Daily activity spaces and drug use among female sex workers living with HIV in the Dominican Republic.

The purpose of this study was to explore the daily activity spaces of female sex workers living with HIV in the Dominican Republic and assess the relationship between activity path and location-based risk exposure measures and daily drug use. The study employed a micro-longitudinal observational study design using an innovative 7-day travel diary to capture daily activity routes and a 7-day mobile health (mHealth) daily diary to collect daily substance use behaviors among 51 female sex workers. To estimate between-subject variability, a series of crude and adjusted modified log-Poisson repeated measures regression models with generalized estimating equations, clustering by individual with a compound symmetry working correlation structure were fit to estimate the relative risks and 95% confidence intervals. Controlling for individual level factors, findings showed that female sex workers exposed to a higher number of risk outlets (e.g., liquor stores, bars, hotels, nightclubs, brothels, etc.) within 200 and 100-meters of sex work locations were at an increased risk of daily drug use (RR: 1.03, 95%CI: 1.01, 1.05, RR: 1.05, 95%CI: 1.01, 1.09). No association was detected between activity path exposure and daily drug use. These findings illustrate the importance of moving beyond static residential neighborhood boundaries for measuring risk exposures and highlight the significant role that daily work environments have on drug harms among a highly stigmatized and vulnerable population.