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.