Waist Circumference Can Exclude Insulin Resistance and Identify Those At Greates

A waist circumference of less than 39.4in.(100 cm) excludes individuals of both sexes from being at risk of being insulin resistant.

Although insulin resistance is an important pathogenic factor in common metabolic disorders, no easy clinical test exists for predicting the insulin resistance of an individual. Swedish researchers assessed how effectively different anthropometric measurements and biochemical markers used in clinical practice can predict insulin sensitivity by analyzing a sample of 2 746 healthy volunteers (798 male) from retrospectively collected data. Ages ranged from 18 years to 72 years, BMI from 18 to 60, and waist circumferences from 65 cm to 150 cm. They determined height, weight, waist circumference (mid-way between the lateral lower ribs and the iliac crest), and hip circumference. Results from analyses of venous plasma for glucose, insulin, lipids, and leptin concentrations were used.

They found: "In the multiple regression model, waist circumference was the strongest regressor of the five significant covariates (standardized partial regression coefficients: waist circumference 1 = 0.37; log-plasma triglycerides 2 = 0.23; systolic blood pressure 3 = 0.10, high density lipoprotein cholesterol 4 = -0.09; and body mass index 5 = 0.15 (P < 0.001)).

The researchers concluded: “A waist circumference of < 39.37in (100 cm) excludes individuals of both sexes from being at risk of being insulin resistant. Waist circumference is a strong independent risk factor for insulin resistance and the most powerful regressor in our model. It replaces body mass index, waist:hip ratio, and other measures of total body fat as a predictor of insulin resistance and explains more than 50% of the variation in insulin sensitivity alone. Current guidelines suggest a cut-off of 40.16in (102 cm) in men and 34.6in.(88 cm) in women, on the basis of the many metabolic risk factors after waist circumference is stratified in fifths. However, with 34.65 in (88 cm) as a cut-off in women the specificity drops markedly. In the San Antonio heart study, twice as many women as men had a waist circumference above the level given in the current guidelines, whereas the prevalence of the metabolic syndrome was similar in both sexes, thus supporting the notion that abdominal obesity is overestimated in women. The coupling of insulin resistance with abdominal obesity suggests a biological link at the fat cell level. Hyperinsulinaemia activates 11-hydroxysteroid dehydrogenase in omental adipose tissue, thus generating active cortisol and promoting a cushingoid fat distribution.

Waist circumference is a simple tool to exclude insulin resistance and to identify those at greatest risk (therefore those who would benefit most from lifestyle adjustments).”

BMJ 2005;330:1363-1364. 11 June 2005 Use of waist circumference to predict insulin resistance: retrospective study, Hans Wahrenberg, Katarina Hertel, Britt-Marie Leijonhufvud, Lars-Göran Persson, Eva Toft and Peter Arner.