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Van Den Boom W.,Public Health Service Amsterdam | Stolte I.G.,Public Health Service Amsterdam | Stolte I.G.,Center for Infection and Immunology Amsterdam | Roggen A.,Netherlands Institute for Homosexuality | And 5 more authors.
Health Psychology | Year: 2015

Objective: To investigate site-specific condom-use norms as assumed by visitors of gay venues and websites across The Netherlands and their association with men's own use of condoms. Methods: In 2010, men who have sex with men (MSM) visiting 18 sex venues (e.g., saunas), 30 nonsex venues (e.g., bars), 6 dating websites, and 2 social network websites completed an on-site questionnaire measuring 2 site-specific norms concerning anal sex: descriptive (assumed condom use of others at venue or website) and injunctive (assumed approval of condom use by others at venue or website). We measured the association between assumed descriptive norms and own use of condoms using logistic regression. Results: Among 2,376 participants (median age=30 years; IQR=22-43), 62% (n=1,483) assumed that other visitors would not use condoms. Among men self-reporting on their own use of condoms, 22% (318/1,421) reported condomless anal sex. Men at nonsex venues assumed other visitors would use condoms more often and approved of using them more often compared to men at sex venues. At all sites (venues/websites), men who assumed that others did not use condoms were more likely to have condomless sex themselves. Conclusions: At gay sites across The Netherlands, more than half of MSM believed visitors of these sites would not use condoms during anal sex. The perception that others would not use condoms was associated with less own condom use. HIV prevention should address problematic on-site condom-use norms, as they play a role in influencing sexual behavior between men that meet at these sites. © 2015 American Psychological Association.


Siegenbeek Van Heukelom M.L.,Center for Infection and Immunology Amsterdam | Richel O.,Center for Infection and Immunology Amsterdam | De Vries H.J.C.,Center for Infection and Immunology Amsterdam | De Vries H.J.C.,Public Health Service of Amsterdam | Prins J.M.,Center for Infection and Immunology Amsterdam
Diseases of the Colon and Rectum | Year: 2016

The impact of the treatment of precursor lesions of anal cancer (anal intraepithelial neoplasia) on health-related quality of life has not been investigated. OBJECTIVE: This study aimed to evaluate the impact of 3 treatment options for anal intraepithelial neoplasia on health-related quality of life and sexual functioning in HIV-positive men who have sex with men. DESIGN: The prospective cohort was embedded in a randomized clinical trial evaluating the optimal treatment of anal intraepithelial neoplasia. SETTING: This study was performed at the HIV outpatient clinic of the Academic Medical Center, Amsterdam, the Netherlands. PATIENTS: Included in the study were HIV-positive men who have sex with men with anal intraepithelial neoplasia. INTERVENTION: Treatment with imiquimod (n = 54), topical fluorouracil (n = 48), or electrocautery (n = 46) was given for 16 weeks. MAIN OUTCOME MEASURES: Health-related quality of life and sexual functioning were assessed before, during, and 4 weeks after treatment. Health-related quality of life was assessed using the EQ5D, sexual functioning was assessed using items derived from the International Index of Erectile Function, and the female sexual function index adapted for anal intercourse. RESULTS: One hundred forty-five patients (98%) completed at least 1 questionnaire. There was a significant different pattern of change over time in health-related quality of life among the 3 treatment groups. Patients in the imiquimod group were more likely to report pain/discomfort at week 8 than patients in the electrocautery group. Patients in the electrocautery group were more likely to report anxiety/depression and were less satisfied with their overall sex life at week 16 than patients in the imiquimod and fluorouracil groups, and patients in the electrocautery group were also more likely to report pain/discomfort and problems with usual activities at week 20 than patients in the fluorouracil group. LIMITATIONS: The follow-up method differed slightly among treatment groups. There is no standardized, validated sexual functioning questionnaire for HIV-positive men who have sex with men. CONCLUSIONS: All treatment options have a negative impact on aspects of health-related quality of life. Electrocautery has significantly more negative effects on health-related quality of life than imiquimod and fluorouracil and also has a negative effect on sexual functioning. © 2015 ASCRS.


Matser A.,Public Health Service of Amsterdam | Matser A.,University Utrecht | Vanhommerig J.,Public Health Service of Amsterdam | Vanhommerig J.,Academic Medical Center | And 13 more authors.
PLoS ONE | Year: 2013

Background: Hepatitis C virus (HCV) emerged as sexually transmitted infection among HIV-infected men who have sex with men (MSM). We studied whether HCV circulated in identifiable high-risk MSM subcultures and performed phylogenetic analysis. Methods: HIV-infected MSM were recruited at the sexually transmitted infections (STI) outpatient clinic and a university HIV clinic in Amsterdam, the Netherlands, 2008-2009. Participants completed a detailed questionnaire and were tested for HCV antibodies and RNA, with NS5B regions sequenced for analysis of clusters. Results: Among 786 participants, the median age was 43 (IQR 37-48) years, and 93 (11.8%) were HCV-positive. Seropositivity was associated with belonging to subcultures identified as leather (aOR 2.60; 95% CI 1.56-4.33), rubber/lycra (aOR 2.15; 95% CI 1.10-4.21), or jeans (aOR 2.23; 95% CI 1.41-3.54). The two largest HCV-RNA monophyletic clusters were compared; MSM in cluster I (genotype 1a, n = 13) reported more partners (P = 0.037) than MSM in cluster II (genotype 4d, n = 14), but demographics, subculture characteristics and other risk behaviors did not differ significantly between the two clusters. Discussion: HCV infection is associated with identifiable groups of leather/rubber/lycra/jeans subcultures among HIV-infected MSM. Separate epidemiological HCV transmission networks were not revealed. Active HCV screening and treatment within specific subcultures may reduce HCV spread among all MSM. © 2013 Matser et al.


Matser A.,Public Health Service of Amsterdam | Matser A.,University Utrecht | Luu N.,Public Health Service of Amsterdam | Geskus R.,Public Health Service of Amsterdam | And 6 more authors.
PLoS ONE | Year: 2013

Background:In affluent countries, the prevalence of Chlamydia trachomatis (CT) is often higher in certain ethnic minorities than in the majority population. In the Netherlands, we examined why CT prevalence is higher in Surinamese/Antilleans, the largest minority in the country.Methods:Heterosexuals were recruited for a cross-sectional survey from May through August 2010 at the sexually transmitted infections (STI) clinic in Amsterdam. Participants completed a questionnaire and were tested for STI. A causal directed acyclic graph was assumed to investigate whether the association between ethnicity and CT could be explained by differences in sexual risk behaviour and socio-economic status.Results:Subjects included 1044 with Dutch background and 335 with Surinamese/Antillean background. Median age for the combined population was 25 (IQR 22-30) years, and 55.4% was female. Sexual risk behaviour did not differ significantly between the two groups. CT was diagnosed in 17.9% of Surinamese/Antilleans and in 11.4% of Dutch. Surinamese/Antilleans were significantly more likely to have CT (OR 1.70; 95% CI 1.21-2.38). The association between ethnicity and CT remained statistically significant after adjusting for sexual risk behaviour, age, sex, and ethnic mixing (aOR 1.48; 95% CI 1.00-2.18), but not after adjusting for education and neighbourhood, markers of socio-economic status (aOR 1.08; 95% CI 0.71-1.64).Conclusion:The difference in CT prevalence between the minority and majority groups was not explained by differences in sexual risk behaviour. The higher CT prevalence found among Surinamese/Antilleans appeared to reflect their lower educational level and neighbourhood, two markers of lower socio-economic status. We hypothesise that the effect results from lower health-seeking behaviour. © 2013 Matser et al.


PubMed | Center for Infection and Immunology Amsterdam, Cornell University and DDL Diagnostic Laboratory
Type: Journal Article | Journal: The British journal of dermatology | Year: 2016

Anogenital warts are often presumed to represent nondysplastic or low-grade anal intraepithelial neoplasia (LGAIN). We previously demonstrated that up to 20% of intra-anal warts in HIV-positive men who have sex with men (MSM) contain regions of high-grade AIN (HGAIN).To determine the causative human papillomavirus (HPV) types of low- and high- grade dysplastic areas in warts from HIV-positive MSM.A total of 42 intra-anal warts from 41 HIV-positive MSM were graded as nondysplastic, LGAIN or HGAIN. Whole-tissue sections (WTS) were analysed with the SPF10 polymerase chain reaction/LiPA25 HPV genotyping system. If the WTS contained multiple HPV types, dysplastic regions were isolated by laser capture microdissection (LCM) for HPV genotyping.Overall, 38 of 42 (91%) WTS tested positive for HPV DNA. Of these, 23 (61%) contained a single HPV type and 15 (39%) contained multiple HPV types. All LCM-selected regions contained no more than one HPV type. Ten of 42 (24%) WTS contained HGAIN disease, of which six (60%) were associated with a high-risk HPV (hrHPV) genotype. Twenty-three of 42 WTS contained LGAIN disease, of which two (9%) were associated with hrHPV. AIN lesions containing hrHPV types were identified using p16 staining.LGAIN lesions can be caused by high-risk HPV genotypes and vice versa. We therefore recommend routine follow-up and treatment of all dysplastic intra-anal warts for HIV-positive MSM.


Matser A.,Amsterdam Public Health Service | Urbanus A.,Amsterdam Public Health Service | Geskus R.,Amsterdam Public Health Service | Geskus R.,Academic Medical Center | And 8 more authors.
Addiction | Year: 2012

Aims The hepatitis C virus (HCV) disease burden among injecting drug users (IDUs) is determined by HCV incidence, the long latency period of HCV, competing mortality causes, presence of co-infection and HCV treatment uptake. We examined the effect of these factors and estimated the HCV disease burden in Amsterdam. Design A Markov model was developed, incorporating HCV and human immunodeficiency virus (HIV), and parameterized with data from the Amsterdam Cohort Studies, surveillance studies and literature. Setting IDU population of Amsterdam. Measurements HCV infection simulated from its acute phase to HCV-related liver disease (i.e. decompensated cirrhosis and hepatocellular carcinoma). Findings The HCV prevalence among IDUs in Amsterdam increased to approximately 80% in the 1980s. From 2011 to 2025, the HCV-related disease prevalence will accordingly rise by 36%, from 57 cases (95% range 33-94) to 78 (95% range 43-138), respectively. In total, 945 (95% range 617-1309) individuals will develop HCV-related liver disease. This burden would have been 33% higher in the absence of HIV, resulting in 1219 cases (95% range 796-1663). In Amsterdam, 25% of HIV-negative IDUs receive successful HCV treatment, reducing the cumulative disease burden by 14% to 810 (95% range 520-1120). Further reduction of 36% can be achieved by improving treatment, resulting in 603 cases (95% range 384-851). Conclusions The hepatitis C virus burden among injecting drug users in Amsterdam has been reduced by a high competing mortality rate, particularly caused by HIV infection, and to a smaller extent by hepatitis C virus treatment. Improved hepatitis C virus treatment is expected to contribute to reduce the future hepatitis C virus disease burden. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.


Prince P.D.,Public Health Service of Amsterdam | Matser A.,Public Health Service of Amsterdam | Matser A.,University Utrecht | Van Tienen C.,Erasmus Medical Center | And 3 more authors.
AIDS | Year: 2014

OBJECTIVE:: As compared to HIV-1 infection, HIV-2 is less transmissible, disease progression is slower, and the mortality risk is lower. It has been suggested that HIV-2 infection inhibits the progression of HIV-1 in individuals dually infected by HIV-1 and HIV-2 (HIV-D). We examined whether the mortality rates in dually infected individuals differ from those in persons infected with either HIV-1 or HIV-2. DESIGN:: We conducted a systematic review and meta-analysis. METHODS:: Medline and Embase databases were searched for studies that reported the number of deaths and person-years of observation (PY) for at least two of the three HIV groups (i.e. HIV-1, HIV-2, and HIV-D). Meta-analyses were then performed with random-effects models, estimating combined mortality rate ratios (MRRs). RESULTS:: Of the 631 identified titles, six articles were included in the meta-analysis of HIV-D-infected individuals versus HIV-mono-infected persons, and seven were included in the analysis of HIV-1-mono-infected versus HIV-2-mono-infected individuals. The overall MRR of those infected with HIV-D versus HIV-1 was 1.11 [95% confidence interval (CI) 0.95-1.30]. The overall MRR of those infected with HIV-D versus HIV-2 was 1.81 (95% CI 1.43-2.30) and the MRR of those infected with HIV-1 versus HIV-2 was 1.86 (95% CI 1.44-2.39). CONCLUSION:: HIV-2-mono-infected persons have a lower mortality rate than those mono-infected with HIV-1 and those with HIV-D. There is no evidence that HIV-2 delays progression to death in HIV-D-infected individuals. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.


Matser A.,Public Health Service of Amsterdam | Matser A.,University Utrecht | Heijman T.,Public Health Service of Amsterdam | Geskus R.,Public Health Service of Amsterdam | And 12 more authors.
AIDS and Behavior | Year: 2014

The practice of unprotected anal intercourse (UAI) involves at least two partners. We examined the associations between insertive or receptive UAI and perceived HIV seroconcordance and partnership type in self-perceived HIV-negative and self-perceived HIV-positive men who have sex with men (MSM). MSM (age ≥ 18 years) were recruited for a cross-sectional survey at the sexually transmitted infections clinic in Amsterdam, the Netherlands, in 2008–2009. Participants completed a questionnaire concerning partnerships in the preceding 6 months. Associations were quantified via multinomial logistic regression models using generalized estimating equations. The outcomes were ‘no, or safe anal intercourse’, ‘insertive UAI’, and ‘receptive UAI’. We included 5,456 partnerships from 1,890 self-perceived HIV-negative men and 1,861 partnerships from 558 self-perceived HIV-positive men. Within the partnerships, perceived HIV status of the partner was an important determinant of UAI (p < 0.001). Among HIV-negative men, perceived HIV discordance was negatively associated with receptive UAI compared with no or safe UAI (OR 0.57; 95 % CI 0.36–0.92); when the partners were more familiar with each other, the risk of receptive UAI was increased relative to no or safe anal intercourse. Among HIV-positive men, perceived HIV discordance was negatively associated with insertive UAI (OR 0.05; 95 % CI 0.03–0.08). Within partnerships, perceived HIV status of the partner was one of the strongest determinants of UAI among self-perceived HIV-negative and HIV-positive MSM, and discordant serostatus was negatively associated with UAI. The findings suggest that serosorting is one of the main strategies when engaging in UAI. © 2014, Springer Science+Business Media New York.


Matser A.,Public Health Service of Amsterdam | Matser A.,University Utrecht | Heiligenberg M.,Public Health Service of Amsterdam | Heiligenberg M.,Center for Infection and Immunology Amsterdam | And 8 more authors.
Sexually Transmitted Infections | Year: 2014

Objectives: Decisions to use condoms are made within partnerships. We examined the associations between inconsistent or no condom use and individual and partnership characteristics. We also examined the relative importance of individual versus partnership factors. Methods: Cross-sectional study of heterosexual individuals enrolled from the sexually transmitted infections (STI) outpatient clinic in Amsterdam, the Netherlands, from May to August 2010. Participants completed a questionnaire about sexual behaviour with the last four partners in the preceding year. Participant and partnership factors associated with inconsistent or no condom use in steady and casual partnerships were identified. Results: 2144 individuals were included, reporting 6401 partnerships; 54.7% were female, the median age was 25 (IQR 22-30) years and 79.9% were Dutch. Inconsistent or no condom use occurred in 86.1% of 2387 steady partnerships and in 66.5% of 4014 casual partnerships. There was statistical evidence of associations between inconsistent condom use in steady partnerships and ethnic concordance, longer duration, higher number of sex acts, practising anal sex, and sex-related drug use. In casual partnerships, associations were found with having an older partner, ethnic concordance, longer duration, higher number of sex acts, anal sex, sex-related drug use, ongoing partnerships and concurrency. In multivariable models, partnership factors explained 50.9% of the variance in steady partnerships and 70.1% in casual partnerships compared with 10.5% and 15.4% respectively for individual factors. Conclusions: Among heterosexual STI clinic attendees in Amsterdam, partnership factors are more important factors related with inconsistent condom use than characteristics of the individual.


Van Santen D.K.,Public Health Service Amsterdam | Van Der Helm J.J.,Public Health Service Amsterdam | Grady B.P.X.,Public Health Service Amsterdam | Grady B.P.X.,Center for Infection and Immunology Amsterdam | And 7 more authors.
AIDS | Year: 2014

Objectives: We aimed to identify temporal trends in all-cause and cause-specific mortality rates among people who use drugs (PWUD) compared with the general Dutch population and to determine whether mortality trends differed by hepatitis C virus (HCV)/HIV (co) infection status. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.

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