Relative Skeletal Muscle Mass Is Associated With Hepatic Steatosis in Adolescents With Overweight and Obesity

To assess for myopenia in adolescents with overweight/obesity (OO), and to evaluate relationships between skeletal muscle mass, hepatic steatosis and insulin sensitivity/glycemia.

Secondary analysis of data collected across seven metabolic studies in adolescents with BMI ranging from OO to healthy weight (HW). Appendicular lean mass (ALM) was measured from previously obtained dual energy x-ray absorptiometry (DXA) scans and used to calculate ALM index (ALM (kg)/weight (kg) × 100). Metabolic outcomes included MRI-based fat distribution (hepatic fat fraction [HFF], visceral and subcutaneous fat mass), fasting and glucose-stimulated laboratory assessments of insulin sensitivity, secretion, and glycemia, as obtained in the parent studies. The relationships between ALM index and metabolic outcomes were studied using multivariable linear regression.

ALM was calculated in 304 adolescents-228 with OO (mean age 15.2 ± 2.4 years, Tanner stage 4.5 ± 1.1, 88.2% female) and 76 HW (13.7 ± 2.6 years, Tanner stage 3.4 ± 1.2, 59.2% female). Mean ALM index was significantly lower in OO than HW (23.7% ± 2.9% vs. 31.8% ± 4.5%, p < 0.01). ALM index had a significant association with square-root-transformed HFF (β = -0.09, SE = 0.03, t-value = -2.92, p < 0.01). ALM index was negatively associated with fasting C-peptide (p < 0.01) but not with other markers of insulin sensitivity/glycemia.

Low ALM index had a significant association with hepatic steatosis in adolescents with OO, bringing attention to the interplay between muscle mass and hepatic steatosis in this population. This finding has potential implications for optimal management of metabolic dysfunction-associated steatotic liver disease (MASLD), while the relationship between muscle mass and insulin sensitivity/glycemia requires further attention.

ClinicalTrials.gov identifiers: NCT03717935 (https://clinicaltrials.gov/study/NCT03717935), NCT03041129 (https://clinicaltrials.gov/study/NCT03041129), NCT02157974 (https://clinicaltrials.gov/study/NCT02157974), NCT01775813 (https://clinicaltrials.gov/study/NCT01775813) and NCT03919929 (https://clinicaltrials.gov/study/NCT03919929).