Cut-off points of waist circumference and body mass index for detecting diabetes, hypercholesterolemia and hypertension according to National Non-Communicable Disease Risk Factors Surveillance in Iran

Introduction: The cut-off points of waist circumference and body mass index (BMI) are varied according to different races. There is a dearth of information on these indices especially in Iranian adults. We sought to estimate the cut-off points of waist circumference and BMI for detecting diabetes, hypercholesterolemia, and hypertension. Material and methods: The data were gathered by the First Iranian Non-Communicable Disease Survey in 2005. In total, 70,981 participants between 25 and 64 years of old were selected via random multistage cluster sampling. Receiver operating characteristic curves were used to show the cut-off points of waist circumference and BMI for detecting diabetes, hypercholesterolemia, and hypertension. The maximum value the sum of sensitivity and specificity indicated the cut-off point. Results: The cut-off points of waist circumference according to maximum sum of sensitivity and specificity for detecting hypertension, diabetes, and hypercholesterolemia in men were 89.7 cm, 89.4 cm and 88.2 cm and in women were 93.9 cm, 96.2 cm and 90 cm respectively. The cut-off points of BMI according to maximum sum of sensitivity and specificity for detecting hypertension, diabetes, and hypercholesterolemia in men were 25.7 kg/m(2), 24.8 kg/m(2) and 24 kg/m(2) and in women were 26.9 kg/m(2), 26.3 kg/m(2) and 26.1 kg/m(2) respectively. Conclusions: This was a population-based study on a huge sample on the basis of a national survey. The Iranian BMI was different from the values suggested by the WHO. The waist circumference in Iranian women was higher than that in men.