OBJECTIVE:

To examine the relationship between body mass index (BMI) and metabolic syndrome for Asian Americans and non-Hispanic Whites (NHWs), given that existing evidence shows racial/ethnic heterogeneity exists in how BMI predicts metabolic syndrome.

RESEARCH DESIGN AND METHODS:

Electronic health records of 43,507 primary care patients aged 35 years and older with self-identified race/ethnicity of interest (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese or NHW) were analyzed in a mixed-payer, outpatient-focused health-care organization in the San Francisco Bay Area.

RESULTS:

Metabolic syndrome prevalence is significantly higher in Asians compared with NHWs for every BMI category. For women at the mean age of 55 and BMI of 25  kg  m(-2), the predicted prevalence of metabolic syndrome is 12% for NHW women compared with 30% for Asians; similarly for men, the predicted prevalence of metabolic syndrome is 22% for NHWs compared with 43% of Asians. Compared with NHW women and men with a BMI of 25  kg  m(-2), comparable prevalence of metabolic syndrome was observed at BMI of 19.6  kg  m(-2) for Asian women and 19.9  kg  m(-2) for Asian men. A similar pattern was observed in disaggregated Asian subgroups.

CONCLUSIONS:

In spite of the lower BMI values and lower prevalence of overweight/obesity than NHWs, Asian Americans have higher rates of metabolic syndrome over the range of BMI. Our results indicate that BMI ranges for defining overweight/obesity in Asian populations should be lower than for NHWs.