Migration and health: Exposure to U.S. may raise obesity risk (2014-03-30)

Obesity is more prevalent among people of Mexican descent living in the U.S. than it is among the Mexican population.
Immigrants to the U.S. who were born in Mexico are more likely to be obese than people from similar families who remained in Mexico. U.S.-born Mexican-Americans are more likely to be obese than Mexico-born immigrants.

 

 

This study compared the prevalence of obesity among US-born Mexican Americans relative to their first-generation Mexican immigrant counterparts. The study used data from epidemiological surveys in Mexico (the Mexican National Comorbidity Survey [MNCS]) and the United States (the Collaborative Psychiatric Epidemiology Surveys (N=3244 respondents).

The results revealed that the gap between first-generation immigrants and the US-born is one part of a graded increase in obesity associated with migration to the United States. Results indicated that the odds for obesity among U.S.-born Mexican Americans of both sexes were roughly three times higher than for first-generation Mexican immigrants to the U.S.

Results also showed that among Mexicans with no direct migration experience, having a migrant in the immediate family is associated with a higher risk for obesity among women but not for men.
This finding may reflect economic influences on diet, such as cash remittances sent by migrants working in the United States. Given that obesity is a risk factor for the major causes of mortality in the U.S., growing obesity rates among Mexican Americans are a public health and clinical concern.

Past research has found that immigrants to the U.S. are typically healthier in many ways than people in their ethnic groups who were born in the U.S.

In February, one study found that Hispanics born abroad had a much lower risk of stroke than their counterparts who were either born or spent most of their lives in the U.S. (see Reuters Health story of March 7, 2012.)

Data from epidemiological surveys in Mexico (the Mexican National Comorbidity Survey6 [MNCS]) and the United States (the Collaborative Psychiatric Epidemiology Surveys7 [CPES]) were combined (N = 3244 respondents). Obesity was defined as a BMI greater than 30 using self-reported height and weight.

With statistical adjustment for age, marital status, education, and smoking, the odds of obesity among men were higher among the first generation in the United States (odds ratio [OR], 1.66 [95% CI, 1.10-2.52]), the second generation in the United States (OR, 3.38 [95% CI, 1.84-6.20]), and the third generation in the United States (OR, 2.68 [95% CI, 1.48-4.86]), relative to men living in Mexico, with no migrant in family (Figure).

Among women, the adjusted odds of obesity were higher for the first generation in the United States (OR, 2.62 [95% CI, 1.72-4.00]), second generation in the United States (OR, 3.08 [95% CI, 1.81-5.23]), and third generation in the United States (OR, 3.79 [95% CI, 2.19-6.57]) relative to women living in Mexico with no migrant in family.

Among women but not among men, respondents living in Mexico with a family member in the United States were more likely to be obese than those with no migrants in their family (OR, 1.73 [95% CI, 1.14-2.62])

Overall, with a few exceptions, the results showed a trend of increasing obesity as "exposure" to the U.S. grew.

As for why a larger percentage of people may be obese the longer they or their families have been in the U.S., Florez and her colleagues write that one theory centers on the so-called food environment.

For example, a 12-oz bottle of American-made Coca-Cola has 240 calories with 65 g of sugar, whereas Mexican-made Coca-Cola has 150 calories per 12-oz bottle with 39 g of sugar (the former is made from high-fructose corn syrup).

For more information...
Mexico–United States Migration and the Prevalence of Obesity: A Transnational Perspective

MDN