Computed tomography-based muscle and fat composition in a Dutch population: a cross-sectional study.

BACKGROUND: Normative adult body composition values from North American patients were recently provided, yet sex- and age-specific reference values for Europeans remain unexplored. MATERIALS AND METHODS: This cross-sectional study was performed on adult trauma patients who underwent CT imaging that included the abdomen in the University Medical Center Utrecht, a level-1 trauma center, between January 2017 and December 2020. An artificial intelligence algorithm was used to automatically segment muscle and fat components on axial CT images at the level of the third lumbar vertebra. Measurements included areas and attenuation values for muscle and fat, including total muscle areas and "pure-muscle" sub-areas. Skeletal muscle indices were calculated by dividing skeletal muscle areas by the squared height of patients. Age- and sex-specific percentile curves for all parameters were generated. RESULTS: Of the 2383 adult trauma patients who underwent CT imaging that included the abdomen, 2286 were included. The median age was 53 years (IQR 32-69), and 67.2% were male. The mean BMI was 25.4 ± 4.4 kg/m2. The total muscle index decreased with age starting around 60 years in males. In females, the total muscle index decreased with age when intramuscular fat was excluded from the analysis. Mean muscle attenuation of all included muscles showed substantial declines with age in both sexes. Visceral fat areas increased rapidly with age in both sexes, yet with higher values among males. CONCLUSION: This study provides CT-derived populational body composition parameters established in Dutch adults, intended to be used as reference values in clinical practice. CRITICAL RELEVANCE STATEMENT: Obesity and sarcopenia are risk factors for various diseases and mortality. CT-based body composition assessment provides precise muscle and fat data, enabling personalized treatment plans and early identification of individual risks, ultimately improving patient outcomes and care management strategies. KEY POINTS: European reference values of CT-derived muscle and fat parameters are not yet well established. This study provides Dutch reference curves and values of CT-derived body composition. CT-derived body composition assessment enables personalized risk assessment and treatment.