AEGiS-14IAC: Trends in HIV incidence and sexual behaviour among a cohort of men who have sex with men (MSM) in Montreal, 1996-2001.

14th International AIDS Conference

Barcelona, Spain - July 7-12, 2002

Trends in HIV incidence and sexual behaviour among a cohort of men who have sex with men (MSM) in Montreal, 1996-2001.

Int Conf AIDS 2002 Jul 7-12; 14:(abstract no. TuOrC1146)

Remis RS, Alary M, Otis J, Demers E, Masse B, George C, Vincelette J, Turmel B, Lavoie R, LeClerc R, Parent R
University of Toronto, Toronto, Canada

BACKGROUND: To determine trends in HIV incidence and sexual behaviour among MSM in Montreal.

METHODS: The Omega Cohort study recruits MSM not known to be HIV-positive. HIV testing is performed and a questionnaire completed at study entry and every 6 months.

RESULTS: From October 1996 to August 2001, we recruited 1,699 participants, of whom 29 (2.0%) were HIV-positive at baseline. Prevalence at baseline varied by age (p=0.02): <25 0.92%, 25-34 2.0%, 35-44 (3.0%) and 45+ years 0.0%. 1,347 initially HIV-negative participants had 1+ follow-up visits, yielding 3,541 person-years (py). To date, we observed 20 seroconversions, for a crude HIV incidence of 0.56 per 100 py (95% CI 0.32,0.81). Annual HIV incidence varied from 0.44 to 0.71 per 100 py over the five-year period without any clear increasing or decreasing trend. However, HIV incidence varied by age and an increase was observed in 2001. The relative rates in 2001 over 2000 were 2.7 for younger MSM and 1.3 for older MSM. The confidence limits for incidence in 2001 were wide (incidence 0.71, 95% CI 0.00, 1.57) and the increase, either crude or by age group, did not approach statistical significance. We also observed statistically significant increases in risky sexual behaviours (latest versus earliest period): unprotected anal sex with casual partner (12.8% vs 8.2%, p<0.01), unprotected anal sex with HIV+ or HIV? partner (20.7% vs 15.7%, p<0.01). Increases in risky behaviour were evident in both younger and older MSM.

CONCLUSIONS: Overall, HIV incidence among MSM in Montreal has not increased significantly over the study period. However, the increase observed in 2001 is of potential concern and will require ongoing close monitoring. We also observed a statistically significant increase in risky sexual behaviours among Cohort members, suggesting that the increase in HIV incidence in 2001 may be real.

Keywords: AEGIS, Sex Behavior, Incidence, HIV Infections, Coitus, HIV Seropositivity, Safe Sex, Prevalence, Cohort Studies, Human, Male, epidemiology

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