Shift of preference of location for sexual partnership in men having sex with men in an Asian population

Abstract

In Hong Kong, heterosexual transmission has long been the major mode of HIV spread. Reported HIV infection has, however, gradually risen in men who have sex with men (MSM), overtaking heterosexual contacts in men as the main route of HIV transmission after the year 2004. A survey in 2006/ 2007 confirmed that 4% of tested MSM were positive for HIV antibody. Engaging in unsafe sex is often considered the reason behind the rising HIV prevalence in MSM. To understand the dynamics of HIV transmission in Hong Kong, we conducted a study to explore the partnership pattern of MSM before their HIV diagnosis. In the 8-week period between November 2006 and January 2007, 121 HIV-positive Chinese MSM attending a specialist clinic were successfully interviewed. Overall, 53 (46.1%) were infected during or before 2000, whereas 62 (53.9%) were infected afterwards. Using the same cut-off year, the age of infection was higher (33.7 v. 30.1, t= –2.02, P< 0.05) in those infected after v. during or before 2000. There was in general a 1–2 year lag period between infection and diagnosis, a phenomenon that has not changed over years. A Likert scale was used to assess mixing pattern and sexual activities. A majority indicated that their sex partners were people of similar age (72%) or not more than 10 years older or younger. A higher proportion of older individuals above the age of 38 had sex partners more than 10 years younger (27.9% v. 10.3% odds ratio [OR] 3.35; 95% confidence interval [CI] 1.22–9.23), but there has been no change after 2000. Over 90% expressed that they largely (Likert scale 4–6) had sex with local Chinese. There was no demonstrable difference in the pattern of mixing in terms of age and ethnicity, between those infected during or before and after 2000. The type of sexual activities was assessed. There was no statistically significant difference during or before and after 2000 in the proportion of respondents who practised anal sex (54.7% v. 62.9%), oral sex (79.2% v. 83.9%) and/or masturbation (84.9% v. 85.5%) predominantly (Likert scale 4–6). The use of a condom for anal sex has remained the same (64.2% v. 68.3%), whereas that for oral sex has, however, declined (21.2% v. 9.8%, OR= 2.2, P < 0.05). Similarly, the proportion of those admitting the use of soft drugs has increased (39.6% v. 53.2%, OR= 1.73, P < 0.05) after 2000. Table 1 shows the distribution of locations that MSM in our study population used for sourcing partners and for sex. The internet has become one of the most important modes of becoming acquainted with sex partners after 2000 (45.2% v. 7.5% OR= 10.09, P< 0.05). The frequency of anal sex was higher in internet users (71.4% v. 50.8%, OR= 2.41, P < 0.05), but there was no difference in the use of condom for both anal and oral sex. Interestingly, the respondents’ home has now stood as one of the most popular locations for sex for those infected after 2000 (26.4% v. 45.2%, OR= 2.29, P < 0.05). In this study we observed major changes in the networking pattern of Chinese MSM in Hong Kong, a phenomenon that might have predated the rising HIV prevalence. Apparently, the Table 1. Comparison of locations for sexual partnership in men who have sex with men between two time periods – those infected with HIV in 2000 or before and others in 2001 or after *P < 0.05