Ethnic-immigrant disparities in obesity in the United States: patterns and mechanisms

Ming Wen, University of Utah
Lori Kowaleski-Jones, University of Utah
Jessie X. Fan, University of Utah

Using data from 4,331 respondents age 18-64 from the 2003-2006 National Health and Nutrition Examination Survey (NHANES), we examine the patterns of gender-specific disparities in the risks of obesity and abdominal obesity across six ethnic-immigrant groups: US-born whites, US-born blacks, foreign-born blacks, US-born Hispanics, and foreign-born Hispanics. We also explore whether total caloric intake and total physical activity (PA) are mediators of the observed disparities. Obesity risks are captured by clinically measured body mass index (BMI) and waist circumference. Total PA is objectively measured by accelerometer data. After controlling for socio-demographic and health factors, gender differences of ethnic-immigrant disparities in obesity risks are clearly manifested. Among men, the only group difference in obesity risk found is that US-born whites have higher risk of obesity than foreign-born Hispanics; by contrast, US-born whites have higher risk of abdominal obesity than most of the other groups, making the US-born white the most vulnerable group among men. Among women, US-born whites have lower risk of obesity than US-born blacks but higher risk compared to foreign-born blacks and Hispanics. US-born whites are also at lower risk of abdominal obesity than US-born blacks but at a higher risk compared to foreign-born whites. No other group differences are significant in the multivariate models. The US-born black is definitely the most vulnerable group among women. Nativity plays a salient role in obesity risks. Meanwhile, total caloric intake is not a significant covariate of either obesity outcome and cannot explain any of the observed ethnic-immigrant disparities. Total PA is a significant covariate of both obesity outcomes and can explain some ethnic-immigrant disparities. Taken at the face value, promoting PA is likely a fruitful approach to tackling with weight problems among black women. More studies are warranted to confirm these ethnic-immigrant disparities in obesity risks and elucidate the underlying mechanisms.