Abstract 129: Effect of Immigration to the US on Prevalence of Hypertension and Obesity in Asians

Abstract

Introduction: In the United States, three fourths of the Asian population growth has been due to immigration. However, the effect of immigration on health of Asian immigrants has not been studied systematically. The goal of this project was to evaluate the effect of immigration on hypertension and obesity prevalence in Far East Asians. Hypothesis : The prevalence of hypertension and obesity is higher in Asians who immigrated to US as compared to Asians residing in the country of birth. Methods: We used the Korean National Health and Nutrition Examination Survey (KNHANES) and the US National Health Interview Survey (NHIS) to compare prevalence of hypertension and obesity in each population. The KNHANES is a national survey conducted by the Korea Institute of Health and Social Affairs with a multistage probability sampling design. The NHIS is an annual public health survey collected in US to monitor the overall health of US population. From NHIS, a subgroup of adults born in Korea and neighboring Far East countries who immigrated to US were compared to adults residing in Korea. In order to conduct a case-control study, Korean immigrants from NHIS were matched with Koreans from KNHANES by age, sex and income level in 1:1 ratio. The prevalence of hypertension and obesity (BMI≥25 kg/m 2 ) was evaluated then in both cohorts. The case-control study was limited to the subjects of 40 years and older. Results: Overall, in the KNHANES adult population 27% reported to have high blood pressure and 34% had BMI≥25 whereas in the NHIS Korean population 30% had hypertension and 37% had obesity. The case-control study based on matching Korean adults from KNHANES and NHIS included 236 adults from each survey who were 40 years and older, 55% were females, 67% belonged to the high income group, and the mean age was 54.4±11.7. In the controls from Korean NHANES, 26% (N=60) reported to have hypertension and 32% (N=76) had a BMI>25 whereas in the matched cases from US NHIS 31% (N=73) had hypertension and 36% (N=86) had BMI>26. The differences in hypertension and obesity prevalence between two groups were statistically significant (P<0.05). Conclusions: The overall prevalence of hypertension and obesity was lower in Koreans residing in the country of birth than in Koreans who immigrated to the United States.