Body mass index and obesity-related metabolic disorders in Taiwanese and US whites and blacks: implications for definitions of overweight and obesity for Asians.
BACKGROUND
Recommendations based on scanty data have been made to lower the body mass index (BMI; in kg/m(2)) cutoff for obesity in Asians.


OBJECTIVE
The goal was to compare relations between BMI and metabolic comorbidity among Asians and US whites and blacks.


METHODS
We compared the prevalence rate, sensitivity, specificity, predictive values, and impact fraction of comorbidities at each BMI level and the BMI-comorbidity relations across ethnic groups by using data from the third National Health and Nutrition Examination Survey and the Nutrition and Health Survey in Taiwan (1993-1996).


RESULTS
For most BMI values, the prevalences of hypertension, diabetes, and hyperuricemia were higher for Taiwanese than for US whites. In addition, increments of BMI corresponded to higher odds ratios in Taiwanese than in US whites for hypertriglyceridemia (P = 0.01) and hypertension (P = 0.075). BMI-comorbidity relations were stronger in Taiwanese than in US blacks for all comorbidities studied. BMIs of 22.5, 26, and 27.5 were the cutoffs with the highest sum of positive and negative predictive value for Taiwanese, US white, and US black men, respectively. The same order was observed for women. For BMIs >27, >85% of Taiwanese, 66% of whites, and 55% of blacks had at least one of the studied comorbidities. However, a cutoff close to the median of the studied population was often found by maximizing sensitivity and specificity. Reducing BMI from >25 to <25 in persons in the United States could eliminate 13% of the obesity comorbidity studied. The corresponding cutoff in Taiwan is slightly <24.


CONCLUSIONS
These data suggest a possible need to set lower BMI cutoffs for Asians, but where to draw the line is a complex issue.
Pan
Wen-Harn
WH
Division of Epidemiology and Public Health, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan. pan@ibms.sinica.edu.tw
Flegal
Katherine M
KM
Chang
Hsing-Yi
HY
Yeh
Wen-Ting
WT
Yeh
Chih-Jung
CJ
Lee
Wen-Chung
WC
D000328:Adult; D017677:Age Distribution; D000368:Aged; D044383:Black People; D015992:Body Mass Index; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D009765:Obesity / Q000453:epidemiology* / Q000378:metabolism; D015995:Prevalence; D017678:Sex Distribution; D013624:Taiwan / Q000453:epidemiology / Q000208:ethnology; D014481:United States / Q000453:epidemiology / Q000208:ethnology; D044465:White People; D001741:Black or African American