摘要：Objectives. We investigated whether Mexican immigration to the United States exerts transnational effects on substance use in Mexico and the United States. Methods. We performed a cross-sectional survey of 2336 Mexican Americans and 2460 Mexicans in 3 Texas border metropolitan areas and their sister cities in Mexico (the US–Mexico Study on Alcohol and Related Conditions, 2011–2013). We collected prevalence and risk factors for alcohol and drug use; Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, alcohol-use disorders; and 2 symptoms (hazardous use and quit or control) of drug use disorder across a continuum of migration experiences in the Mexican and Mexican American populations. Results. Compared with Mexicans with no migrant experience, the adjusted odds ratios for this continuum of migration experiences ranged from 1.10 to 8.85 for 12-month drug use, 1.09 to 5.07 for 12-month alcohol use disorder, and 1.13 to 9.95 for 12-month drug-use disorder. Odds ratios increased with longer exposure to US society. These findings are consistent with those of 3 previous studies. Conclusions. People of Mexican origin have increased prevalence of substance use and disorders with cumulative exposure to US society. During the past 25 years, epidemiological research in the United States has consistently found that alcohol and drug use and disorders of use among Mexican immigrants and Mexican Americans tend to be associated with increasing immersion into US society. 1–8 More recently, transnational effects of migration on substance use in both the United States and Mexico have become apparent. First, in a comparable Mexican population without any migration experience as a reference group, it was found that Mexican immigrants in the United States and US-born persons of Mexican origin exhibited increased risk of alcohol and drug use. 9,10 Second, it was also shown that, in Mexico, substance use of return migrants and families of migrants was also affected by this immigration flow. 11,12 These findings suggest a transnational pattern whereby Mexican immigrants increase their use of substances while in the United States by means of early age at immigration and years living in the United States, 13–15 and transmit, directly and indirectly, substance use behaviors back into Mexico. This conceptualization is intriguing, but the data provided so far are limited to studies either in the United States or in Mexico. The only previous binational study 9 collected data from a wide range of communities in Mexico and the United States and evidence with greater geographic detail is needed to corroborate and extend our understanding. The border regions of Mexico and the United States are particularly important as settings in which the cultures of the 2 countries come into contact and as transit points for migrants moving in both directions. The border region is also filled with contrasts. The US counties are much richer than the Mexican municipalities, but some of the US counties in the border area are among the poorest in the United States. At the same time, some of the Mexican border municipalities are among the richest when compared with national Mexican averages. Research in this region has documented the impact that US nativity, age at immigration, and years living in the United States have in increasing alcohol and drug use and disorders among those of Mexican ancestry living in the US borderland. 8,16–18 On the Mexican side of the border, research generally documented higher prevalence rates for substance use and disorders of use when compared with cities off the border or against national averages. 19 Previous research nevertheless lacks a binational approach—with a common framework and risk factors. Our project, the first simultaneous study that includes the dynamic experiences of contemporary Mexican immigration on both sides of the border, has started to shed new insights on the alleged differences of alcohol and drug use and disorders of use in the US–Mexico border area. 20,21 Our main hypothesis is that with early age of immigration, and increasing time and contact with the US culture, alcohol use, drug use, alcohol use disorders (AUDs) and symptoms of drug use disorder (DUD) will increase along a continuum of immigration experiences in this transnational population. Our main goal is to report the prevalence of, and risk factors for, the occurrence of alcohol use, drug use, AUD, and symptoms of DUD for this population of Mexican ancestry. A second goal is to put these new results in the context of previous findings and to examine the consistency of risk estimates for substance use across the full spectrum of the Mexican immigrant groups.
