The Effect of Migration on HIV The Effect of Migration on HIV High-risk Behaviors among High-risk Behaviors among

Mexican MigrantsMexican Migrants

Melissa A. SanchezMelissa A. Sanchez11, María T. Hernández, María T. Hernández11, Alicia Vera, Alicia Vera11, , Carlos Magis-RodríguezCarlos Magis-Rodríguez22, Juan D. Ruiz, Juan D. Ruiz33, Michael V. Drake, Michael V. Drake44, George F. Lemp, George F. Lemp11

11California HIV/AIDS Research Program, University of California, California HIV/AIDS Research Program, University of California, Office of the PresidentOffice of the President

22CENSIDA, Secretaria de Salud de MexicoCENSIDA, Secretaria de Salud de Mexico33Office of AIDS, California Department of Public HealthOffice of AIDS, California Department of Public Health

44University of California, IrvineUniversity of California, Irvine

IAC 2008 Mexico CityIAC 2008 Mexico CityTuesday, August 5, 2008Tuesday, August 5, 2008

Mexican Immigrants in Mexican Immigrants in CaliforniaCalifornia

California is home to about 40% of Mexican California is home to about 40% of Mexican Immigrants in the U.S.Immigrants in the U.S.• Over 11 million Mexican immigrants live in the Over 11 million Mexican immigrants live in the

U.S.U.S.• Over 4 million Mexican immigrants live in Over 4 million Mexican immigrants live in

California.California.Source: : U.S. Census Bureau, 2006 American Community Survey

Economic and Economic and social social factors are the factors are the driving driving force for migration force for migration to to California.California.

Migration-related factors such as poverty, Migration-related factors such as poverty, underemployment, substandard housing, underemployment, substandard housing,

isolation, constant mobility, depression, and isolation, constant mobility, depression, and limited access to healthcare contribute to limited access to healthcare contribute to

the vulnerability among Mexican migrants of the vulnerability among Mexican migrants of acquiring HIV while in the U.S.acquiring HIV while in the U.S.

Mexico is Surrounded by Higher Mexico is Surrounded by Higher HIV Prevalences 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

BackgroundBackground

Hypothesis:Hypothesis: The impact of migration from The impact of migration from Mexico to the U.S. leads to increased risk for HIV Mexico to the U.S. leads to increased risk for HIV infection.infection.

Previous studies have identified an association Previous studies have identified an association between Mexican migration to the U.S. and between Mexican migration to the U.S. and increased HIV high-risk behaviors; however, the increased HIV high-risk behaviors; however, the individual level change in these behaviors after individual level change in these behaviors after migration has not been quantified.migration has not been quantified.

Utilizing a crossover study design, we directly Utilizing a crossover study design, we directly

quantified the change in HIV high-risk behaviors quantified the change in HIV high-risk behaviors among Mexican migrants by comparing their among Mexican migrants by comparing their individual behaviors before and after migration. individual behaviors before and after migration.

The California-Mexico Epidemiological The California-Mexico Epidemiological Surveillance Pilot (CMESP): Surveillance Pilot (CMESP):

• Binational collaboration between federal, Binational collaboration between federal, state, and local agencies in Mexico and in state, and local agencies in Mexico and in California. California.

• Combines outreach techniques with sample Combines outreach techniques with sample survey methods to enumerate, sample, and survey methods to enumerate, sample, and estimate HIV high-risk behavior prevalence estimate HIV high-risk behavior prevalence

CMESPCMESP

Target Population: Target Population: Migrants and Recent ImmigrantsMigrants and Recent Immigrants

Inclusion criteria:Inclusion criteria:

Persons born in Mexico that have Persons born in Mexico that have been living/working in the U.S. for been living/working in the U.S. for five years or lessfive years or less

Persons born in Mexico that have Persons born in Mexico that have been living/working in the U.S. for been living/working in the U.S. for more than five years but return to more than five years but return to Mexico at least every 24 monthsMexico at least every 24 months

Persons between the ages of 18-64Persons between the ages of 18-64

CMESP Sampling MethodologyCMESP Sampling Methodology CMESP is a venue-based targeted sample of Mexican migrants living in CMESP is a venue-based targeted sample of Mexican migrants living in

rural and urban areas in the counties of San Diego and Fresno. rural and urban areas in the counties of San Diego and Fresno. Sampling included:Sampling included:

• Identifying low-, moderate-, and high-risk sites for enumeration and Identifying low-, moderate-, and high-risk sites for enumeration and sampling based on key informant interviews and focus groups with sampling based on key informant interviews and focus groups with the target populationthe target population

• Participants were systematically sampled and recruited at each site Participants were systematically sampled and recruited at each site in relative proportion to the volume of eligible migrants in relative proportion to the volume of eligible migrants enumerated at that site.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.

CMESP Recruitment VenuesCMESP Recruitment Venues

• Male Work Venues:Male Work Venues: agricultural work fields, agricultural work fields, male migrant camps, makeshift huts in the hills, male migrant camps, makeshift huts in the hills, and job pick-up locationsand job pick-up locations..

• Bar and Club Venues:Bar and Club Venues: including MSM identified including MSM identified sites.sites.

• Community Venues:Community Venues: where male and female where male and female migrants worked and lived or congregated migrants worked and lived or congregated regularly (e.g., family migrant camps, laundromats, regularly (e.g., family migrant camps, laundromats, parks, adult schools, churches, grocery stores).parks, adult schools, churches, grocery stores).

Study Design and AnalysisStudy Design and Analysis Crossover study designCrossover study design

Collection of a comprehensive range of data on Collection of a comprehensive range of data on high-risk sexual and drug use behaviors prior high-risk sexual and drug use behaviors prior to and after migration created matched-pair to and after migration created matched-pair data for each study participant.data for each study participant.

The strength of this crossover study design is The strength of this crossover study design is that each person serves as his/her own control.that each person serves as his/her own control.

Using exact conditional logistic regression, we Using exact conditional logistic regression, we estimated odds ratios with 95% confidence estimated odds ratios with 95% confidence intervals, controlling for venue type and intervals, controlling for venue type and gender.gender.

Change in Behaviors after Migration for Men (n=364)Change in Behaviors after Migration for Men (n=364)

HIV High-Risk HIV High-Risk BehaviorBehavior

% Prior to % Prior to MigrationMigration

% After % After MigrationMigration

OR (95% CI)OR (95% CI) P P Value*Value*

Sexual partner who Sexual partner who was a sex workerwas a sex worker

18.118.1 29.429.4 2.64 (1.68-4.25)2.64 (1.68-4.25) <.0001<.0001

Sexual relations Sexual relations with a partner while with a partner while under the influence under the influence of drugs or alcoholof drugs or alcohol

24.624.6 41.341.3 5.00 (2.93-8.99)5.00 (2.93-8.99) <.0001<.0001

Exchanged sex for Exchanged sex for money, food, money, food,

shelter, drugs, or shelter, drugs, or protectionprotection

1.41.4 2.72.7 6.00 (0.89-138.97)6.00 (0.89-138.97) .070.070

* Mid-* Mid-pp value value

Change in Behaviors after Migration for Men (n=364)Change in Behaviors after Migration for Men (n=364)

HIV High-Risk HIV High-Risk BehaviorBehavior

% Prior to % Prior to MigrationMigration

% After % After MigrationMigration

OR (95% CI)OR (95% CI) P P Value*Value*

Sexual Partner who Sexual Partner who was malewas male

3.63.6 6.96.9 13.00 (2.28-278.9)13.00 (2.28-278.9) .001.001

Low condom use Low condom use (never, rarely, or (never, rarely, or

sometimes)sometimes)

81.481.4 65.165.1 0.21 (0.10-0.43)0.21 (0.10-0.43) <.0001<.0001

* Mid-* Mid-pp value value

Sexual Partner who was a Sex WorkerSexual Partner who was a Sex WorkerStratified by Venue Type: Men (n=364Stratified by Venue Type: Men (n=364))

VenueVenue % Prior to % Prior to MigrationMigration

% After % After MigrationMigration

OR (95% CI)OR (95% CI) P P Value*Value*

Male Work Sites Male Work Sites (n=200)(n=200)

21.521.5 37.037.0 2.94 (1.69-5.32)2.94 (1.69-5.32) <.0001<.0001

Community Sites Community Sites (n=112)(n=112)

12.512.5 21.421.4 2.67 (1.07-7.43)2.67 (1.07-7.43) .035.035

Bars and Clubs Bars and Clubs (n=52)(n=52)

17.317.3 17.317.3 1.00 (0.17-5.82)1.00 (0.17-5.82) 1.0001.000

* Mid-* Mid-pp value value

Sexual Partner who was MaleSexual Partner who was MaleStratified by Venue Type: Men (n=364)Stratified by Venue Type: Men (n=364)

VenueVenue % Prior to % Prior to MigrationMigration

% After % After MigrationMigration

OR (95% CI)OR (95% CI) P P Value*Value*

Male Work Sites Male Work Sites (n=200)(n=200)

.020.020 0.0150.015 1.00 (0.00-19.00)1.00 (0.00-19.00) .500.500

Community Sites Community Sites (n=112)(n=112)

1.81.8 1.81.8 **** ****

Bars and Clubs Bars and Clubs (n=52)(n=52)

13.513.5 38.538.5 18.26 (3.86-Infty)18.26 (3.86-Infty) .0001.0001

*Mid-*Mid-pp value value**Degenerate conditional distribution**Degenerate conditional distribution

Effect ModifiersEffect Modifiers

Male migrants who have been Male migrants who have been living or working in the U.S. for living or working in the U.S. for over five years.over five years.

The youngest age cohort of male The youngest age cohort of male migrants (18-29 years old)migrants (18-29 years old)

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

ConclusionConclusionThose male migrants identified as being at Those male migrants identified as being at particularly elevated risk include:particularly elevated risk include:

•Those living or working in the U.S. for over 5 Those living or working in the U.S. for over 5 yearsyears•The youngest age cohort (18-29 years old)The youngest age cohort (18-29 years old)•Those frequenting male work sites and bars and Those frequenting male work sites and bars and clubs where clubs where women are infrequently presentwomen are infrequently present

These stratified results suggest targeting HIV These stratified results suggest targeting HIV prevention interventions and HIV-related medical prevention interventions and HIV-related medical care needs to these male subgroups and male-care needs to these male subgroups and male-dominated venues where this hard-to-reach dominated venues where this hard-to-reach population is concentrated.population is concentrated.

Migration’s significant effect on increased HIV high-Migration’s significant effect on increased HIV high-risk behaviorsrisk behaviorsamong male Mexican migrants, specifically, suggests among male Mexican migrants, specifically, suggests that, without that, without intervention, the HIV epidemic may expand among intervention, the HIV epidemic may expand among this population. this population.