Changes in health selection of obesity among Mexican immigrants: a binational examination

The Weight of Migration: Reconsidering Health Selection and Return Migration among Mexicans

While migration plays a key role in shaping the health of Mexican migrants in the US and those in Mexico, contemporary Mexican migration trends may challenge the health selection and return migration hypotheses, two prevailing assumptions of how migration shapes health. Using data from the Mexican Family Life Survey (2002; 2005), we tested these two hypotheses by comparing the cardiometabolic health profiles of (1) Mexico-US future migrants and nonmigrants and (2) Mexico-US return migrants and nonmigrants. First, we found limited evidence for health selection: the cardiometabolic health of Mexico-US future migrants was not measurably better than the health of their compatriots who did not migrate, although migrants differed demographically from nonmigrants. However, return migrants had higher levels of adiposity compared to those who stayed in Mexico throughout their lives; time spent in the US was also associated with obesity and elevated waist circumference. Differences in physical activity and smoking behavior did not mediate these associations. Our findings suggest positive health selection might not drive the favorable health profiles among recent cohorts of Mexican immigrants in the US. However, the adverse health of return migrants with respect to that of nonmigrants underscores the importance of considering the lived experience of Mexican migrants in the US as an important determinant of their health.

Pregnancy-related weight among immigrant and US-born mothers: The role of nativity, maternal duration of residence, and age at arrival

OBJECTIVES

The goals of this study were to examine the associations between nativity and pregnancy-related weight and to assess the associations between maternal duration of residence and age at arrival in the United States on pregnancy-related weight among immigrants.

METHODS

Using logistic regression and data from the Early Childhood Longitudinal Study-Birth Cohort, we assessed differences in preconception weight and gestational weight gain between US-born and immigrant women (N = 7000). We then analyzed differences in both outcomes by duration of residence among immigrants (n = 1850) and examined whether the identified relationships varied by age at arrival in the United States.

RESULTS

Compared to US-born mothers, immigrants were less likely to be classified as obese prior to pregnancy (odds ratio 0.435, 95% confidence interval, 0.321-0.590) or experience excessive gestational weight gain (odds ratio 0.757, 95% confidence interval, 0.614-0.978). Among the immigrant sub-sample, living in the United States for 10-15 years (odds ratio 2.737, 95% confidence interval, 1.459-5.134) or 16+ years was positively associated with both preconception obesity (odds ratio 2.918, 95% confidence interval, 1.322-6.439) and excessive gestational weight gain (odds ratio 1.683, 95% confidence interval, 1.012-2.797, 16+ years only). There was some evidence that the duration of residence was positively associated with preconception obesity, but only among women who had moved to the United States at age 18 years and older.

CONCLUSION

In sum, while immigrants are less likely than US-born mothers to experience preconception obesity or excessive gestational weight gain, these outcomes vary among the former group by duration of US residence.

Health Profile and Health Care Access of Mexican Migration Flows Traversing the Northern Border of Mexico

BACKGROUND

The health of Latino migrants is most often studied with samples of immigrants settled in the United States or returned migrants in Mexico. We examine health outcomes and health care access of Mexican migrants traversing the Mexican border region to gain a better understanding of migrant health needs as they transition between migration phases.

METHODS

We used data from a 2013 probability survey of migrants from Northbound and Southbound migration flows in Tijuana, Mexico (N=2412). Respondents included Northbound migrants with and without US migration experience, Southbound migrants returning home from the United States or the Mexican border region, and migrants returning to Mexico via deportation. Descriptive statistics and regression models were estimated to characterize and compare their health status, behavioral health, and health care access across migration phases.

RESULTS

Northbound migrants with US migration experience, Southbound migrants from the United States, and deported migrants had worse levels of health insurance, health care utilization, and diabetes than Northbound migrants without US migration experience. Southbound migrants returning from the border reported worse self-rated health and deportees had higher odds of reported substance use compared with Northbound migrants without US migration experience.

CONCLUSIONS

Mexican migrants' health profile and health care access vary significantly across migration flows and generally are worse for migrants with US migration experience. The results add to our understanding of Mexican migrant health along the migration continuum and can inform services in sending, receiving, and intermediate communities.

Health Selectivity and Rural-Urban Migration in China: A Nationwide Multiple Cross-Sectional Study in 2012, 2014, 2016

Background: China is undergoing an unprecedented rural-urban migration, which may deeply influence the health of internal migrants. Previous studies suggested that migrants are a selectively healthier population. This paper examines the evidence for and the changes of health selectivity among Chinese internal migrants. Methods: We use data from the China Labor-force Dynamics Survey (CLDS), a nationally representative survey conducted in 2012, 2014, and 2016, respectively. The health statuses of four groups of research subjects (out-migrants, returned migrants, rural residents, and urban residents) are measured by general health, physical health, and emotional health. Results: By comparing the health status of migrants with that of rural residents, we find supportive evidence for the Healthy Migrant Hypothesis that migrants exhibit better health than rural residents in their hometown. We also add strength to the Salmon Bias Hypothesis that migrants returning to their hometowns are less healthy than those still being outside. However, migrants present worse emotional health in both comparisons. The general and physical health gaps between migrants, rural residents, and returnees widened in all three rounds of the survey, which implies a possibly increasing trend of health selectivity. This study also suggests that bringing family to the destination requires better general and physical health, but not emotional health. Conclusions: Migrants are positively selected on general and physical health. The health selectivity in 2012–2016 is highly likely to increase, which means that there are increasing number of obstacles for migrants to overcome. Family migration’s high requirement for health might also contribute to it. It is urgent to establish and improve primary health care service systems in rural areas in current circumstances.

Investigating Health Selection Within Mexico and Across the US Border

Despite acquiring lower levels of attainment and earnings, Mexican immigrants exhibit favorable health outcomes relative to their native-born counterparts. And while scholars attempt to reconcile this so-called paradoxical relationship with a variety of theoretical and empirical approaches, patterns of selective migration continue to receive considerable attention. The present study contributes to the literature on health selection by extending the healthy migrant hypothesis in a number of ways. First, we rely on a unique combination of data sets to assess whether the healthy are disproportionately more likely to migrate. We use the latest wave of the Mexican Family Life Survey and the 2013 Migrante Study, a survey that is representative of Mexican-born persons who are actively migrating through Tijuana. Pooling these data also allow us to differentiate between internal and US-bound migrants to shed light on their respective health profiles. Results provide modest support for the healthy migrant hypothesis. Although those who report better overall health are more likely to migrate, we find that the presence of certain chronic conditions increases migration risk. Our findings also suggest that internal migrants are healthier than those traveling to the US, though this is largely because those moving within Mexico reflect a younger and more educated population. This study takes an important step in uncovering variation across migrant flows and highlights the importance of the timing at which health is measured in the migration process.

Healthy Eating among Mexican Immigrants: Migration in Childhood and Time in the United States

Past research on immigrant health frequently finds that the duration of time lived in the United States is associated with the erosion of immigrants' health advantages. However, the timing of U.S. migration during the life course is rarely explored. We draw from developmental and sociological perspectives to theorize how migration during childhood may be related to healthy eating among adult immigrants from Mexico. We test these ideas with a mechanism-based age-period-cohort model to disentangle age, age at arrival, and duration of residence. Results show that immigrants who arrived during preschool ages (2-5 years) and school ages (6-11 years) have less healthy diets than adult arrivals (25+ years). After accounting for age at arrival, duration of residence is positively related to healthy eating. Overall, the findings highlight the need to focus more research and policy interventions on child immigrants, who may be particularly susceptible to adopting unhealthy American behaviors during sensitive periods of childhood.

Why does the health of Mexican immigrants deteriorate? New evidence from linked birth records

This study uses a unique dataset linking the birth records of two generations of children born in California and Florida (1970-2009) to analyze the mechanisms behind the generational decline observed in birth outcomes of children of Mexican origin. Calibrating a simple model of intergenerational transmission of birth weight, I show that modest positive selection on health at the time of migration can account for the initial advantage in birth outcomes of second-generation Mexicans. Moreover, accounting for the socioeconomic differences between second-generation Mexicans and white natives and the observed intergenerational correlation in birth weight, the model predicts a greater deterioration than that observed in the data. Using a subset of siblings and holding constant grandmother quasi-fixed effects, I show that the persistence of healthier behaviors among second-generation Mexican mothers can explain more than half of the difference between the model prediction and the observed birth outcomes of third-generation Mexicans.

Smoking selectivity among Mexican immigrants to the United States using binational data, 1999-2012

Mexican immigrants have lower smoking rates than US-born Mexicans, which some scholars attribute to health selection-that individuals who migrate are healthier and have better health behaviors than their non-migrant counterparts. Few studies have examined smoking selectivity using binational data and none have assessed whether selectivity remains constant over time. This study combined binational data from the US and Mexico to examine: 1) the extent to which recent Mexican immigrants (<10years) in the US are selected with regard to cigarette smoking compared to non-migrants in Mexico, and 2) whether smoking selectivity varied between 2000 and 2012-a period of declining tobacco use in Mexico and the US. We combined repeated cross-sectional US data (n=10.901) on adult (ages 20-64) Mexican immigrants and US-born Mexicans from the 1999/2000 and 2011/2012 National Health Interview Survey, and repeated cross-sectional Mexican data on non-migrants (n=67.188) from the 2000 Encuesta Nacional de Salud and 2012 Encuesta Nacional de Salud y Nutrición. Multinomial logistic regressions, stratified by gender, predicted smoking status (current, former, never) by migration status. At both time points, we found lower overall smoking prevalence among recent US immigrants compared to non-migrants for both genders. Moreover, from the regression analyses, smoking selectivity remained constant between 2000 and 2012 among men, but increased among women. These findings suggest that Mexican immigrants are indeed selected on smoking compared to their non-migrating counterparts, but that selectivity is subject to smoking conditions in the sending countries and may not remain constant over time.

An examination of health selection among U.S. immigrants using multi-national data

While migrants are widely believed to be positively selected on health, there has been very little empirical exploration of the actual health differential between migrants and non-migrants. This paper explored: 1) the extent of health selection by comparing US immigrants from 19 sending countries to their non-migrating counterparts still residing in the countries of origin; 2) country-level correlates of health selection; and 3) whether country-level health selection accounted for differences in self-rated health between immigrants and US-born Whites. We combined nationally-representative international data with data from US immigrants from the 2003-2007 Current Population Survey. The health selectivity measure was the Net Difference Index (NDI), which compares the distribution of self-rated health between migrants and non-migrants. We calculated Spearman correlation and bivariate regression coefficients between the NDI and economic, health, distance, and migration characteristics of the sending countries. We used generalized estimating equation models to examine the association between country-level health selection and immigrants' current self-rated health. We found immigrants from South America to show the most positive health selection. Health selection was significantly correlated with visa mode of entry, where family networks decrease, but work-related networks increase health selection. There was little evidence that country-level health selection explained differences in the self-rated health of US immigrants relative to US-born Whites. Our findings do not support the idea that country-level health selection underlies the "healthy immigrant effect".

Generational status, neighborhood context, and mother-child resemblance in dietary quality in Mexican-origin families

Children of immigrants in the United States often grow up in very different nutrition environments than their parents. As a result, parent-child concordance in diet may be particularly weak in immigrant families. Yet, little is known about parent-child dietary resemblance in immigrant families and how local contexts shape it. This study uses data from the 1999/2000-2009/2010 Continuous National Health and Nutrition Examination Survey to examine mother-child resemblance in dietary quality in Mexican-origin families in the United States. We investigate how immigrant generational status and neighborhood context shape the association between mothers' and children's dietary quality. We find that mother-child resemblance in dietary quality is weaker for first-generation children relative to third-generation children. However, residence in an immigrant enclave strengthens the mother-child association in dietary quality for first-generation children. Findings offer a unique within-family perspective of immigrant health. Results suggest that the healthy eating advantage of Mexican immigrant mothers may not be sustained across family generations and that Mexican immigrant mothers may face unique challenges in promoting healthy eating among their children.