High Discrepancy in Abdominal Obesity Prevalence According to Different Waist Circumference Cut-Offs and Measurement Methods in Children: Need for Age-Risk-Weighted Standardized Cut-Offs?

BACKGROUND: Waist circumference (WC) is a good proxy measure of central adiposity. Due to the multiplicity of existing WC cut-offs and different measurement methods, the decision to use one rather than another WC chart may lead to different prevalence estimates of abdominal obesity in the same population. Aim of our study was to assess how much the prevalence of abdominal obesity varies in Italian schoolchildren using the different available WC cut-offs. METHODS: We measured WC at just above the uppermost lateral border of the right ilium in 1062 Italian schoolchildren aged 7-14 years, 499 living in Northern Italy and 563 in Southern Italy. Abdominal obesity was defined as WC ≥90th percentile for gender and age according to nine WC charts. RESULTS: We found an extremely high variability in the prevalence of abdominal obesity detected in our study-populations according to the different WC charts, ranging in the overall group from 9.1% to 61.4%. In Northern Italy children it varied from 2.4% to 35.7%, and in Southern ones from 15.1% to 84.2%. CONCLUSIONS: On the basis of the chosen WC cut-offs the prevalence of abdominal obesity varies widely, because percentile-charts are strongly influenced by the population status in a particular moment. A further rate of variability may lay on the site of WC measurement and on the statistical method used to calculate WC cut-offs. Risk-weighted WC cut-offs measured in a standardized anatomic site and calculated by the appropriate method are needed to simply identify by WC measurement those children at high risk of cardio-metabolic complications to whom specific and prompt health interventions should be addressed.