Waist circumference and BMI cut-off points to predict risk factors for metabolic syndrome among outpatients in a district hospital

Aye M, Sazali M
Correspondence:Dr Mra Aye, mraaye@hotmail.com

ABSTRACT
Introduction Metabolic syndrome (MS) is a cluster of risk factors that increases the risk of cardiovascular disease and type 2 diabetes mellitus (DM). Waist circumference (WC), a surrogate indicator of abdominal fat mass, is used to measure central obesity associated with increased risk of hypertension, insulin resistance and type 2 DM, whereas body mass index (BMI) is traditionally used to measure somatic obesity. This study aimed to identify the WC and BMI cut-off points to predict the metabolic risk factors for MS and to determine which is a better predictor.
Methods This was a cross-sectional study conducted over a period of six months. The study involved 355 subjects aged 13–91 years. Youden’s index was used to identify the optimal cut-off points.
Results The optimal cut-off point of WC to predict individual metabolic risk in females was 84.5–91.0 cm. The BMI cut-off point to predict hypertension and raised fasting blood sugar was 23.7 kg/m², and that for low level high-density lipoprotein cholesterol was 22.9 kg/m². For males, the corresponding cut-off points were 86.5–91.0 cm for WC and 20.75–25.5 kg/m² for BMI, with corresponding sensitivities and specificities. Area under the curve and the odds of developing individual and ≥ 2 metabolic risk factors for MS were higher for WC than for BMI.
Conclusion WC is a better predictor of metabolic risk factors for developing MS than BMI. Therefore, we propose that metabolic risk factors be screened when WC ≥ 80 cm is found in both genders regardless of BMI.