Abstract
OBJECTIVE: The impact of migration and health is an important and growing concern worldwide. Recognition that poor health outcomes among migrants are often due to or exacerbated by underlying social determinants (such as employment, living conditions, access to food, and exposure to violence) in the countries of origin, as well as factors related to the acute experiences associated with migration itself, has led to increased awareness that migration itself can be considered a social determinant of health. In North America, in the US-Mexican context in particular, binational research studies focusing on migration have grown substantially in recent years. To date, there has been no formal assessments summarizing the outcomes of this US-Mexico binational research or a distillation of the study designs and topics of study employed to address the unique questions migration/immigration poses. This paper summarizes the literature relevant to Mexico-US migration over an extended time period, organizes this literature by study design methodology and research approach, and provides a discussion of the literature in a broader context of public health research priorities for understanding and improving the health of immigrant populations. MATERIALS AND METHODS: We conducted a literature review of published health literature in PubMed between January, 1999 and February, 2015 representing studies including US and Mexico samples and the title word 'binational'. The summary of the included literature focused on articles that describe in sufficient detail methodological approaches to implementing binational designs. Following a synthesis of the literature, we developed typologies of binational study designs to aid in selecting designs for future research among binational populations. Examples of research designs that reflect different approaches to binational health research as well as topics of focus are presented and discussed. RESULTS: Fifty-nine studies representing three types of study designs were identified: 1) binational parallel studies with two samples using the same instruments (n=39); 2) concurrent studies involving large scale samples from each country combined (n=13); and 3) look-back studies with a focus on research within a linked binational community sample (n=7). The majority of studies used the parallel and concurrent designs and focus on US-Mexico border populations and samples from high migration areas in the US and Mexico. These studies often directly explore the proposed immigrant health advantage and potential biases associated with studies focusing on US-born versus immigrant Hispanics. Look back studies examined communities that were linked directly in the sampling, often through indigenous community ties, and often explored potential health disparities affecting indigenous populations, and take into account social determinants factors. The health issues examined included chronic conditions, along with a wide range of other health issues including, mental health, substance abuse, reproductive health, infectious diseases, environmental health, and use of health care services. CONCLUSION: Binational research between the US and Mexico design contributes to our understanding of migrant health and offers critical insights into the processes affecting health outcomes in the US and Mexico. Future studies of all designs can pay closer attention to the social determinants of health in their approach.