Differential effect of food security on BMI by birthplace and years of residence in the United States among Mexican American women

BACKGROUND: Although cross-sectional studies have found that female adults in food insecure households have a higher prevalence of overweight/obesity (BMI≥25), few studies have examined whether effects of food security on BMI are different for foreign born compared to US born women. OBJECTIVE: To determine the relationship between food security and overweight/obesity, and whether this relationship varies according to birthplace-US length of residence among Mexican immigrants and US born Mexican American women. METHOD: Using data from the California Health Interview Survey (CHIS) years 2001, 2003, and 2005, prevalence of overweight/obesity according to birthplace was estimated; regression models were fitted that controlled for age, marital status, income, education, birthplace-US length of residence, smoking, physical activity, diabetes, and an interaction term between food security and birthplace-US length of residence was added. Food security was measured as a 2-way categorical variable constructed from the U.S. Household Food Security Module. To avoid collinearity, birthplace and years of residence in the US were combined into a single variable as follows: US born, Foreign born>10 years of residence, and Foreign born<10 years of residence. RESULTS: The relationship between BMI and food security was not statistically significant (p=0.067) after controlling for age, race, marital status, income, education, birthplace, years in the US, smoking, physical activity, and diabetes. We found no evidence of a significant interaction between food security and a combined variable measuring birthplace and years of residence in the US (p=0.183).

DISCUSSION/CONCLUSION: Food security was not significantly associated with BMI among Mexican American women. Pathways other than food insecurity may operate to influence BMI in these groups. Furthermore, the effect of food security on BMI does not seem to vary according to birthplace-US length of residence among Mexican American women. Further studies should examine these relationships among women of other Hispanic ethnicities.