1. The Effect of Migration on HIV High-risk Behaviors among Mexican Migrants Melissa A. Sanchez 1, María T. Hernández 1, Alicia Vera 1, Carlos Magis-Rodríguez 2, Juan D. Ruiz 3, Michael V. Drake 4, George F. Lemp 1 1 California HIV/AIDS Research Program, University of California, Office of the President 2 CENSIDA, Secretaria de Salud de Mexico 3 Office of AIDS, California Department of Public Health 4 University of California, Irvine IAC 2008 Mexico City Tuesday, August 5, 2008

2. Mexican Immigrants in California California is home to about 40% of Mexican Immigrants in the U.S. California is home to about 40% of Mexican Immigrants in the U.S. Over 11 million Mexican immigrants live in the U.S.Over 11 million Mexican immigrants live in the U.S. Over 4 million Mexican immigrants live in California.Over 4 million Mexican immigrants live in California. Source: : U.S. Census Bureau, 2006 American Community Survey Economic and social Economic and social factors are the driving factors are the driving force for migration to force for migration to California. California.

3. Migration-related factors such as poverty, underemployment, substandard housing, isolation, constant mobility, depression, and limited access to healthcare contribute to the vulnerability among Mexican migrants of acquiring HIV while in the U.S.

4. Mexico is Surrounded by Higher HIV Prevalences Guatemala, 1.0% Belice, 2.0% Honduras, 1.6% El Salvador, 0.6% 0.6% 0.3% Fuente: ONUSIDA. Informe sobre la epidemia mundial de VIH/SIDA 2002. Prevalencia por cada 100 personas de 15-49 años

5. Background Hypothesis: The impact of migration from Mexico to the U.S. leads to increased risk for HIV infection. Hypothesis: The impact of migration from Mexico to the U.S. leads to increased risk for HIV infection. Previous studies have identified an association between Mexican migration to the U.S. and increased HIV high- risk behaviors; however, the individual level change in these behaviors after migration has not been quantified. Previous studies have identified an association between Mexican migration to the U.S. and increased HIV high- risk behaviors; however, the individual level change in these behaviors after migration has not been quantified. Utilizing a crossover study design, we directly quantified the change in HIV high-risk behaviors among Mexican migrants by comparing their individual behaviors before and after migration. Utilizing a crossover study design, we directly quantified the change in HIV high-risk behaviors among Mexican migrants by comparing their individual behaviors before and after migration.

6. The California-Mexico Epidemiological Surveillance Pilot (CMESP): The California-Mexico Epidemiological Surveillance Pilot (CMESP): Binational collaboration between federal, state, and local agencies in Mexico and in California.Binational collaboration between federal, state, and local agencies in Mexico and in California. Combines outreach techniques with sample survey methods to enumerate, sample, and estimate HIV high-risk behavior prevalenceCombines outreach techniques with sample survey methods to enumerate, sample, and estimate HIV high-risk behavior prevalence CMESP

7. Target Population: Migrants and Recent Immigrants Inclusion criteria: Persons born in Mexico that have been living/working in the U.S. for five years or less Persons born in Mexico that have been living/working in the U.S. for five years or less Persons born in Mexico that have been living/working in the U.S. for more than five years but return to Mexico at least every 24 months Persons born in Mexico that have been living/working in the U.S. for more than five years but return to Mexico at least every 24 months Persons between the ages of 18-64 Persons between the ages of 18-64

8. CMESP Sampling Methodology CMESP is a venue-based targeted sample of Mexican migrants living in rural and urban areas in the counties of San Diego and Fresno. Sampling included: CMESP is a venue-based targeted sample of Mexican migrants living in rural and urban areas in the counties of San Diego and Fresno. Sampling included: Identifying low-, moderate-, and high-risk sites for enumeration and sampling based on key informant interviews and focus groups with the target populationIdentifying low-, moderate-, and high-risk sites for enumeration and sampling based on key informant interviews and focus groups with the target population Participants were systematically sampled and recruited at each site in relative proportion to the volume of eligible migrants enumerated at that site.Participants were systematically sampled and recruited at each site in relative proportion to the volume of eligible migrants enumerated at that site. 35-minute standardized questionnaire (refusal rate ~25%)35-minute standardized questionnaire (refusal rate ~25%) Sampling was conducted July-November 2005.Sampling was conducted July-November 2005. The sampling frame was dynamic, consisting of 36 sites.The sampling frame was dynamic, consisting of 36 sites. 458 Mexican migrants were sampled.458 Mexican migrants were sampled.

9. CMESP Recruitment Venues Male Work Venues: agricultural work fields, male migrant camps, makeshift huts in the hills, and job pick- up locations.Male Work Venues: agricultural work fields, male migrant camps, makeshift huts in the hills, and job pick- up locations. Bar and Club Venues: including MSM identified sites.Bar and Club Venues: including MSM identified sites. Community Venues: where male and female migrants worked and lived or congregated regularly (e.g., family migrant camps, laundromats, parks, adult schools, churches, grocery stores).Community Venues: where male and female migrants worked and lived or congregated regularly (e.g., family migrant camps, laundromats, parks, adult schools, churches, grocery stores).

11. Study Design and Analysis Crossover study design Crossover study design Collection of a comprehensive range of data on high- risk sexual and drug use behaviors prior to and after migration created matched-pair data for each study participant. Collection of a comprehensive range of data on high- risk sexual and drug use behaviors prior to and after migration created matched-pair data for each study participant. The strength of this crossover study design is that each person serves as his/her own control. The strength of this crossover study design is that each person serves as his/her own control. Using exact conditional logistic regression, we estimated odds ratios with 95% confidence intervals, controlling for venue type and gender. Using exact conditional logistic regression, we estimated odds ratios with 95% confidence intervals, controlling for venue type and gender.

12. Change in Behaviors after Migration for Men (n=364) HIV High-Risk Behavior % Prior to Migration % After Migration OR (95% CI) P Value* Sexual partner who was a sex worker 18.129.4 2.64 (1.68-4.25) <.0001 Sexual relations with a partner while under the influence of drugs or alcohol 24.641.3 5.00 (2.93-8.99) <.0001 Exchanged sex for money, food, shelter, drugs, or protection 1.42.7 6.00 (0.89-138.97).070 * Mid-p value

13. Change in Behaviors after Migration for Men (n=364) HIV High-Risk Behavior % Prior to Migration % After Migration OR (95% CI) P Value* Sexual Partner who was male 3.66.9 13.00 (2.28-278.9).001 Low condom use (never, rarely, or sometimes) 81.465.1 0.21 (0.10-0.43) <.0001 * Mid-p value

14. Sexual Partner who was a Sex Worker Stratified by Venue Type: Men (n=364 ) Venue % Prior to Migration % After Migration OR (95% CI) P Value* Male Work Sites (n=200) 21.537.0 2.94 (1.69-5.32) <.0001 Community Sites (n=112) 12.521.4 2.67 (1.07-7.43).035 Bars and Clubs (n=52) 17.317.3 1.00 (0.17-5.82) 1.000 * Mid-p value

15. Sexual Partner who was Male Stratified by Venue Type: Men (n=364) Venue % Prior to Migration % After Migration OR (95% CI) P Value* Male Work Sites (n=200).0200.015 1.00 (0.00-19.00).500 Community Sites (n=112) 1.81.8**** Bars and Clubs (n=52) 13.538.5 18.26 (3.86-Infty).0001 *Mid-p value **Degenerate conditional distribution

16. Effect Modifiers Male migrants who have been living or working in the U.S. for over five years. Male migrants who have been living or working in the U.S. for over five years. The youngest age cohort of male migrants (18-29 years old) The youngest age cohort of male migrants (18-29 years old)

17. Conclusion Though results indicate a significant decrease in the number of male migrants reporting low condom use, more notably, results indicate a significant increase in the number of male migrants adopting HIV high-risk behaviors after migration related to sex with a sex worker, sex while under the influence of drugs or alcohol, sex work, and having sex with a male partner.

18. Conclusion Those male migrants identified as being at particularly elevated risk include: Those living or working in the U.S. for over 5 yearsThose living or working in the U.S. for over 5 years The youngest age cohort (18-29 years old)The youngest age cohort (18-29 years old) Those frequenting male work sites and bars and clubs where women are infrequently presentThose frequenting male work sites and bars and clubs where women are infrequently present These stratified results suggest targeting HIV prevention interventions and HIV-related medical care needs to these male subgroups and male- dominated venues where this hard-to-reach population is concentrated. Migration’s significant effect on increased HIV high-risk behaviors among male Mexican migrants, specifically, suggests that, without intervention, the HIV epidemic may expand among this population.