These so called 'swingers' need to be offered more tailored interventions by sexual health services to help encourage safer sexual practices and prevent the spread of sexually transmitted infections (STIs).
Swingers are described as heterosexuals who, as a couple, practise mate swapping or group sex, and/or visit sex clubs for couples.
Recreational drug use is associated with high-risk sexual behaviour or sexually transmitted infections and previous studies on the association between drug use and STI focused on women and on men who have sex with men, but there is little data on swingers, who have recently been classified as an emerging high risk group for STIs.
This group of people are known to engage in high risk sexual behaviour such as having multiple sexual partners, group sex, and unprotected sex, but there is little data on their use of drugs and what impact that has.
Dutch researchers, therefore, set out to assess the prevalence of drug use among swingers and its association with high-risk sexual behaviour and STIs.
They studied 289 people of average age 49, who identified themselves as swingers and who visited a STI clinic from 2009 to 2012 in South Limburg, The Netherlands.
The study participants filled in a self-administered questionnaire on their sexual and drug use behaviour while swinging, over the preceding six months.
The researchers assessed associations between sexual behaviour, drug use and STI diagnoses including Chlamydia trachomatis (CT), Neisseria gonorrhoea (NG), syphilis, HIV and hepatitis B.
Recreational drugs included methylenedioxymethamphetamine (MDMA), gamma hydroxybutyrate (GHB), laughing gas, cannabis, alkyl nitrites (poppers), (meth)amphetamines, cocaine, ketamine (LSD), and lysergic acid.
The results showed that a quarter of the male participants had had sex with male swing partners in the last six months, more than half of the participants of both sexes had had group sex in the same period and half of them did not use condoms.
Half of the respondents reported having six or more sex partners over the preceding six months, and had not used a condom during vaginal sex, but there was no differences in sexual risk behaviour between men and women
Further analysis of the results showed that 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 absence of an association for males could be due to a lack of statistical power to detect an association, said the researchers, but other studies had found there was only a link between sex-related drug use and STIs in women and men who have sex with men, and not in heterosexual men.
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)."