Background: Data on the protective effect of additional lubrication of condom among female sex workers (FSW) are controversial. We examined the association between additional lubrication of condom and prevalence of curable STI among FSW, and assessed whether condom consistent use (CCU) modifies this association.
Methods: During an integrated behavioural and biological survey conducted in Benin in March 2012, we collected data on participants’ socio-demographic characteristics and sexual risk behaviours. Genital samples were collected and tested for bacterial STI [Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT)] respectively]. Log-binomial regression was used to model prevalence of NG and/or CT infections in relation to condom lubrication. In addition, the product term between condom lubrication and CCU over the previous 30 days was included in the model to test for effect-measure modification.
Results:Among the 915 FSW included in the analysis, 475 (51.9%) reported additional condom lubrication and 106 (11.7%) had gonococcal and/or chlamydial infections. In multivariate analysis, controlling for age and sex work typology, condom lubrication was significantly associated with lower NG and/or CT prevalence with the adjusted prevalence ratio (APR) = 0.53, 95%CI=0.35 - 0.81 (p= 0.0038). In addition, CCU modified the APR measuring the association between condom lubrication and bacterial STI (p for interaction=0.05): in women with CCU, condom lubrication was significantly associated with lower NG and/or CT prevalence with APR= 0.45, 95% CI=0.26 - 0.76, (p=0.0027), while in those without CCU, it was not (APR= 0.87; 95% CI=0.42 - 1.82, (p=0.7185)).
Conclusions:Our findings suggest that adding extraneous lubricant to condom before use constitutes an added-value to the benefit of condom use in the prevention of STI among FSW. They also suggest that this protective effect would not be achieved unless condom is used consistently. STI prevention interventions should promote both lubrication and consistent use of condom to optimize results.