Cardiometabolic risk factors and obesity: Does it matter whether BMI or waist circumference is the index of obesity?

Abstract

Background: It has been suggested that the cardiometabolic risk associated with excess adiposity is particularly related to central obesity. Objective: The objective was to compare the associations between cardiometabolic risk of apparently healthy individuals and measures of central obesity [waist circumference (WC)] and overall obesity [body mass index (BMI)]. Design: In this cross-sectional, observational study, 492 subjects (306 women and 303 non-Hispanic whites) were classified by BMI (in kg/m2) as normalweight (BMI<25) or overweight/obese (BMI = 25.0-34.9) and as having an abnormal WC (≥80 cm in women and ≥94 cm in men) or a normal WC (<80 cm in women and <94 cm in men). Measurements were also made of the cardiometabolic risk factors age, systolic blood pressure (SBP), and fasting plasma glucose (FPG), triglyceride, and high-density lipoprotein (HDL)-cholesterol concentrations. Associations among cardiometabolic risk factors and BMI and WC were evaluated with Pearson correlations. Results: There was a considerable overlap in the normal and abnormal categories of BMI and WC, and ~81% of the subjects had both an abnormal BMI and WC. In women, BMI and WC correlated with SBP (r = 0.30 and 0.19, respectively), FPG (r = 0.25 and 0.22, respectively), triglycerides (r = 0.17 and 0.20, respectively), and HDL cholesterol (r = 20.23 and 20.20, respectively) (P < 0.01 for all). In men, BMI and WC also correlated with SBP (r = 0.22 and 0.22, respectively), FPG (r = 0.22 and 0.25, respectively), triglycerides (r = 0.21 and 0.18, respectively), and HDL cholesterol (r = 20.20 and 20.13, respectively) [P< 0.05 for all, except for the association of WC with HDL cholesterol (P = 0.08)]. Conclusions: Most individuals with an abnormal BMI also have an abnormal WC. Both indexes of excess adiposity are positively associated with SBP, FPG, and triglycerides and inversely associated with HDL cholesterol. © 2013 American Society for Nutrition.