Longitudinal Links between Changes in Body Composition and Liver Disease Severity in Children and Adolescents with Metabolic Dysfunction-Associated Steatotic Liver Disease.

OBJECTIVE: To investigate the relationship between longitudinal changes in body composition and liver disease severity in children with metabolic dysfunction-associated steatotic liver disease (MASLD). STUDY DESIGN: This longitudinal, single-center, retrospective analysis included patients aged <20 years followed for MASLD who had had ≥2 bioelectrical impedance analyses (BIA) performed. MASLD regression was defined as alanine aminotransferase (ALT) normalization or reduction >50% from baseline. Fat and skeletal muscle mass were adjusted for size by calculating respective indices (dividing by height2). Logistic and linear regressions were used to determine the independent relationship between changes in body composition over time and serologic markers of liver disease severity. RESULTS: 258 patients (75% male, 50% Hispanic) were included with median age of 14 years (IQR: 11, 16) at the time of first BIA. Median body mass index (BMI) z-score at baseline was 2.33 (IQR: 2.04, 2.62). Median time from first to last BIA was 12 months (IQR: 6, 24). A decrease in fat mass index was independently associated with reductions in ALT and gamma glutamyl transferase (GGT) and increased odds of MASLD-regression (OR: 0.55, p<0.001). Fat mass index reduction was superior to BMI z-score in predicting MASLD-regression. Change in skeletal muscle mass index was not associated with change in ALT or GGT. CONCLUSIONS: Changes in fat mass, not skeletal muscle mass, are associated with serologic markers of liver injury in youth with MASLD. Fat mass changes outperform BMI z-score changes in predicting MASLD regression. BIA can serve as an adjunct biomarker of liver disease progression.

Infant versus noninfant formulas and cow's milk: Transition based on age or weight?

Infant formulas are meant to be used until 1 year of age, at which point children are transitioned to non-infant formulas or cow's milk, depending on their remaining dietary intake. Noninfant formulas and cow's milk are appropriate for children who have an average weight at that 1-year mark (9-9.5 kg); however, can contribute significant protein and/or electrolytes to children who are underweight for age, particularly if they still rely heavily on formula feeding for their caloric intake. In this short communication, we present several cases of patients who received excessive amounts of nutrients for age following the formula transition at the 1-year mark. We also provide recommendations for clinicians to consider when faced with underweight infants who are meant to be transitioning off infant formulas.

Body composition measured by bioelectrical impedance analysis is a viable alternative to magnetic resonance imaging in children with nonalcoholic fatty liver disease.

OBJECTIVE: To determine the relationship between bioelectrical impedance analysis (BIA) and magnetic resonance imaging (MRI) obtained measures of body composition in children with nonalcoholic fatty liver disease (NAFLD). METHODS: Youth with obesity and NAFLD who had BIA and abdominal MRI testing were included. BIA measured skeletal muscle mass (SMM), appendicular lean mass (ALM), trunk muscle mass (TMM), and percent body fat. MRI measured total psoas muscle surface area (tPMSA) and fat compartments. Univariate analysis described the relationship between BIA- and MRI-derived measurements. Multivariable regression analyses built a model with body composition measured via MRI. RESULTS: 115 patients (82 (71%) male, 38 (33%) Hispanic, median age14 years) were included. There was a strong correlation between tPMSA and SMM, ALM, and TMM (correlation coefficients [CCs]: 0.701, 0.689, 0.708, respectively; all P < .001). Higher SMM, ALM, and TMM were associated with higher tPMSA. This association remained after controlling for age, sex, ethnicity, type 2 diabetes mellitus status, and body mass index z-score. Total fat mass by BIA and MRI-determined total, subcutaneous, and intraperitoneal fat area correlated significantly (CCs: 0.813, 0.808, 0.515, respectively; all P < .001). In univariate regression, higher total fat mass by BIA was associated with increased total fat area and increased fat in each of the four regions measured by MRI. After controlling for confounders, the association between total fat mass by BIA and total fat area by MRI persisted. CONCLUSIONS: BIA measures of muscle and fat mass correlate strongly with MRI measures of tPMSA and fat areas in children with obesity and NAFLD.

Impedance-based measures of muscle mass can be used to predict severity of hepatic steatosis in pediatric nonalcoholic fatty liver disease.

OBJECTIVES: The objective of this study was to investigate the association between measures of body composition based on bioelectrical impedance analysis (BIA) and histologic severity of liver disease in a pediatric cohort with nonalcoholic fatty liver disease (NAFLD). METHODS: This was a cross-sectional study of patients < 20 y old with histologically confirmed NAFLD followed in our Steatohepatitis Center from 2017 to 2019. Contemporaneous body-composition data were obtained using a multifrequency octopolar BIA device (InBody 370, InBody, Seoul, South Korea). BIA data collected were skeletal muscle mass, appendicular muscle mass, and percentage body fat. Skeletal and appendicular muscle mass were corrected for height (dividing by the square of height), generating their respective indices. Univariate linear and logistic regression, followed by multivariable logistic regression analyses, were used. RESULTS: Of the 79 children included (27% female, 73% male; 38% Hispanic; median age, 13 y; median body mass index Z-score, 2.43), the median NAFLD Activity Score was 4 (interquartile range, 3-5). In multivariable regression analyses, the skeletal muscle mass index was negatively associated with hepatic steatosis after controlling for confounders (odds ratio, 0.76; 95% confidence interval, 0.62-0.93). Similarly, the appendicular muscle mass index was negatively associated with severity of hepatic steatosis severity (odds ratio, 0.69; 95% confidence interval, 0.53-0.90). In contrast, percentage body fat was not associated with hepatic steatosis. NAFLD Activity Score, lobular inflammation, ballooning scores, and fibrosis stage were not associated with measures of body composition. CONCLUSIONS: There is an inverse association between BIA-based measures of muscle mass and severity of hepatic steatosis in children with NAFLD. BIA data could further inform clinical decision making in this context.