Sexually transmissible infections and sexual risk behaviour among deployed, ship-assigned USA Navy and Marine Corps personnel.

Unlabelled: Background Data show sexually transmissible infection (STI) diagnoses in USA military personnel engaging in unprotected sex are higher during deployment than before or after. We examined sexual risk behaviour, same-sex contact, mixed sex partnerships (both casual and committed partners) and STIs among ship-assigned USA Navy and Marine Corps personnel to assess increased risk.

Methods: Data on sexual risk behaviour, partner type, gender, and healthcare provider-diagnosed STIs were collected longitudinally (2012-14) among sexually active personnel during deployment. Descriptive and bivariate data stratified by sex, STIs, and partner types were analysed using χ2 and t-tests, with statistical significance defined as P < 0.05.

Results: The final sample (n = 634) included 452 men (71%) and 182 women (29%). STI prevalence among males was 8% (n = 36); men who have sex with men (MSM) accounted for 25% of total STIs, and 43% of MSM reported an STI. Among all reporting STIs, 29% reported occasional partners, service member partners (15%) and non-condom use (16%). The highest proportions of non-condom use (71%), alcohol before sex (82%), and same-sex partners (67%) were reported by participants with mixed sex partners; 69% of these reported service member partners.

Conclusions: Personnel with mixed partners reported high proportions of sexual risk behaviour. MSM accounted for 9% of the total population, but 25% of all STIs. As the majority of those with mixed partners and MSM also reported service member sex partners, safer sex education and prompt STI identification/treatment among these groups could reduce STI transmission among military personnel.