Sexual behaviour and sexually transmitted infections in sexually transmitted infection clinic attendees in the Netherlands, 2007-2011

High annual figures of sexually transmitted infections (STIs) are diagnosed in the Netherlands despite significant efforts to control them. Herein, we analyse trends and determinants of STI diagnoses, co-infections, and sexual risks among visitors of 26 STI clinics between 2007 and 2011. We recorded increased positivity rates of STIs (chlamydia, syphilis, gonorrhoea, and/or HIV) in women and heterosexual men up to 12.6% and 13.4%, respectively, in 2011, while rates in men having sex with men (MSM) were stable but high (18.8%) through the documented years. Younger age, origin from Surinam/Antilles, history of previous STI, multiple partners, or a previous notification are the identified risk factors for an STI in this population. Known HIV-infected men (MSM and heterosexuals) were at highest risk for co-infections (relative rate heterosexual men: 15.6; MSM: 11.6). STI positivity rates remained high (MSM) or increased over time (women and heterosexual men), a fact that highlights the importance of continuing STI prevention. Most importantly, the very high STI co-infection rates among HIV-positive men requires intensified STI reduction strategies to put an end to the vicious circle of re-infection and spread of HIV and other STIs.