Trends in sexual behaviour among London homosexual men 1998-2003: implications for HIV prevention and sexual health promotion.

OBJECTIVES: To examine changes in sexual behaviour among London homosexual men between 1998 and 2003 by type and HIV status of partner.
METHODS: Homosexual men (n=4264) using London gyms were surveyed annually between 1998 and 2003 (range 498-834 per year). Information was collected on HIV status, unprotected anal intercourse (UAI) in the previous 3 months, and type of partner for UAI. High risk sexual behaviour was defined as UAI with a partner of unknown or discordant HIV status.
RESULTS: Between 1998 and 2003, the percentage of men reporting high risk sexual behaviour with a casual partner increased from 6.7% to 16.1% (adjusted odds ratio (AOR) 1.36 per year, 95% confidence interval (CI) 1.26 to 1.46, p <0.001). There was no significant change in the percentage of men reporting high risk sexual behaviour with a main partner alone (7.8%, 5.6%, p=0.7). These patterns were seen for HIV positive, negative and never tested men alike regardless of age. The percentage of HIV positive men reporting UAI with a casual partner who was also HIV positive increased from 6.8% to 10.3% (AOR 1.27, 95% CI 1.01 to 1.58, p <0.05).
CONCLUSION: The increase in high risk sexual behaviour among London homosexual men between 1998 and 2003 was seen only with casual and not with main partners. STI/HIV prevention campaigns among London homosexual men should target high risk practices with casual partners since these appear to account entirely for the recent increase in high risk behaviour.