Heterogeneity in the association of acculturation with body mass index and waist circumference among Hispanic and Chinese participants in the Multi-ethnic Study of Atherosclerosis (MESA)

Nativity and years living in the U.S. have been linked to body mass index (BMI) and waist circumference (WC) among immigrants. Few have examined heterogeneity in this relationship. Doing so may inform how social processes that relate to different immigrant integration patterns impact obesity. Using baseline data from 802 Mexican-Americans, 694 Non-Mexican-American Hispanics, and 803 Chinese-Americans aged 45-84 in the Multi-ethnic Study of Atherosclerosis (2000-2002), we investigated whether the association of nativity (U.S. vs. foreign-birth) and years of U.S. residence (<10, ≥ 10 years) with clinically-measured BMI (kg/m2) and WC (cm) varied first by race/ethnicity, then by gender or education within race/ethnic groups. Controlling for age, gender, education, and income, U.S. birth was significantly associated with a higher mean BMI and WC among non-Mexican-American Hispanics (mean differences (95% confidence intervals) (BMI: 2.57 (1.27-3.87); WC: 7.76 (4.35-11.16)), Chinese-Americans (BMI: 1.67 (0.44-2.89); WC: 4.75 (1.10-8.40)), and Mexican-Americans only for BMI (0.95 (0.05-1.84)) (p-interaction=0.01 (WC)). Among the foreign-born, greater time in the U.S. was only significantly associated with higher mean BMI and WC among Mexican-Americans (BMI: 1.80 (0.45-3.14); WC: 3.95 (0.70-7.21)). The association of nativity with BMI/WC varied significantly by education and gender only among non-Mexican-Americans. Specifically, foreign birth was no longer protective against higher BMI/WC among males (p-interaction=0.06) and the less educated (p-interaction=0.02). These results confirm that greater acculturation is related to higher BMI and WC but the strength and presence of this relationship differs by ethnicity, gender, and education. This heterogeneity should be considered in research on health consequences of immigration.