The effect of migration on HIV high-risk behaviors among Mexican migrants.

BACKGROUND: Previous studies have shown an association between Mexican migration to the United States and an increased frequency of HIV high-risk behaviors among male Mexican migrants. However, the individual level change in these behaviors after migration has not been quantified. OBJECTIVE: To estimate the change in HIV high-risk behaviors among Mexican migrants after migration to the United States. METHODS: A case-crossover study was embedded in the California-Mexico Epidemiological Surveillance Pilot, a targeted, venue-based, sampling survey. We implemented the study from July to November 2005, studying 458 Mexican migrants at sites in rural and urban areas in Fresno County and San Diego County and directly comparing individual HIV high-risk behaviors before and after migration. RESULTS: After migration, there were increases in the odds of male migrants engaging in sex with a sex worker [odds ratio (OR) = 2.64, P < 0.0001], sex while under the influence of drugs or alcohol (OR = 5.00, P < 0.0001), performing sex work (OR = 6.00, P = 0.070), and sex with a male partner (OR = 13.00, P = 0.001). Those male Mexican migrant subgroups at particularly elevated risk were those in the United States for more than 5 years, those from the youngest age cohort (18-29 years old), or those frequenting high-risk behavior venues and male work venues. CONCLUSIONS: Our results show that Mexican migrant men were significantly more likely to engage in several HIV high-risk behaviors after migration to the United States. However, a smaller proportion of men reported low condom use after migration, indicating increased adoption of some prevention methods. Our results also identified subgroups of Mexican migrants at elevated risk who should be targeted for HIV prevention interventions.