Waist-to-Height Ratio Outperforms Body Mass Index in Associating with Blood Pressure Parameters:A Cross-Sectional Study

Objective This study aimed to compare the association of general obesity (measured by Body Mass Index [BMI]) and abdominal obesity (measured by Waist-to-Height Ratio [WHtR]) with blood pressure parameters among adults. Methods This cross-sectional study was conducted in 2023 on 87 staff members of Mashhad Medical School (50 women, 37 men; age range: 24–76 years). Anthropometric measurements including height, weight, and waist circumference were recorded, and blood pressure was measured using standard protocols. BMI and WHtR were calculated accordingly. Participants were categorized based on BMI (normal, overweight, obese) and WHtR (abdominal obesity: WHtR ≥ 0.5). Systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were compared across groups using appropriate parametric and non-parametric tests. Linear regression analysis was performed to predict blood pressure based on obesity indices. Results The prevalence of overweight and obesity was 58%. Only 13% of participants had abdominal obesity based on WHtR. Significant differences in SBP were observed across BMI groups (p = 0.042), with post-hoc analysis revealing a significant difference between normal-weight and overweight groups (p = 0.02). However, no significant differences were found in DBP (p = 0.07) or MAP (p = 0.15) across BMI categories. In contrast, WHtR showed significant associations with all three blood pressure measures: SBP (p = 0.02), DBP (p = 0.051), and MAP (p = 0.00). Linear regression analysis revealed a significant association between MAP and WHtR groups (p = 0.022), with a predictive formula of MAP = 82.568 + 4.405 × WHtR, while no significant association was found between MAP and BMI groups (p = 0.053). Conclusion Waist-to-Height Ratio demonstrates a stronger and more comprehensive association with blood pressure parameters compared to Body Mass Index. WHtR was significantly correlated with systolic, diastolic, and mean arterial pressure, whereas BMI was only associated with systolic pressure. These findings support the integration of WHtR into routine clinical screenings as a practical and effective tool for early identification of hypertension risk. Longitudinal studies are warranted to establish causal relationships.