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Are the recent increases in sexual risk behavior among older or
younger men who have sex with men? Answer: Both
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Continuing increases in sexual risk behavior, sexually transmitted diseases and HIV incidence among men who have sex with men (MSM) have been reported in San Francisco and other cities in north America and Europe. Two
paradigms can be offered to explain the rise in the epidemic. The first focuses on younger MSM. Coming of age largely after the era of high AIDS mortality, this group has not experienced the full brutality of the epidemic. Moreover, prevention messages may seem outdated to this generation. The second focuses on older MSM. Those who have managed to stay HIV negative may have lowered their guard with the advent of highly active antiretroviral therapy, burnt out on 20 years of prevention messages, or become fatalistic that they, like many of their cohort, will ultimately seroconvert anyway. Moreover, their HIV-positive age peers are now living longer, living better and have also lowered their guard.
We examined serial, cross-sectional surveys of several thousand MSM conducted by the STOP AIDS Project to see whether the recent increase in HIV-related risk behavior has occurred primarily among younger or older MSM. From 1994 to 2001, 5147 younger MSM (10.7%) born in or after 1975 and 23 852 older MSM (49.7%) born in or before 1964 completed the survey. Methods are described in detail elsewhere. In brief, the STOP AIDS Project conducts street-based intercept interviews in diverse gay-oriented venues and events through the course of outreach prevention activities. The one-page questionnaire records demographic information and sexual risk behavior in the past 6 months, including unprotected anal intercourse (UAI), and the number of sexual partners. From 1998 to 2001, the questionnaire included the respondent's self-reported HIV serostatus and knowledge of partners' HIV serostatus.
We tracked trends in four indicators of HIV risk: any UAI, UAI with two or more partners, UAI with at least one partner of unknown HIV serostatus, and UAI with two or more partners of unknown serostatus (Fig. 1). Visual
inspection of the trend lines suggests that younger MSM increased their risk behavior over time at a slightly faster rate than older MSM. In the most extreme example, older MSM started out with a higher level of UAI with two or more partners compared with younger MSM (10.7 versus 8.0%, respectively), but ended up with a lower level (14.3 versus 18.7%, respectively). However, analysis that accounted for potential confounding and interactions between the age of respondents and the year of the survey did not find evidence of a significant differential rate of increase in risk behavior. The Hosmer-Lemeshow goodness of fit tests for all risk models examining the interaction between the age cohort and the year of survey were highly significant (i.e. not a good fit of the data). In other words, the data support increasing risk behavior over time occurring in both older and younger MSM, not predominantly in one or the other. Of note is the
fact that white MSM reported significantly higher levels of risk, adjusting for the year of survey and age compared with other racial/ethnic groups.
As in previous publications, we recognize the limitations of interpreting these data. Subjects are a convenience sample of MSM and data are serial cross-sectional surveys. An ideal analysis would examine behavior change among individuals followed longitudinally. Nonetheless, our earlier reported increase in UAI using the STOP AIDS Project data has been corroborated by increases in sexually transmitted diseases and HIV transmission among MSM in San Francisco. Other strengths of the data are the large sample size and the diversity of venues used for recruitment.
In conclusion, our analysis could be interpreted as lending support to both paradigms operating together: a new generation of young MSM is engaging in higher levels of sexual risk behavior than a few years ago, and the oldelder
generation has recently increased their level of sexual risk. Alternatively, a third paradigm not yet identified may account for the increase in risk observed in both generations.
AIDS 2003; 17(6):942-943
Sanny Y. Chena; Darlene Weideb; Willi McFarlanda. aSan Francisco Department of Public Health, San Francisco, CA, USA; and bThe STOP AIDS Project, San Francisco, CA, USA.
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