Factors associated with early initiation into sex work and sexually transmitted infections among female sex workers in two Mexico-U.S. border cities

Purpose. To examine correlates of early initiation into sex work and sexually transmitted infections (STIs) among female sex workers (FSWs) in Tijuana and Ciudad Juarez, two Mexican cities on the U.S. border where prostitution is quasi-legal.;Methods. FSWs aged ≥18 years without known HIV infection living in Tijuana and Ciudad Juarez who had recent unprotected sex with clients underwent baseline interviews and testing for syphilis, Chlamydia and gonorrhea. Correlates of early initiation into sex work (age<18) and each infection were identified with logistic regression.;Results. Of 920 FSWs interviewed in Tijuana and Ciudad Juarez, 10% were early initiators into sex work. Median age, age initiation into sex work, and duration in sex work were 32, 26, and 4 years, respectively. Overall, 18% had ever injected drugs, 14% often/always used illegal drugs before/during sex in the past month, 38% had clients who injected drugs in the last 6 months, and 69% reported having clients from the U.S. Prevalence of HIV, active syphilis, Chlamydia, and gonorrhea were 6%, 10%, 13%, and 6%, respectively.;Conclusions. Different pathways for early versus later initiators into sex work are apparent in the Mexico-U.S. border region; which has implications for intervention strategies. Drug-using behaviors were more closely associated with active syphilis, Chlamydia, and gonorrhea than were sexual behaviors. STI eradication programs should focus on subgroups of FSWs and their partners who use and inject drugs, expanding access to sterile syringes, and assisting FSWs with safer-sex negotiation in the context of drug use.;Factors independently associated with early initiation were inhalant use, initiating sex work to pay for alcohol, and history of child abuse. Factors associated with later initiation were less education, migration, and initiating sex work for better pay or to support children. Factors independently associated with active syphilis were having injecting drugs, using illegal drugs before/during sex, and having any U.S. clients. Factors independently associated with Chlamydia were being younger, working in Tijuana versus Ciudad Juarez, and recent methamphetamine injection. Factors independently associated with gonorrhea were working in Tijuana versus Ciudad Juarez, using illegal drugs before or during sex, and having a male sex partner who injected drugs.