Trunk Fat Estimation According To Gender In Childhood Through Basic Somatic Readings. An Opportunity for Improving Girl’S Evaluation

Abstract Background: Easy appraisal of trunk fat and the eventual cardiometabolic risk of pediatric obesity is a present requirement. Its estimators Waist-to-Height Ratio (WHtR) and Relative Fat Mass pediatric (RFMp, expressed as % of total fat content), can be a complement of widely accepted BMI.Methods: 472 children (39% boys), classified as underweight, normal weight, overweight and obese (Nutritional groups, NG) according to BMI Z-score after their strictly obtained anthropometric initial data, with ad hoc exclusion criteria. Calculation of WHtR and RFMp was done for each nutritional group and sex, as associations through multiple linear regression (MLR) and differences among sexes (medians, IQR).Results: Age (mean (95% CI)), 10.8 y (10.1- 11.1). Estimators values in: All group WHtR 0.5 (0.49 – 0.51), RFMp% 32.3 (31.7 – 33.0); Underweight, WHtR 0.41 (0.40 – 0.41), RFMp (%) 22.8 (21.2 – 24.4); Normal weight, WHtR 0.46 (0.45 – 0.47), RFMp(%) 28.9 (28.1 – 29.7); Overweight, WHtR 0.51 (0.50 – 0.52), RFMp(%) 34.2 (33.3 – 35.1) and Obese WHtR 0.56 (0.55 – 0.57), RFMp(%) 37.8 (36.9 – 38.6). Associations (NG; independent variables): In NG adjusted R² values were between 0.74-0.78. In All group Beta coefficients were for RFMp 3.36 (P< 0.001) for girls; for waist circumference (WC 2.97 (P< 0.001) and for WHtR were respectively -0.01 (p< 0.001) and 0.03 (p< 0.001) Sex differences: BMI were in NG without gender differences (Mann-W’s U). Whereas WHtR (median IQR) differ (M vs F) respectively in: All group 0.49 (0.45 - 0.54) vs 0.52 (0.45 - 0.56), p<0.004; in Overweight 0.51 (0.48 – 0.53) vs 0.54 (0.51 – 0.55), p< 0.001; in Obese 0.55 (0.52 – 0.57) vs 0.57 (0.54 – 0.60), p< 0.004. RFMp (%): in All 29.21 (24.27 – 32.92) vs 36.63 (30.2 – 39.51), p< 0.001; in Overweight 31.24 (28.35 – 32.35) vs 37.95 (35.75 – 38.82), p<0.001 and in Obese 35.89 (32.05 – 36.15) vs 40.63 (38.27 – 42.42), p<0.001.Conclusions: WHtR and RFMp are simple and reliable indexes not requiring centile charts. Their values, including waist circumference, can estimate the different trunk fat component in boys and girls better than BMI, especially if overweight and obese. RFMp proved to be more reliable as it considers gender. Reasonably, both should be included in routine anthropometric readings.