Evidence unclear as to whether gay men are having more risky sex

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Has the number of gay men having unprotected anal sex with casual partners increased since the introduction of HAART? That's a question with no easy answer according to research from the USA, Canada and Europe presented to the XIV International AIDS Conference in Barcelona on 9 July 2002.

Although studies conducted in the USA and Canada, did find apparent increases in risky behaviour, research from Amsterdam found that behaviour was associated with age and data from Spain suggested stable patterns of sexual risk behaviour. Or could it be that more subtle processes are at work, including an increased willingness of gay men to admitt to behaviour which is disapproved of?

Evidence for more risky sex taking place came from research carried out in California. A study conducted by the STOP AIDS Project in San Francisco found that in 2000, of the 1,118 gay men reporting unprotected anal sex in the past twelve months, 20% said that this had been with a partner whose HIV status they did not know.

Glossary

risky behaviour

In HIV, refers to any behaviour or action that increases an individual’s probability of acquiring or transmitting HIV, such as having unprotected sex, having multiple partners or sharing drug injection equipment.

person years

In a study “100 person years of follow-up” could mean that information was collected on 100 people for one year, or on 50 people for two years each, or on ten people over ten years. In practice, each person’s duration of follow-up is likely to be different.

sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

syphilis

A sexually transmitted infection caused by the bacterium Treponema pallidum. Transmission can occur by direct contact with a syphilis sore during vaginal, anal, or oral sex. Sores may be found around the penis, vagina, or anus, or in the rectum, on the lips, or in the mouth, but syphilis is often asymptomatic. It can spread from an infected mother to her unborn baby.

Further north American evidence of more casual anal sex taking place without condoms came from Canada. Data from Montreal suggested that although HIV incidence remained stable between 1996 and 2001 in a cohort of 2,000 gay men at 0.44 to 0.79 incidences per 100 person years, gay men reported to investigators that they were more likely to have had unprotected anal sex with casual partners (8.2% in 1996 compared to 12.8% in 2001).

However, the north American evidence is contradicted in part by European research. A study conducted amongst a sample of approximately 800 gay men in Barcelona in 1995, 1998 and 2000 found that in each year almost identical numbers of gay men reported unprotected anal sex with casual partners (24.2% in 1995, 21.8% in 1998 and 25.4% in 2000).

The picture is further complicated when a study conducted amongst gay men attending a sexual health clinic in Amsterdam (which has already reported on aidsmap) is considered. This found that gay men men aged 35 and above were more most closely associated with an increase in rates of risky sexual practices (judged by increased rates of HIV diagnoses and the detection of gonorrhoea and syphilis).

Apparent increases in risk behaviour could be attributable to an increased willingness amongst gay men to honestly report their sexual behaviour to researchers, as suggested by the UK National Surveys of Sexual Attitudes and Lifestyles. The surveys, conducted in 1990 and 2000 found increased numbers of gay men reporting anal sex, which may, the researchers believe, be due not to an increase in the amount of anal sex gay men are having but to an increased acceptance of gay sex in British society generally.

This raises an interesting question. Are studies which apparently find increased rates of unprotected anal sex between casual gay sexual partners in fact partly finding that gay men are simply more confident about admitting to having a form of sex which earlier HIV campaigns stressed was taboo? A subject for a presentation at the 2004 conference?

References

Mecer CH: Changing patterns of homosexual partnership in Britain: Evidence from the 1990 and 2000 Surveys of Sexual Attitudes and Lifestyles.

XIV International AIDS Conference, Barcelona, oral presentation 9 July 2002

Remis RS: Trends in HIV incidence and sexual behaviour among a cohort of men who have sex with men in Montreal, 1996-2001. XIV International AIDS Conference, Barcelona, oral presentation 9 July 2002

Perez K: No evidence of changes in HIV prevalence and risk behaviours among men who have sex with men in Barcelona, 1995-2000. XIV International AIDS Conference, Barcelona, oral presentation 9 July 2002

Chen s: High levels of unprotected anal sex between HIV serodiscordant men who have sex with men, San Francisco. XIV International AIDS Conference, Barcelona, oral presentation 9 July 2002.