Body mass index in a US national sample of Asian Americans: effects of nativity, years since immigration and socioeconomic status.

OBJECTIVE: To examine body mass index (BMI) and the proportion overweight and obese among adults age 18-59 in the six largest Asian American ethnic groups (Chinese, Filipino, Asian Indian, Japanese, Korean, Vietnamese), and investigate whether BMI varies by nativity (foreign-vs native-born), years in US, or socioeconomic status. DESIGN: Cross-sectional interview data were pooled from the 1992-1995 National Health Interview Survey (NHIS). SUBJECTS: 254,153 persons aged 18-59 included in the 1992-1995 NHIS. Sample sizes range from 816 to 1940 for each of six Asian American ethnic groups. MEASUREMENTS: Self-reported height and weight used to calculate BMI and classify individuals as overweight (BMI > or = 25 kg/m2) or obese (BMI > or = 30 kg/m2), age, sex, years in the US, household income and household size. RESULTS: For men, the percentage overweight ranges from 17% of Vietnamese to 42% of Japanese, while the total male population is 57% overweight. For women, the percentage overweight ranges from 9% of Vietnamese and Chinese to 25% of Asian Indians, while the total female population is 38% overweight. The percentage of Asian Americans classified as obese is very low. Adjusted for age and ethnicity, the odds ratio for obese is 3.5 for women and 4.0 for men for US-vs foreign-born. Among the foreign-born, more years in the US is associated with higher risk of being overweight or obese. The association between household income for women is similar for US-born Asian Americans and Whites and Blacks, but is much weaker for foreign-born Asian Americans. CONCLUSIONS: While these data find low proportions of Asian Americans overweight at present, they also imply the proportion will increase with more US-born Asian Americans and longer duration in the US.