This abstract was
presented orally at the 11th Annual Canadian Conference on HIV/AIDS Research in
Winnipeg in April 2002, and will be presented as a poster at the
AIDS Conference to be held in Barcelona, Spain, in July 2002.
Predictors of HIV seroconversion among young gay men
who have sex with men
Amy E. Weber,
Kevin J.P. Craib, Keith Chan, Steve Martindale, Mary Lou Miller,
Darrel A. Cook*, Martin T. Schechter, Robert S. Hogg
The Vanguard Project, BC Centre for Excellence
in HIV/AIDS, Vancouver, BC;
amd (*) the BC Centre for Disease Control, Vancouver, BC.
To identify demographic and behavioural characteristics associated
with HIV seroconversion.
Men aged 15 to 35 years were enrolled in a cohort study of
MSM in the Greater Vancouver region. Eligible men completed a
baseline and at least one follow-up questionnaire between May
1995 and September 2001. Men who were HIV-negative at baseline
were followed prospectively to calculate the HIV incidence in
the cohort. Time-dependent Cox proportional hazards regression
was used to determine predictors of seroconversion.
Thirty-six incident HIV cases were identified over the course
of the study period, (HIV incidence 1.9/100 person-years). Men
with at least a high school education (Risk Ratio (RR:0.2), lived
in stable housing (RR:0.1) or were employed (RR:0.2) were less
likely to seroconvert. Men who were of Aboriginal ethnicity (RR:2.7),
had ever been in at psychiatric ward (RR: 6.9), a group home (RR:
6.7) or in prison (RR: 7.9) were at increased risk of seroconversion.
Involvement in the sex trade was associated with a five-fold increase
in the risk of seroconversion. Unprotected insertive (RR: 3.5)
and receptive (RR: 5.1) anal sex with an HIV positive partner
was associated with seroconversion. Injection drug use was associated
with seroconversion (RR:7.0). The use of marijuana (RR:2.9), crystal
methamphetamine (RR:3.1), cocaine (RR:4.1), poppers (RR:2.2),
crack (RR:6.5) and heroin (RR:4.6) were all associated with seroconversion.
Multivariate analysis revealed unprotected receptive anal intercourse
with HIV-positive partners (Adjusted Risk Ratio (ARR):6.5 and
with casual partners regardless of serostatus (ARR:4.9) to be
independently associated with seroconversion. Further predictors
of seroconversion were having ever been in prison (ARR: 6.0) or
in a psychiatric ward (ARR:3.8).
These data provide evidence that HIV prevention efforts should
address issues related to mental and social stability in addition
to serodiscordant relationships and unprotected sex in order to
reduce the risk of seroconversion among young MSM.