1. Trends in HIV incidence in the Omega cohort of men who have sex with men (MSM) in Montreal: October 1996 - February 2002 Robert S, Remis, Michel Alary, Joanne Otis, Benoit Mâsse, Eric Demers, Clemon George, Jean Vincelette, BrunoTurmel, René Lavoie, Roger LeClerc, Raymond Parent and the Omega Study Group Department of Public Health Sciences, University of Toronto Unité de recherche en santé des populations (URESP), CHUQ Département de sexologie, Université du Québec à Montréal Département de microbiologie, Pavillon St Luc-CHUM Département de santé publique, Montréal-Centre Séro-Zéro, COCQ-sida Canadian Association of HIV/AIDS Research 11th Annual Scientific Conference Winnipeg, Manitoba, April 25-28, 2002

2. MOHLTC, Laboratories Branch, IMC – 2001 Acknowledgements Physicians who helped to recruit subjectsPhysicians who helped to recruit subjects Gay and HIV-related community organizationsGay and HIV-related community organizations Omega Cohort Study GroupOmega Cohort Study Group Staff, volunteers and Steering Committee membersStaff, volunteers and Steering Committee members funding agencies who supported the study including: funding agencies who supported the study including: 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 The men who contribute their time and energy by participating in the studyThe men who contribute their time and energy by participating in the study

3. MOHLTC, Laboratories Branch, IMC – 2001 Background MSM in Montreal seriously affected by the HIV epidemicMSM in Montreal seriously affected by the HIV epidemic The OMEGA Study is a cohort of 2,000 seronegative gay men whom we are following to better understand HIV transmission in MontrealThe OMEGA Study is a cohort of 2,000 seronegative gay men whom we are following to better understand HIV transmission in Montreal First participant was recruited in October 1996First participant was recruited in October 1996

4. MOHLTC, Laboratories Branch, IMC – 2001 Study objectives Estimate HIV incidence and identify risk factors associated with seroconversion among MSM in Montreal, in particular among those less than 30 years of ageEstimate HIV incidence and identify risk factors associated with seroconversion among MSM in Montreal, in particular among those less than 30 years of age Monitor and characterize changes in sexual behaviour over timeMonitor and characterize changes in sexual behaviour over time Facilitate transfer of knowledge to community groups involved in HIV preventionFacilitate transfer of knowledge to community groups involved in HIV prevention

5. MOHLTC, Laboratories Branch, IMC – 2001 Recruitment and follow-up MSM HIV negative or unknown serostatusMSM HIV negative or unknown serostatus Recruit from clinical and community sitesRecruit from clinical and community sites Follow-up every 6 monthsFollow-up every 6 months Subjects lost to follow-up replacedSubjects lost to follow-up replaced Recruit marginalized MSM and MSM from ethnic minoritiesRecruit marginalized MSM and MSM from ethnic minorities

6. MOHLTC, Laboratories Branch, IMC – 2001 Data and specimen collection A questionnaire, self-administered and interviewer- administered, on:A questionnaire, self-administered and interviewer- administered, on: Demographic factorsDemographic factors Sexual behaviours during lifetime and previous 6 monthsSexual behaviours during lifetime and previous 6 months Psychosocial dataPsychosocial data Subjects tested for HIV, syphilis and HBVSubjects tested for HIV, syphilis and HBV

7. MOHLTC, Laboratories Branch, IMC – 2001 Characteristics of participants (n=1,787) Age <205%<205% 20-2942%20-2942% 30-3932%30-3932% 40-4915%40-4915% 50+6%50+6%Education None7%None7% High school23%High school23% CEGEP23%CEGEP23% University 46%University 46%

8. MOHLTC, Laboratories Branch, IMC – 2001 Characteristics of participants (n=1,787) Residence Montreal Island88%Montreal Island88% Elsewhere12%Elsewhere12% Place of birth Quebec71%Quebec71% Canada, elsewhere12%Canada, elsewhere12% Other country17%Other country17%Language French only79%French only79% English only12%English only12% Both8%Both8% Other1%Other1%

9. MOHLTC, Laboratories Branch, IMC – 2001 Factors associated with HIV infection at baseline nHIV+p-value Age (years) <25 25 – 34 35 – 44 45+All4556844242231,7860.88%2.0%2.9%0.00%1.8%0.007 Education NoneDES/DECHigher1127006997.4%1.4%0.86%0.001

10. MOHLTC, Laboratories Branch, IMC – 2001 Factors associated with HIV infection at baseline nHIV+p-value Ethnicity French-CanadianEnglish-CanadianOther1,3321382791.4%1.4%3.6%0.04 Age at first homosexual sex <1515-2020+3954863163.3%1.2%0.00% 0.002 0.002

11. MOHLTC, Laboratories Branch, IMC – 2001 Factors associated with HIV infection at baseline <0.00011.1%0.0%10.3%3.9%11.7%1,57332582660 Injected drugs NeverRarelySometimes Fairly often Very often p-valueHIV+n

12. MOHLTC, Laboratories Branch, IMC – 2001 Factors associated with HIV infection at baseline nHIV+p-value Number of casual partners, lifetime 0-56-4950+3797105850.79%1.3%2.8%0.03 Number of regular partners, lifetime 01-99100+551,685383.6%1.6%5.3%NS

13. MOHLTC, Laboratories Branch, IMC – 2001 Incidence density among subjects with two or more visits (n=1,436) Age Sero- conversions Person- years Incidence density (95% CI) <30 30+ 30+11121,4932,549 0.74 (0.37, 1.3) 0.47 (0.20, 0.74) Total234,041 0.57 (0.34, 0.80)

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

15. MOHLTC, Laboratories Branch, IMC – 2001 Limitations Data on behaviours self-reported and not independently validatedData on behaviours self-reported and not independently validated Subjects not necessarily representative of gay men in MontrealSubjects not necessarily representative of gay men in Montreal Selective attrition may introduce biasSelective attrition may introduce bias

16. MOHLTC, Laboratories Branch, IMC – 2001 Conclusions HIV prevalence at baseline related to age, education, injection of drugs and age at first homosexual sexHIV prevalence at baseline related to age, education, injection of drugs and age at first homosexual sex Overall, HIV incidence in a cohort of Montreal MSM has been relatively low and stableOverall, HIV incidence in a cohort of Montreal MSM has been relatively low and stable However, increase observed in 2001-02 compared to 2000 may be real, especially in light of increasing risky sexual behaviourHowever, increase observed in 2001-02 compared to 2000 may be real, especially in light of increasing risky sexual behaviour Trends in HIV incidence are different in younger and older MSMTrends in HIV incidence are different in younger and older MSM