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Lidia Ostrowska-Nawarycz, Tadeusz Nawarycz
Med Sci Tech 2010; 51(1): 21-27
Introduction: Early diagnosis of abdominal obesity in children based on current appropriate norms appears to be of great importance. Recently, the Waist-to-Height Ratio (WHtR) is more and more recommended as a simple age and gender independent index of visceral fat. We analyzed the WHtR in children and youth considering the following aspects: 1/ its sexual dimorphism, 2/ cut-off values.
Patients and methods: A total of 26,525 children and youth aged 7-19 years from the city of Łódź (Poland) were examined. In all subjects the basic anthropometric parameters (body mass and height, waist circumference (WC)) were measured and the BMI and WHtR indices were calculated. Using the LMS method, the percentile distribution of the WHtR was evaluated. The sexual dimorphism indices for WHtR, WC and BMI were evaluated using the sexual dimorphism indices (SDI) defined as: SDI = 2(Xg-Xb)/(SDb+SDg), where Xg, Xb, SDg, SDb – mean values of the analyzed X index and Standard Deviation SD for girls and boys, respectively.
Results: The mean value of WHtR corresponding to the 90th percentile was significantly (p<0001) higher for boys (boys: WHtR = 0.497; 95%CI: 0.491 – 0.502; girls: WHtR = 0.479; 95%CI: 0.475 – 0.485). Both WHtR percentile curves and SDI values for WHtR (SDIWHtR) show boys predominance in all the analyzed period. The SDI values for WHtR (SDIWHtR ) in comparison to WC are more stable, particularly in the youth group (>13 years).
Conclusions: 1/ The WHtR for the examined group is characterized by significant sexual dimorphism (with boys’ predominance, particularly for 12 years old) and age influence; 2/ In evaluation of abdominal obesity in children, the WC is simpler for practical use compared to WHtR; 3/ Further studies are needed to work out one acceptable WC measurement protocol for both adults and schoolchildren.
Keywords: abdominal obesity, children, youth, Waist-to-Height Ratio, sex dimorphism