Dramatic Increases in Obesity and Overweight Prevalence among Ethnic-Immigrant and Social Class Groups in the United States, 1991-2006

This study examined trends in obesity and overweight prevalence among 33 immigrant groups, stratified by race/ethnicity and length of immigration, and among detailed education, occupation, and income groups from 1991-2006. Using temporal micro-data from the 1991-2006 National Health Interview Surveys, both observed differentials in obesity and overweight and differentials, adjusted for physical activity and several sociodemographic variables, were analyzed using disparity indices and multivariate logistic regression. During 1991-2006, the obesity prevalence for US-born adults aged 18+ increased from 14% to 27%, while the prevalence for immigrants increased at a slower rate from 9% to 17%. Overall, obesity differentials between US-born and immigrants (differentiated by duration of residence in the US) increased two-fold during the study period. While immigrants in each ethnic group and time period had lower obesity prevalence than the US-born, the immigrants' risk of obesity increased with increasing duration of residence. Obesity prevalence in 2001-2006 ranged from <6% for recent Chinese, Asian Indian, and Filipino immigrants to >31% for US-born blacks and Mexicans, and US-born and long-term Puerto Rican immigrants. Although higher obesity prevalence was observed for lower education, income, and occupation levels in each period, socioeconomic gradients in obesity decreased over time because of more rapid increases in obesity in higher socioeconomic groups. Immigrants, who are an important and growing segment of the US population, are expected to have a substantial impact on the future obesity trends. If immigrants had the same prevalence as the US-born, the current obesity crisis in America would be much worse.