Recent increases in HIV-related sexual risk-taking between men in London and Glasgow began at different times and were affected by distinctive factors, according to a comparison of gay men's sex surveys published in the June issue of The Journal of Acquired Immune Deficiency Syndromes.
The authors suggest that each city requires individualised, specialised targeted prevention work to tackle the underlying stigma and discrimination that prevents a higher uptake of HIV testing in Glasgow, and to reduce high-risk sex between men of different or unknown HIV-status in London.
Previous studies reporting an increase in HIV-related sexual risk-taking between men in both London - England's largest city - and Glasgow - Scotland's largest city - have previously been reported on aidsmap.com.
Although there may be common factors affecting these higher levels of sexual risk-taking, it is possible that city-specific factors are also associated with these increases. Consequently, sexual health interventions that may be effective in one city may not necessarily work elsewhere.
Investigators from London and Glasgow compared trends in HIV-related sexual risk behaviour to find out whether city-specific differences could be seen. They hoped that any differences could help in the development of future health promotion interventions.
They used data from sexual health surveys carried out in gay bars, clubs, and saunas London. These data are slightly different from the London gay men's gym surveys.
In Glasgow, data were collected from most of the exclusively gay bars in the city. Both cities used anonymous, self-completed questionnaires to collect data on demographics, HIV testing and sexual behaviour in the previous year.
A total of 8,247 men completed the questionnaires. In 1996, a total of 1,895 (a 75% response rate) men participated in London and 1,245 (77%) men participated in Glasgow. Numbers for 1999 were 1,368 (74%) in London and 1,442 (75%) in Glasgow. In 2002, a total of 1,325 (77%) participated in London and 972 (63%) participated in Glasgow.
HIV testing
The total numbers of men who had ever been tested for HIV were considerably higher in London than in Glasgow (p
In addition, whereas HIV testing increased in London over time, there was no significant change in Glasgow.
The investigators note that, "barriers to HIV testing among Scottish gay men have been the focus of attention, and it is recognized that there is a need to combat the stigma and discrimination that still surround HIV. This remains a specific challenge for sexual health promotion in Glasgow."
Unprotected anal intercourse (UAI)
Although London men reported higher numbers of UAI partners than Glasgow men (p
In fact, in 2002, the percentage of men practising UAI with partners of either unknown or different HIV status was higher in Glasgow than in London (27 vs. 21%; p
"It is possible," write the investigators, "that this is a direct result of the lower HIV testing levels in Glasgow. Never-tested men have previously been reported to be more likely to assume that their partners are HIV negative."
Assessing trends
The investigators used multivariate logistic regression to assess the trends in sexual risk-taking, adjusting for age, employment status and HIV testing.
Compared with 1996, the odds of any UAI, of UAI with partners of either unknown or different HIV status, and of UAI with more than one partner increased significantly in London (p
In Glasgow no significant changes in each of these risk behaviours were seen between 1996 and 1999. However, significant increases were seen between 1999 and 2002. Compared with 1999, the odds of any UAI, of UAI with partners of either unknown or different HIV status, and of UAI with more than one partner increased significantly (p
The increases in risk behaviour were found to be independent of HIV testing status.
Comparing cities
The investigators found that although there have been significant changes in HIV-related sexual risk-taking in both cities, and patterns of increase were similar, there were some differences: the increases began earlier in London than in Glasgow; HIV testing levels were considerably lower in Glasgow; and although overall risk levels were higher in London, UAI with partners of either unknown of or different HIV status was found to be higher among Glasgow men.
They note that between 1996 and 1999, when sexual risk-taking was stable in Glasgow, the Gay Men's Task Force - sexual health promotion targeted to gay men - was underway. By 2002, this intervention had been considerably reduced in Glasgow, and they argue that this may have contributed to the increase in levels of risk reported.
They suggest there each city's distinguishing factors may require different kinds of interventions. If Glasgow's lower levels of HIV testing is resulting in higher rates of UAI with partners of unknown HIV status, they write, "this highlights the need for prevention work to target the continued stigma and discrimination surrounding HIV testing and to encourage HIV testing in Glasgow." However, since the rate of increase in UAI with partners of unknown or different HIV status is higher in London, this "requires highly focused health promotion."
They conclude by saying that "the transferability of sexual health interventions remains uncertain, and recognition of such differences could aid the development of more effective interventions. Regular behavioral surveillance combined with data on incident HIV and other sexually transmitted infections should inform the development of appropriate interventions at the city level."
Williamson, LM et al. Increases in HIV-related sexual risk behavior among community samples of gay men in London and Glasgow: how do they compare? J Acquir Immune Defic Syndr 42: 238-241, 2006.