Sexual Violence and HIV Infection Associated With Adolescent vs Adult Entry Into the Sex Trade in Mexico

Adolescents migrating from Central America and Mexico to the United States are at risk for being trafficked into the sex industry in Mexico’s northern border cities.¹ Research from other regions indicates that those entering the sex trade as adolescents (vs as adults) are more likely to experience sexual violence and human immunodeficiency virus (HIV) risk during initiation to the sex trade² and to become infected with HIV.³

Apart from 1 study among injection drug users,⁴ no research exists on the prevalence of minors in the sex industry in Latin America or their subsequent risk for violence and HIV infection.

Between March 2013 and January 2014, female sex workers aged 18 years or older were recruited from Tijuana and Ciudad Juarez, Mexico, via time-location sampling, a method used to simulate random-cluster sampling for studies of hard-to-reach populations.⁵ Indoor and street sex work venues were randomly sampled based on mapping of all venues, with probability of selection proportional to venue size. Of 200 venues identified, 25 did not permit recruitment; venue type did not differ based on permission for recruitment.

Confidential computer-assisted surveys were completed to assess prevalence of adolescent (ages 16-17 years) and early adolescent (ages <16 years) entry to the sex trade and associations of age at entry with violence to force commercial sex, high-client volume (>10 clients/day), and no condom use during the initial 30 days after entry.

Multivariable logistic regression analyses were adjusted for current age, education, city, and marital and migration status at entry. Modeling for HIV infection (serologically assessed) based on age at sex trade entry (<18 years vs ≥18 years to conserve power given small numbers of HIV cases) was adjusted for current age, recent condom use, and lifetime injection drug use.

Analyses were conducted using SAS version 9.4 (SAS Institute Inc). Two-sided tests with P values < .05 were considered statistically significant. Participants provided written informed consent and received $20 US, HIV counseling, and treatment referrals.

Protocols were approved by the University of California, El Colegio de la Frontera Norte, and Universidad Autonoma de Ciudad Juarez.

Of 1041 individuals screened, 614 were eligible and 603 participated (98.2% cooperation rate). The mean (SD) age was 34.3 (10.4) years (Table 1); 25.4% reported entering the sex trade before the age of 18 years and 11.8% reported entry before the age of 16 years.

Compared with those entering sex work as adults, those entering the sex trade as adolescents were more likely to report experiencing violence to force commercial sex (19.7% among those aged <16 years vs 8.7% among adults; adjusted odds ratio [AOR], 2.5 [95% CI, 1.2-5.2]; P = .01), high client volume (21.1% for <16 years vs 9.6% for adults; AOR, 2.4 [95% CI, 1.2-5.0]; P = .02) (19.5% for 16-17 years vs 9.6% for adults; AOR, 2.4 [95% CI, 1.3-4.6]; P = .007), and never use of condoms with clients (35.2% for <16 years vs 8.0% for adults; AOR, 6.6 [95% CI, 3.3-13.2]; P < .001) during their first 30 days in the sex industry (Table 2).

Those reporting entering the sex trade as adolescents were more likely to be infected with HIV compared with those entering as adults (5.9% [9/153] for age <18 years vs 1.6% [7/450] for adults; AOR, 3.1 [95% CI, 1.1-9.3]; P = .04).

More than 1 in 4 female sex workers in these northern Mexican cities reported entering the sex trade as minors. Entering the sex trade as an adolescent vs as an adult was associated with a greater risk for HIV infection, which may relate to elevated risks for violence to force participation in commercial sex, higher numbers of clients, and condom nonuse during initiation to the sex industry. Efforts to effectively protect adolescents vulnerable to sex trade entry and assist adolescents in the sex industry are needed.

Study limitations include potential recall bias in retrospective reporting, and such bias differing based on longer duration of sex work; to address this concern, adjusted models included both age at entry and current age. Although consistent with studies of sex workers in other regions,³ current findings may not generalize to other sex worker populations.

Corresponding Author: Jay G. Silverman, PhD, Center on Gender Equity and Health, University of California–San Diego, 9500 Gilman Dr, La Jolla, CA 92093 (jgsilverman@ucsd.edu).

Author Contributions: Dr Silverman had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Silverman, Goldenberg, Magis-Rodriguez, Raj.

Acquisition, analysis, or interpretation of data: Silverman, Servin, Goldenberg, Ritter, Brouwer.

Drafting of the manuscript: Silverman, Servin, Ritter.

Critical revision of the manuscript for important intellectual content: Silverman, Goldenberg, Magis-Rodriguez, Ritter, Raj, Brouwer.

Statistical analysis: Silverman, Ritter.

Obtained funding: Silverman, Goldenberg, Brouwer.

Administrative, technical, or material support: Silverman, Servin, Goldenberg, Brouwer.

Study supervision: Silverman, Magis-Rodriguez.

Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.

Funding/Support: The study was supported via funding from the National Institute on Drug Abuse (grant R01DA033194 awarded to Dr Silverman and grant R01DA028692 awarded to Dr Brouwer) and the University of California–San Diego AIDS Research Institute via the National Institute of Allergy and Infectious Diseases (grant P30A136214).

Role of the Funder/Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: We thank Leah Gordon, MPH, and Sabrina Boyce, MPH, for contributing to the collection and analysis of the data and revision of the manuscript. Both were compensated as employees of the University of California–San Diego School of Medicine. We also thank Hugo Staines Orozco, MD (Universidad Autónoma de Ciudad Juarez), and Gustavo Martinez Mendizábal, MD (Federación Mexicana de Asociaciones Privadas), who provided assistance with data collection. Neither received compensation for their contributions.