Mobility for sex work and recent experiences of gender-based violence among female sex workers in Iringa, Tanzania: A longitudinal analysis

Female sex workers are highly mobile, which may influence their risk of experiencing physical and sexual violence. However, there remains a paucity of research, particularly longitudinal, from Sub-Saharan Africa exploring mobility and gender-based violence among female sex workers. To address this gap, this study examined the longitudinal relationship between work-related mobility and recent experience of physical or sexual gender-based violence from a client or partner among female sex workers in Iringa, Tanzania. A secondary data analysis was conducted using baseline and 18-month follow-up data from Project Shikamana, a community empowerment-based combination HIV prevention intervention. Responses from 387 female sex workers aged 18 years and older participating in both baseline and follow-up were analyzed. Unadjusted and adjusted Poisson regression models with robust variance estimations, accounting for clustering of female sex workers' responses over time, were fit. Final models adjusted for socio-demographic characteristics and aspects of participants' living situations and work environments. Recent physical or sexual violence from a client or partner was common (baseline: 40%; follow-up: 29%). Twenty-six percent of female sex workers at baseline, and 11% at follow-up, had recently traveled outside of Iringa for sex work. In the final adjusted longitudinal model, female sex workers recently mobile for sex work had a 25% increased risk of any recent experience of physical or sexual gender-based violence when compared with their non-mobile counterparts (adjusted incidence rate ratio: 1.25; 95% CI: 1.03-1.53; p