A quarter of the male participants had had sex with male swing partners over the past six months. More than half of all participants had participated in group sex, and half of them did not use condoms.
Half of all respondents had six or more sex partners during the previous six months, and had not used a condom during vaginal sex.
Overall, the prevalence of Chlamydia and/or gonorrhoea was 13% but no other STIs were observed.
More than three quarters (79%) of swingers reported recreational drug use (including alcohol and use of erectile dysfunction drugs); while almost half (46%) of them reported multiple drug use.
Recreational drug use excluding alcohol and erectile dysfunction drugs (reported by 48%) was linked to high-risk behaviours in men and women while drug use was only independently associated with STIs in female swingers, especially those who practiced group sex.
The researchers concluded: “Drug-using populations are a target for interventions that address the practice of safer sex along with secondary prevention of drug use.
“By dealing with all these items properly, more tailored prevention and enhanced STI screening are likely to produce gains for both individuals and the population (reduced STI burden).”