1. Trends in HIV incidence and sexual behaviour in a cohort of men who have sex with men (MSM) in Montreal, 1996-2003 Robert S. Remis, Michel Alary, Joanne Otis, Eric Demers, Benoit Mâsse, Clemon George, Jean Vincelette, Bruno Turmel, René Lavoie, Roger LeClerc, Raymond Parent and the Omega Study Group Canadian Association of HIV/AIDS Research 13th Scientific Conference Montreal, Quebec, May 13-16, 2002

2. MOHLTC, Laboratories Branch, IMC – 2001 Background MSM in Montreal seriously affected by the HIV epidemicMSM in Montreal seriously affected by the HIV epidemic Omega was a cohort study of over 1,800 seronegative MSM to monitor and characterize HIV transmission in MontrealOmega was a cohort study of over 1,800 seronegative MSM to monitor and characterize HIV transmission in Montreal First subject recruited October 1996First subject recruited October 1996 Study ended in June 2003 (6.7 years)Study ended in June 2003 (6.7 years)

3. MOHLTC, Laboratories Branch, IMC – 2001 Study objectives Estimate HIV incidence and identify risk factors associated with seroconversion among Montreal MSMEstimate HIV incidence and identify risk factors associated with seroconversion among Montreal MSM Monitor and characterize trends in sexual behaviourMonitor and characterize trends in sexual behaviour Facilitate transfer of knowledge to community groups for HIV preventionFacilitate transfer of knowledge to community groups for HIV prevention

4. MOHLTC, Laboratories Branch, IMC – 2001 Recruitment and follow-up MSM HIV-negative or unknown serostatusMSM HIV-negative or unknown serostatus Recruited from community and clinical sitesRecruited from community and clinical sites Follow-up visit every 6 monthsFollow-up visit every 6 months Continuous recruitment to replace those lost to follow-upContinuous recruitment to replace those lost to follow-up Attempted to oversample younger (<30 years) and marginalized MSM and those from ethnic minoritiesAttempted to oversample younger (<30 years) and marginalized MSM and those from ethnic minorities

5. MOHLTC, Laboratories Branch, IMC – 2001 Data and specimen collection Self-administered and interviewer administered questionnaires on:Self-administered and interviewer administered questionnaires on: Demographic characteristicsDemographic characteristics Sexual behaviours, lifetime and previous 6 monthsSexual behaviours, lifetime and previous 6 months Psychosocial dataPsychosocial data HIV and syphilis test at each visitHIV and syphilis test at each visit

6. MOHLTC, Laboratories Branch, IMC – 2001 Statistical analysis Trends in sexual behaviour Calendar time divided into six-month periodsCalendar time divided into six-month periods Each subject presenting at a particular calendar visit includedEach subject presenting at a particular calendar visit included Trend analysis: General estimating equation (GEE) to control for multiple visits by the same subjectTrend analysis: General estimating equation (GEE) to control for multiple visits by the same subject

7. MOHLTC, Laboratories Branch, IMC – 2001 Statistical analysis Analysis of HIV incidence HIV incidence calculated by yearHIV incidence calculated by year Trends in HIV incidence using “bootstrap”Trends in HIV incidence using “bootstrap” Analyzed risk factors for HIV seroconversion with Cox proportional hazards regression modelAnalyzed risk factors for HIV seroconversion with Cox proportional hazards regression model

8. MOHLTC, Laboratories Branch, IMC – 2001 Characteristics of participants (n=1,892) AgeMedian 31, IQR 25–38 years EducationCollege/university 67% ResidenceMontreal Island 89% Place of BirthQuebec 71%, Canada other 12% LanguageFrench only 78%, English only 12%

9. MOHLTC, Laboratories Branch, IMC – 2001 HIV prevalence at baseline by age

10. MOHLTC, Laboratories Branch, IMC – 2001 HIV prevalence at baseline by education EducationnHIV+p-value < Secondary Secondary/collegeHigher1127006997.6%3.2%1.8%0.0002

11. MOHLTC, Laboratories Branch, IMC – 2001 HIV prevalence at baseline by drug injection

12. MOHLTC, Laboratories Branch, IMC – 2001 Incidence density among subjects with two or more visits (n=1,592) Age Sero- conversions Person- years Incidence density (95% CI) <30 30+ 30+13201,8453,497 0.70 (0.32, 1.09) 0.57 (0.32, 0.82) Total335,342 0.62 (0.41, 0.83)

13. MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence by age group and study year

14. MOHLTC, Laboratories Branch, IMC – 2001 Risk factors for HIV seroconversion, Cox proportional hazards regression model 0.96-4.32.0<0.0013.9 Risky oral sex 2.3-11.35.1<0.0018.4 UAS exc HIV-neg regular partners 95% CI RRP-valueRR 0.73-3.5 1.1-5.1 1.60.0023.2 Frequent use of drugs or alcohol before sex 2.4<0.0014.2 > 5 casual partners Multivariate Analyses Univariate Analyses Risk Factor

15. MOHLTC, Laboratories Branch, IMC – 2001 Proportion UAS by type of partner, 584 subjects followed to T8

16. MOHLTC, Laboratories Branch, IMC – 2001 Proportion of UAS by partner type, all participants, by 6-month period

17. MOHLTC, Laboratories Branch, IMC – 2001 Limitations Data on behaviours self-reportedData on behaviours self-reported Subjects not necessarily representative of MSM in MontrealSubjects not necessarily representative of MSM in Montreal Selective attrition may introduce biasSelective attrition may introduce bias

18. MOHLTC, Laboratories Branch, IMC – 2001 Conclusions HIV prevalence at baseline related to age andHIV prevalence at baseline related to age and drug injection HIV incidence remains relatively low (<1.0 per 100 p-y) though non-negligible, among MSM in Montreal (estimated 300-400 annual infections)HIV incidence remains relatively low (<1.0 per 100 p-y) though non-negligible, among MSM in Montreal (estimated 300-400 annual infections) Unprotected anal sex remains the main risk factor for HIV acquisition, though also associated with number of casual partnersUnprotected anal sex remains the main risk factor for HIV acquisition, though also associated with number of casual partners Role of risky receptive oral somewhat unclear; may be due to a classification biasRole of risky receptive oral somewhat unclear; may be due to a classification bias

19. MOHLTC, Laboratories Branch, IMC – 2001 Conclusions (continued) Though relatively modest, the increased frequency of unprotected anal sex is concerningThough relatively modest, the increased frequency of unprotected anal sex is concerning Though not statistically significant, HIV incidence has increased steadily since 2000Though not statistically significant, HIV incidence has increased steadily since 2000 HIV incidence must be closely monitored since increase in risky behaviours may precede increase in HIV incidenceHIV incidence must be closely monitored since increase in risky behaviours may precede increase in HIV incidence Need to reinforce preventive interventions aimed at reversing trendsNeed to reinforce preventive interventions aimed at reversing trends

20. MOHLTC, Laboratories Branch, IMC – 2001 Acknowledgements Gay and HIV-related community organizationsGay and HIV-related community organizations Staff, volunteers and Steering Committee membersStaff, volunteers and Steering Committee members Funding agencies who supported the study: Funding agencies who supported the study: Canadian Institutes for Health ResearchCanadian Institutes for Health Research Centre québécois de coordination du sidaCentre québécois de coordination du sida Fonds de la recherche en santé du QuébecFonds de la recherche en santé du Québec Men who contributed their time and energy by participating in the studyMen who contributed their time and energy by participating in the study