A comparative evaluation of waist circumference, waist-to-hip ratio, waist-to-height ratio and body mass index as indicators of impaired glucose tolerance and as risk factors for type-2 diabetes mellitus

Abstract

A number of anthropometric indices is used for evaluation of fat tissue accumulation. It is known, that together with increase of obesity increases prevalence of impaired glucose tolerance (IGT) and diabetes mellitus type 2 (DM 2). The aim of this study was to determine, which of following indices: body mass index (BMI), waist to hip ratio (WHR), waist to height ratio (WHtR) and waist circumference (WC) is the most suitable for the assessment of glucose tolerance disturbances' risk in clinical practice.

Material and methods: The research involved an examination of 1965 people aged > or = 35 years selected from the Lublin town population. Their body mass, height, waist and hip circumferences were measured. Fasting glicaemia and glucose concentration level in the 120th minute after 75 g glucose oral load were determined in full vein blood. DM 2 and IGT were diagnosed according to the 1985 WHO criteria. The evaluation of receiver operating characteristics (ROC) and Pearson's correlation test were used for statistical analysis.

Results: The increase of all the studied indices was correlated with the increase of glicaemia, especially after an oral glucose load. The weakest correlation was shown by WHR. WC showed the strongest correlation with fasting glicaemia (except for men, where closer relationship with BMI was observed). Glicaemia after the load was stronger correlated with BMI and WHtR. A comparison of indices made by the analysis of ROC proved that all of them are characterised by a similar relation with the studied diseases. The indices in question showed significantly weaker relation with IGT than with DM 2. WHtR proved to have the highest diagnostic value in the IGT risk assessment IGT and WC in the assessment of DM 2. Interval estimation demonstrated a presence of statistically significant differences between WHR and other indices in the ROC distribution for DM2. The best cut-off points suggested higher DM 2 risk we found were: BMI - 29,2 kg/m2, WC - 97 cm, WHtR - O,62, WHR - 0,91 for women and 27,9 kg/m2, WC - 99 cm, WHtR - O,57, WHR - 0,97 for men.

Conclusions: All the studied indices have a similar value for DM 2 risk assessment. Waist circumference (WC) is especially noteworthy for the family doctor's practice both because of its high diagnostic precision and exceptional simplicity of its determination. The cut-off points of the studied indices should be differentiated according to sex.