The usefulness of bioelectrical body composition analysis (BIA) in the proper assessment of nutritional status in children and adolescents with idiopathic scoliosis (IS)

Abstract

Methods For a total of 317 IS patients (240 girls and 77 boys), mean age 14.11±2.79y, the scoliotic curve was assessed by Cobbs angle and angle vertebra rotation (AVR). Height, weight, waist and hip circumferences were measured and BMI, BMI Z-score, waist/height ratio (WHtR) and waist/ hip ratio (WHR) were calculated for the entire group. Body composition parameters, such as fat mass (FAT), fat-free mass (FMM), predicted muscle mass (PMM) and total body water (TBW), were evaluated using a bioelectrical impedance analyzer. Nutritional status was classified by centile charts for BMI as underweight, normal weight, overweight or obese, and for FAT% as underfat, lean, overfat or adiposity. This was a prospective, randomized study. Results Nutritional status assessed by BMI has been associated with 21.1% of misclassification compared to BIA. There were important differences between the percentage of underweight vs. underfat patients (13.9% vs. 9.5%), overweight vs. overfat (5.4% vs. 7.9%) and obesity vs. adiposity (2.8% vs. 5.0%). There was no significant correlation between BMI and scoliosis severity in the subgroups classified by standard measurement. However, the BMI Z-score correlated significantly with Cobb and AVR in every BMI-classified subgroup. There were also significant correlations between body composition parameters (BIA) and vertebral deformity in only the normal BMI group. After the correction to the FAT%, 252 (78.9%) children were properly classified; of this group of IS patients, statistical analysis showed strong (p<0.001), significant correlation between either Cobb’s angle or AVR vs. every (standard and bioelectrical) anthropometrical parameter.