Accelerometry-assessed sleep and liver health in adolescents and adults: Links to liver enzymes, MASLD, and MRI-derived liver fat.

BACKGROUND

To investigate associations of accelerometry-assessed sleep characteristics with liver enzymes and liver fat in adolescents and adults.

METHODS

We analyzed data from four German cohorts: GINIplus and LISA (n = 1132, 14-16 years), KORA-Fit (n = 1318, 53-74 years), and KORA-MRI (n = 108, 48-67 years). Eleven accelerometry-assessed sleep characteristics captured sleep quantity, efficiency, fragmentation, latency, and timing. Liver enzymes included alanine aminotransferase (ALT), aspartate aminotransferase, and gamma-glutamyl transferase (GGT). Adult liver fat markers were steatotic liver disease (SLD) and metabolic dysfunction-associated SLD (MASLD, plus ≥1 cardiometabolic risk factor and without excessive alcohol intake), defined by fatty liver index (FLI, ≥60) or 3T-Magnetic Resonance Imaging (MRI) derived proton density fat fraction (PDFF, ≥5 %). Linear and logistic regression models were evaluated.

RESULTS

Time awake per hour after sleep onset (WASO/h) was associated with higher ALT both in adolescents (percentage change [95 % confidence interval, CI] per interquartile range [IQR]: 3.82 [0.86, 6.87]) and adults (3.05 [0.38, 5.78]). In adults, WASO/h was associated with increased odds of SLD-FLI (odds ratio [95 %CI] per IQR: 1.47 [1.26, 1.71]), MASLD-FLI (1.61 [1.34, 1.94]), SLD-PDFF (2.10 [1.16, 3.78]), and MASLD-PDFF (3.32 [1.47, 7.52]). Similar results were observed for poor sleep efficiency and sleep fragmentation index. However, these associations lost significance after body mass index (BMI) adjustment. Significant interactions between WASO/h and BMI groups were observed for ALT, GGT, and SLD-FLI.

CONCLUSIONS

Objectively measured sleep fragmentation was associated with increased liver enzymes in adolescents and hepatic steatosis in adults, with BMI potentially mediating or modifying these associations.