【摘要】  Background: The addition of waist circumference (WC) to body mass index (BMI; in kg/m 2 ) predicts a greater variance in health risk than does BMI alone; however, whether the reverse is true is not known.

Objective: We evaluated whether BMI adds to the predictive power of WC in assessing obesity-related comorbidity.

Design: Subjects were 14 924 adult participants in the third National Health and Nutrition Examination Survey, grouped into categories of BMI and WC in accordance with the National Institutes of Health cutoffs. Odds ratios for hypertension, dyslipidemia, and the metabolic syndrome were compared for overweight and class I obese BMI categories and the normal-weight category before and after adjustment for WC. BMI and WC were also included in the same regression model as continuous variables for prediction of the metabolic disorders.

Results: With few exceptions, overweight and obese subjects were more likely to have hypertension, dyslipidemia, and the metabolic syndrome than were normal-weight subjects. After adjustment for WC category (normal or high), the odds of comorbidity, although attenuated, remained higher in overweight and obese subjects than in normal-weight subjects. However, after adjustment for WC as a continuous variable, the likelihood of hypertension, dyslipidemia, and the metabolic syndrome was similar in all groups. When WC and BMI were used as continuous variables in the same regression model, WC alone was a significant predictor of comorbidity.

Conclusions: WC, and not BMI, explains obesity-related health risk. Thus, for a given WC value, overweight and obese persons and normal-weight persons have comparable health risks. However, when WC is dichotomized as normal or high, BMI remains a significant predictor of health risk.

【关键词】  Abdominal obesity metabolic syndrome hypertension dyslipidemia

INTRODUCTION

It has long been recognized that body mass index (BMI; in kg/m 2 ) is a predictor of the morbidity and mortality that are due to numerous chronic diseases, including type 2 diabetes, cardiovascular disease (CVD), and stroke ( 1, 2 ). In addition, it has been established that abdominal obesity, assessed by waist circumference (WC), predicts obesity-related health risk ( 1 - 4 ), and the weighted evidence indicates that WC coupled with BMI predicts health risk better than does BMI alone ( 3, 5 - 7 ). In fact, recent findings indicate that WC is a stronger marker of health risk than is BMI ( 4 ). The utility of BMI and WC in predicting obesity-related health risk has been recognized by the National Heart, Lung, and Blood Institute of the National Institutes of Health (NIH; 2 ). The NIH guidelines indicate that the health risk increases in a graded fashion when moving from the normal-weight through obese BMI categories, and that within each BMI category men and women with high WC values are at a greater health risk than are those with normal WC values ( 2 ). Thus, it is assumed that BMI and