Van Der Bij, A., Stolte, I., Coutinho, R., & Dukers, N. (2005). Sexually Transmitted Infections, (81(1), 34-37.

Synopsis
At a Municipal Health Service clinic in Amsterdam, HIV and sexually transmitted infection (STI) incidence increased among men who have sex with men (MSM). While HIV increased mostly among MSM age 35 and older, rectal gonorrhea rates increased mainly in younger MSM.

The current study investigated the divergence in STI and HIV trends among HIV-negative MSM age 30 and younger from 1984 until 2002. The study involved 863 MSM enrolled in the Amsterdam Cohort Studies (ACS) from 1984 on who attended at least one of six monthly follow-up ACS visits at which they completed a questionnaire. The survey asked whether participants had experienced episodes of gonorrhea and syphilis, and the men were tested for syphilis and HIV. Annual HIV and STI incidence trends and risk factors were analyzed using Poisson regression.

The mean age of participants was 25 years, and median follow-up time was four years. Trends in HIV and STI incidence were concurrent until 1995, when there was a significant increase in syphilis (0 to 1.4/100 person years) and gonorrhea incidence (1.1 to 6.0/100 person years), but no change in HIV incidence (1.1 and 1.3/100 person years).

"The incidence of syphilis and gonorrhoea has increased among young homosexual men since 1995, while HIV incidence has remained stable," the study authors concluded. "Increasing STI incidence underscores the potential for HIV spread among young homosexual men. However, several years of increasing STIs without HIV, makes the relation between STI incidence and HIV transmission a subject for debate."  

Source
http://sti.bmjjournals.com/cgi/content/full/81/1/34