected in eight (four females and four males) of 729 controls (366 female, 363 males), indicating that the substitution probably represents a polymorphism. However, in the 229 female controls in whom family history of cancer was known, one of two who had a sister with breast cancer was carrying the variant allele. Hence, a possible clinical significance of the glycine into cysteine cannot be completely ruled out and should be further investigated. Somatic mutations were not detected in any of the tumours studied, and the present data do not provide support for somatic ESR base mutations as an important mechanism for hormonal therapy resistance in estrogen receptor-positive breast carcinomas.

Association between the HLA DQB1*0301 gene and human papillomavirus infection in high-grade cervical intraepithelial neoplasia

This study describes the distribution of DQB1genes in Norwegian women treated for high-grade cervical intraepithelial neoplasia (CIN). Formalin-fixed, paraffin-embedded tissue sections from 170 biopsy specimens with diagnoses of CIN II (n = 54) or CIN III (n = 116) were DQB1-typed using allele-specific polymerase chain reaction. The follow-up period for cases was 13 to 15 years. The control material comprised blood samples and endocervical brushes from 213 women without CIN. Both cases and controls had previously been human papillomavirus (HPV)-typed. The DQB1*0301 allele was overrepresented among cases compared with controls (odds ratio [OR] = 1.8). Presence of CIN was related to HPV infection, and HPV 16 positivity was significantly associated with the presence of DQB1*0301 (OR 1.8). The DQBI*0301 allele was significantly more prevalent in CIN III than in CIN II cases. The lesions in two women recurred in the follow-up period, one of whom was carrying the DQB1*0301 allele. Women carrying the HLA-DQB1*0301 allele have an increased risk of developing CIN when infected by HPV 16, although there was not an increased frequency of recurrent disease among women carrying this allele.

Combined effect of smoking and human papillomavirus type 16 infection in cervical carcinogenesis

To study the combined effect of smoking and human papillomavirus (HPV) type 16 infection in high-grade cervical intraepithelial neoplasia, we analyzed data from a Norwegian population-based case-control study including 90 patients and 216 controls, 20-44 years of age. We assessed HPV-16 status both by polymerase chain reaction detecting virus DNA and by enzyme-linked immunosorbent assay detecting antibodies against virus capsid. Smoking was associated with cervical intraepithelial neoplasia grade II-III in HPV-16-positive individuals. Using the jointly unexposed (HPV-16 DNA-negative never-smokers) as the reference group, we determined the risk of cervical intraepithelial neoplasia grade II-III in HPV-16 DNA-positive never-smokers and HPV-16 DNA-positive ever-smokers (odds ratio = 15.7; 95% confidence limits = 3.2, 76.5, and odds ratio = 65.9; 95% confidence limits = 22.3, 194.3, respectively). The estimated proportion of cases among HPV-16-positive smokers that is attributable to the interaction between the two causes is 74%, based on HPV-16 DNA positivity.

An increased risk of cervical intra-epithelial neoplasia grade II-III among human papillomavirus positive patients with the HLA-DQA1*0102-DQB1*0602 haplotype: a population-based case-control study of Norwegian women

Several recent studies have reported different associations between HLA specificities and human papillomavirus (HPV)-associated disease of the cervix. We report the distribution of DQA1 and DQB1 genes and HPV infection in a population-based case-control study including 92 patients with histologically verified cervical intraepithelial neoplasia grade II-III (CIN II-III) (thus including moderate and severe dysplasia and carcinoma in situ) and 225 control subjects. We found an overrepresentation of the DQA1*0102-DQB1*0602 haplotype among HPV-positive cases compared with controls. The association was even stronger when comparing HPV-16-positive cases with HPV-16-positive controls. In addition, among HPV-16-positive individuals, we observed a decreased frequency of DQA1*0102-DQB1*0604 in cases compared with controls. We were not able to detect any association between CIN II-III and DQB1*03. Compared with previous findings in cervical cancer, our data indicate that carrying the DQA1*0102-DQB1*0602 haplotype gives an increased risk of developing CIN when infected with HPV-16, without influencing progression to cancer.

Herpes simplex virus and human papillomavirus in a population-based case-control study of cervical intraepithelial neoplasia grade II-III

In order to evaluate the association between seropositivity for herpes simplex virus (type 1 and type 2) and cervical intraepithelial neoplacia (CIN), we analysed data from a population-based case-control study of CIN grade II-III which included Norwegian women aged 20 to 44 years, 94 cases and 228 controls. Our objectives were to determine if HSV-1 and/or HSV-2 seropositivity were independent risk factors for CIN, taking human papillomavirus exposure into account, and to elucidate the combined effect of HPV positivity and seropositivity for HSV In logistic regression analyses, the association between HSV-2 or HSV-1 seropositivity and CIN II-III was not explained by HPV (adjusted OR 3.0; 95%, CI 1.3-7.2 and adjusted OR 3.3; 95% CI 1.3-8.4, respectively). In analyses restricted to HPV-16 DNA-positive individuals, seropositivity for HSV-2 increased the risk of CIN (OR 11.1; 95% CI 1.2-105.7), whereas HSV-1 seropositivity was not significantly associated with CIN. In women positive for other HPV types, only HSV-1 seropositivity was associated with CIN (OR 8.5; 95% CI 1.3-55.8). In analyses of the HPV-16-seropositive individuals, neither HSV-1 nor HSV-2 seropositivity was associated with CIN. Compared to the reference group of jointly unexposed subjects, the HPV-16 DNA-positive women who were anti-HSV-2 negative had an increased risk of CIN (OR 29; 95% CI 12-67), whereas the risk in women who were both HPV-16 DNA-positive and HSV-2 was OR=247 (95% CI 31-1996). The estimate of interaction was strong, but did not reach significance, and our findings may suggest that the combined effect of the two viruses is of aetiological importance in cervical carcinogenesis. Furthermore, the results indicate that HPV DNA positivity is not sufficient to explain the sexual behaviour-associated risk of cervical neoplasia and that further studies on the role of genital HSV (type 1 as well as type 2) and other STDs are warranted.

Seropositivity against HPV 16 capsids: a better marker of past sexual behaviour than presence of HPV DNA

OBJECTIVES

To assess if seropositivity to human papillomavirus type 16 capsids is a better marker of sexual history than the presence of HPV DNA.

STUDY DESIGN

A population based age stratified random sample of 234 Norwegian women (mean age 32.8 years, range 20-44) was examined for HPV serum antibodies, cervical HPV DNA, cytology and age in relation to sexual behaviour.

RESULTS

Neither age nor age at first sexual intercourse was associated with HPV 16 antibodies. Adjusted ORs for 4-5; 6-10 and > 10 versus 0-1 lifetime sexual partners, were 13.1 (95% CI 1.5-110.8), 8.2 (1.0-69.6) and 10.5 (1.2-94.0) for HPV 16 seropositivity, respectively; and 2.6 (0.2-27.8), 3.4 (0.4-31.7) and 4.1 (0.4-42.8) for HPV 16 DNA positivity, respectively.

CONCLUSION

Seropositivity to HPV 16 capsids is positively associated with the number of sexual partners, suggesting that HPV 16 is predominantly sexually transmitted. The fact that serology had a stronger association with number of sexual partners than viral DNA suggests that seroreactivity is a better measure of lifetime history of HPV infection.

Correlation between polymerase chain reaction and cervical cytology for detection of human papillomavirus infection in women with and without dysplasia

The aim of this study was to compare the ability of two methods, the polymerase chain reaction (PCR) and cervical cytology, to detect HPV infection. The study population included 222 randomly selected women without dysplasia (controls) and 91 women with histologically confirmed dysplasia (CIN II-III) (cases). In women without dysplasia, 8.6% had cytological signs of HPV infection, whereas 15.3% were HPV DNA positive by PCR. In women with dysplasia, 72.5% had cytological signs of HPV infection, whereas 90.1% were HPV PCR positive. The statistical agreement between the two diagnostic methods was low (controls: kappa = 0.26, cases: kappa = -0.03). In total, PCR failed to detect 17 of 85 women with cytological signs of HPV infection, whereas cervical cytology failed to detect 48 of 116 HPV PCR-positive women. In women with dysplasia, but not in women without dysplasia, the oncogenic HPV types were associated with cytological signs of HPV infection.

A population-based case-control study of human papillomavirus-type-16 seropositivity and incident high-grade dysplasia of the uterine cervix

In order to study the association between seropositivity against human papillomavirus-type-16 capsids and CIN II-III in the general population in ages at which high-grade cervical dysplasia arises, 90 cases and 216 controls participating in a population-based case-control study of incident CIN II-III, were analyzed for the presence of HPV antibodies, HPV DNA and for the influence of behavioral factors. A significantly higher proportion of cases than controls were seropositive. Of HPV-16-DNA-positive cases and controls, 42 and 14% respectively were seropositive. A similar proportion of seropositivity was found among the 172 cytologically normal, HPV-DNA-negative controls. However, seropositivity was closely linked to the sexual history of the women. Logistic-regression analyses, adjusting for sexual behavior, smoking history and educational level, revealed that CIN II-III was associated with HPV-16 seropositivity and with HPV DNA. Controlling for the presence of HPV DNA indicated that antibodies were not independently associated with CIN. The low correlation between the presence of HPV antibodies and DNA, the finding that the association between seropositivity and CIN depended on the presence of HPV DNA, and the association of seropositivity with sexual history, may be explained by serology detecting both past and present persistent infections and presence of HPV DNA, reflecting mostly transient infections in controls and persistent infections in cases.

Prevalence of human papillomavirus in cervical scrapes, as analyzed by PCR, in a population-based sample of women with and without cervical dysplasia

HPV is suspected of being a major cause of cancer of the uterine cervix. To understand the risk of disease in the general population of women, it is important to estimate the prevalence of HPV infection in a random population-based sample of women without disease. In this study, a total of 231 randomly selected women without dysplasia (controls) were examined, and compared with 103 women with histologically confirmed CIN II-III (patients). The prevalence of HPV DNA in cervical scrapes was determined by general nested PCR, which was expected to detect any relevant HPV type commonly found in cervical samples. The nested positive samples were typed with type-specific PCR. In the general nested PCR, 15% of the controls were positive, compared to 91% of the patients. In the population-based sample, 2.2% had HPV types 6 and 11 and 10% had types 16, 18, 31, and 33. In both groups, HPV DNA was observed less frequently in women above than below the age of 30. The results are among the few population-based figures on the prevalence of HPV in women, and provide a baseline for understanding the risk of developing cancer of the uterine cervix, and determining the proportion of women to be included in intervention studies.

Human papillomavirus and cervical intraepithelial neoplasia grade II-III: a population-based case-control study

The association between certain human papillomaviruses (HPV) and cervical intraepithelial neoplasia (CIN) is well documented, but there is uncertainty about the strength of association and the role of co-factors is unclear. This population-based case-control study in Norwegian women 20-44 years of age included 103 cases with histologically confirmed CIN II-III and 234 age-matched and randomly selected controls. Cytological specimens from the cervix were analyzed using the polymerase chain reaction (PCR). In all, 91% of the cases and 15% of the controls were HPV DNA positive, giving a crude odds ratio (OR) of 67.2 (95% confidence interval: 28.6-157.5). The association between HPV 16 and CIN II-III was even stronger (crude OR = 123.9; 46.7 - 328.5). In logistic regression analysis, additional to HPV, only a high number of sexual partners and a low educational level contributed independently to the risk. The adjusted OR for the association between HPV and CIN II-III was 72.8 (95% CI: 27.6-191.9). The association between HPV and CIN remains very strong even after adjustment for proposed confounding factors. The results therefore support the role of HPV as a causative agent in the development of CIN.