Obesity, diabetes, and length of time in the United States: Analysis of National Health and Nutrition Examination Survey 1999 to 2012

Obesity prevalence remains high in the United States (US), and is rising in most other countries. This is a repeated cross-sectional study using a nationally representative sample of the National Health and Nutrition Examination Survey 1999 to 2012. Multivariate logistic regression analyses were separately performed for adults (n=37,639) and children/adolescents (n=28,282) to assess the associations between the length of time in the US, and the prevalences of obesity and diabetes. In foreign-born adults, the prevalences of both obesity and diabetes increased with the length of time in the US, and 20 years in the US was associated with significantly higher rates of obesity (adjusted odds ratio [aOR] 2.32, 95% confidence interval [CI] 1.22-4.40, P=0.01) and diabetes (aOR 4.22, 95% CI 1.04-17.08, P=0.04) compared with <1 year in the US. In children/adolescents, obesity prevalence was significantly higher in those born in the US than those who had been in the US for <1 year (aOR 3.15, 95% CI 1.51-6.56, P=0.002). When analyzed by year, obesity prevalence was significantly higher in US-born than in foreign-born adults from 1999 to 2012. On the other hand, the gap in obesity prevalence between US-born and foreign-born children/adolescents decreased from 1999 to 2011 due to a rapid increase in obesity prevalence among the foreign-born population, until there was no significant difference in 2011 to 2012. This study revealed that the risks of obesity and diabetes have increased in foreign-born US residents with time living in the US. However, the obesity gap between US-born and foreign-born populations is closing.