By K. Craib, A. Weber, P. Cornelisse, S. Martindale, M. Miller, M. Schchter, S. Strathdee, A. Schilder, R. Hogg
In 1985, 83 per cent of all reported AIDS cases were among men who have sex with men. By 1995, the percentage of reported cases in this category had decreased to 74 per cent. Despite this reduction, gay and bisexual men are still greatly affected by the HIV/AIDS epidemic and men having sex with men remains a major source of HIV infections.
While prevention programs were relatively successful, the consistency of safer sexual practices at the individual level are less encouraging. More than 15 years since the beginning of the HIV/AIDS epidemic, young gay and bisexual men may be engaging in higher risk sexual behaviours than older men who have sex with men (MSM).
Comparing two longitudinal studies of gay and bisexual men taken in two distinct time periods may provide a better understanding of the current risk-taking behaviour.
The Vancouver Lymphadenopathy-AIDS Study looked at the lives of more 700 MSM aged 18 to 75 who were from six practices in Vancouver between November, 1982 and December 1984, providing information and having HIV tests every six months until 1986, when follow-ups became annual.
Started in May, 1985, the Vanguard Project (VP) is an ongoing study of over 750 gay and bisexual men aged 18 to 30 living in the Greater Vancouver region. VP participants complete self-administered questionnaires and undergo HIV-testing on an annual basis.
Researchers found that VP participants were younger, less likely to be Caucasian, and less likely to have attended university or college than participants in VLAS. The other sociodemographic differences may be related to the recruitment strategies of the two studies. The VLAS cohort recruited men through general practices while the majority of VP participants were recruited outreach services and media campaigns, as well as clinics and general practitioners. The broader recruitment strategies may help to explain the ethnic and cultural diversity of VP participants.
The two cohorts differed in many ways, including risk behaviours related directly to HIV transmission. VP participants reported a higher mean number of regular and casual male sexual partners in the previous year and were more likely to report engaging in receptive and insertive anal sex with both regular and casual partners than VP participants.
One of the most striking differences between these two cohorts relates to rates of HIV-1 seroconversion. VLAS participants were approximately five times more likely to seroconvert during the 42 month period of follow-up compared to VP participants. The elevated risk of seroconversion among VLAS participants persisted after adjustment of differences in demographics, substance use and sexual behaviour variables between cohorts. The striking difference may be partially explained by the higher prevalence of HIV-1 in the gay community in Vancouver during the mid 1980s in comparison to the mid 1990s. However, the results also indicate that VP participants were far less likely to practice unprotected and intercourse with both casual and regular sexual partners. Consequently, VP participants were far less likely to seroconvert during follow-up.
Overall, the study findings indicate that young gay men in
Vancouver have higher numbers of both regular and casual partners,
are more likely to participate in anal intercourse with these
partners with these partners and more likely to use psychoactive
drugs than their counterparts did 10 years ago. These men also
report a much higher rate of condom use during high-risk sexual
practices. The results clearly suggest that in recent years in
Vancouver, higher rates of condom use among gay men during high-risk
sexual practices has resulted in lower rates of HIV.
For more information, contact:
Bonnie Devlin
Vanguard Project Coordinator
608 - 1081 Burrard Street
Vancouver, BC, Canada, V6Z 1Y6
Tel: (604)806-8306
Fax: (604)806-9044