Establishing Reference Values for Lean Muscle Mass in the Pediatric Patient

Abstract

Objectives: Adults with decreased muscle mass experience worse outcomes and more frequent complications. The effects of sarcopenia on pediatric outcomes are unknown. Our objective was to define reference values for lean muscle mass in a healthy pediatric population to facilitate future studies on the impact of lean muscle mass on pediatric outcomes. Patients and Methods: Bilateral psoas muscle surface area was measured by computed tomography in a healthy pediatric population undergoing evaluation after trauma. Pearson correlation coefficients (PCCs) were calculated for age, weight, height, body mass index (BMI), total psoas muscle area, and psoas muscle index (PMI; defined as psoas muscle area divided by height squared). Quantile regression was used to determine age- and sex-specific percentiles of psoas muscle area and PMI. Results: Analysis of 494 male and 288 female patients with available imaging (median age: 9.3 years, interquartile range: 5.4–13.4; 63.1% male) was performed. For males, age correlated strongly with total psoas volume (PCC = 0.87), height (0.95), and weight (0.88) and poorly with BMI (0.45). In females, age correlated strongly with total psoas volume (0.88), height (0.92), weight (0.88) and poorly with BMI (0.19). Gender-specific curves and charts were created using output from the quantile regression from reference values of the total psoas muscle area corresponding to the 25th, 50th, and 75th percentiles across all ages. Conclusions: We created gender-specific reference charts for total and height-normalized psoas muscle area in healthy children based on age. These results can be used in future studies to establish the effects of sarcopenia in pediatric patients.

The impact of sarcopenia and sarcopenic obesity on survival in children with Ewing sarcoma and osteosarcoma

“…It is, for example, known that body weight is proportional to height cubed and not height squared during puberty [ 16 ]. In the work by Metzger et al [ 10 ], the psoas muscle index was not a linear function but was lower around the age of 8 years than in other age groups and was more pronounced in boys.…”

“…Most reported reference values for muscle area only take age and sex into consideration, without any normalization using patient height or weight. On the other hand, a study by Metzger et al [ 10 ] and a more recent study by Somasundaram et al [ 11 ] also reported muscle indices for total psoas muscle area and total abdominal muscle area, respectively. The study by Somasundaram is especially valuable because it was performed in 2,168 patients.…”

Impact of muscle mass on the prognosis of liver transplantation for infants with biliary atresia

“…Previous published studies were based on a control group in this population ( 13 , 26 ), and recently Lurz et al published curves of tPMA for a Canadian population of 779 children, but did not include children under 1 year of age ( 25 ). Metzger et al published curves of tPMA in a group of 782 patients in the US and also included a small set of children under 1 year of age, but showing only p25-p50 values and no clear cut-off points ( 27 ). As we do not currently have enough abdominal CT images of healthy children under one year of age to include a control group for our population, we decided to study psoas muscle mass as a continuous variable in our statistical analyses.…”

“…The first handicap in our study was trying to establish a cutoff point to define sarcopenia in children under 1 year of age. Previous published studies were based on a control group in this population (13,26) (27). As we do not currently have enough abdominal CT images of healthy children under one year of age to include a control group for our population, we decided to study psoas muscle mass as a continuous variable in our statistical analyses.…”

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“…On the contrary, there is emerging evidence for the use of the tPMA to determine pediatric sarcopenia as a risk factor for poor outcome in solid organ transplantation, hematologic disorders, or acute appendicitis (3,19,21,57,60). Three complementary pediatric reference values for the tPMA are currently available (10,61,62).…”