An Australian study published in the December edition of Sexually Transmitted Infections has found that the characteristics of a sexual encounter between gay men rather than gay men’s individual characteristics predict whether or not unprotected anal sex will occur. The investigators suggest that this is a major finding and that health promotion workers need to stop thinking about certain individuals having a propensity to engage in unprotected sex, but rather recognise that “the occurrence of unprotected anal intercourse…is significantly shaped by characteristics and context of the specific sexual encounter.”
In the past investigators have attempted to see if gay men’s social and demographic characteristics could predict if they had a greater risk of engaging in unprotected anal sex. Other research has focused on the influence of social networks. Investigators have also looked at the characteristics of sexual encounters where unprotected anal sex took place.
Investigators from the Victorian Networks Study (Vines) in Melbourne, Australia wished to further explore the complexity of gay men’s sexual activities by simultaneously considering the relationship between an individual’s characteristics, their social networks, and the characteristics of their recent sexual encounters. By doing this they hoped to show which factors were associated with protected and unprotected anal sex.
They designed a cross-sectional study involving 202 men recruited from gay community venues in Melbourne in 2002. In interviews they provided detailed information on 733 sexual events.
Most of the men (91%) identified as gay, 79% were born in Australia, 70% were in employment, 60% had received a college education and the mean age was a little under 37.
Almost three-quarters of the men (73%) said they were HIV-negative, with 16% being HIV-positive and 11% reporting that they did not know their HIV infection status.
Only 17% of men reported ever having injected drugs, and over half of these said that they had not injected drugs in the last year.
Nearly half of the men reported social networks that consisted of a majority of men, but only 37% of networks were mostly gay, and a similar proportion of networks were entirely HIV-negative.
The investigators then looked at the men’s reported sexual behaviour. The median number of sexual encounters per man was four. The majority of these encounters (56%) did not involve any anal sex. Of the other encounters, 31% involved protected anal sex and 13% involved unprotected anal sex.
Most the sexual encounters were with casual or occasional partners (85%), with the remaining 15% of encounters being with a regular partner.
HIV status was only known for 31% of encounters.
Just over a third of encounters took place at the home of the other sexual partner, a quarter of encounters took place within the men’s own home, 13% of encounters took place whilst cruising, 15% in saunas, and 6% in sex on the premises venues.
A total of 70 men (35%) reported at least one episode of unprotected anal sex. There was no relationship between age, education, country of birth, sexual identity, or employment with unprotected anal sex.
Significant predictors of unprotected anal sex were injecting drug use in the last year (adjusted odds ratio: 9.97), uncertainty of a partner’s HIV infection status (adjusted odds ratio, 3.00), having sex at the partner’s home (adjusted odds ratio, 1.99), having sex in a sauna (adjusted odds ratio, 1.91), and having sex in a sex on the premises venue (adjusted odds ratio, 17.99).
Of the 96 episodes of unprotected anal sex, eleven (2%) occurred between partners known or believed to be HIV serodiscordant.
“This paper substantially advances our understanding of the complexity of homosexual and bisexual men’s sexual practice”, comment the investigators. They stress that, for the first time, a study included the characteristics of individuals, their social networks, and details of their sexual encounters.
The investigators believe that their work has important implications for HIV prevention activities. First, health promotion workers should take into account the settings where sex takes place. Second, their research found that men often engage in both protected anal sex and unprotected anal sex.
Smith AMA et al. Individual characteristics are less important than event characteristics in predicting protected and unprotected anal intercourse among homosexual and bisexual men in Melbourne, Australia. Sexually Transmitted Infections 82: 474 – 477, 2007.