BMI vs. waist circumference for identifying vascular risk

Area of Science:

• Cardiology
• Public Health
• Epidemiology

Background:

• Current guidelines recommend both Body Mass Index (BMI) and waist circumference (WC) for assessing vascular risk in individuals with overweight BMI (25.0–34.9 kg/m²).
• The independent prognostic utility of WC compared to BMI in predicting adverse vascular events requires further investigation.

Purpose of the Study:

• To investigate the relative contributions of BMI and WC in identifying the risk of adverse vascular events.
• To assess the incremental prognostic utility of WC for predicting cardiovascular disease (CVD) risk across different BMI categories.
• To compare the predictive utility of BMI and WC separately for CVD risk.

Main Methods:

• Analysis of 4,195 person-examinations from the Framingham Study (53% women).
• Utilized pooled logistic regression to evaluate the prognostic value of WC and BMI.
• Assessed CVD event risk prediction across normal (<25 kg/m²), overweight (25 to <30 kg/m²), and obese (≥30 kg/m²) BMI categories over 16 years of follow-up.

Main Results:

• In overweight women, increased WC was an independent predictor of CVD incidence (OR 1.86 per SD increment, P=0.04).
• WC did not independently predict CVD incidence in overweight men, normal weight, or obese individuals.
• The predictive performance (c-statistics) of BMI and WC models for CVD risk was nearly identical when analyzed separately.

Conclusions:

• Waist circumference measurement aids in identifying vascular risk specifically among overweight women.
• WC does not substantially add to vascular event risk prediction in normal weight or obese women and men.
• BMI and WC have comparable predictive utility for cardiovascular events when considered independently.