The relationship of illicit drug use to HIV-infection among commercial sex workers in the city of Santos, São Paulo, Brazil

Objective: To assess the role of illicit drug use as a risk factor of HIV infection among female commercial sex workers (CSWs) in the city of Santos, Brazil. Design: Cross-sectional survey of 697 chain-referred CSWs. Methodology: The study included information on social-demographic characteristics, sexual practices and use of illicit drugs. Blood samples were tested for HIV. Associations between the response variable and drug-related variables, controlling for potential confounders, were assessed through multiple logistic regression procedures. Results: The univariate analyses for all drug-related variables evidenced that ‘use of injecting drugs’ (odds-ratios (OR)=10.9) and ‘use of crack in the previous month’ (OR=9.0), were the two variables most highly associated to the outcome. The multivariate analysis emphasized the role of crack use, the first variable included in the stepwise procedure (adjusted OR=5.3, P=0.0001). Other relevant predictors were ‘educational level’ (P=0.0003), ‘practice of anal intercourse with customers’ (P=0.0031), ‘use of injecting drugs’ (adjusted OR=3.1, P=0.0647), ‘age at first intercourse’ (P=0.0188) and ‘age’ (P=0.0175). Additional multivariate results showed that crack-users tend to use other drugs simultaneously, to agree more frequently to have unprotected sex and to earn a significantly smaller payment per sexual encounter than crack non-users. Conclusions: The analysis showed the vulnerability of CSWs in relation to drug use, lack of education and unprotected sex. These findings highlight the need for preventive programs focused on the general use of drugs in this population as well as efforts to help CSWs to acquire educational and professional skills.