Serum complement C3 as a diagnostic biomarker for metabolic dysfunction -associated steatotic liver disease in middle-aged and elderly adults: a cross-sectional study

Serum C3 is a promising diagnostic biomarker for MASLD in middle-aged and elderly adults, showing a distinct nonlinear relationship and strong discriminative ability. However, complement levels were not independently associated with liver fibrosis in this population. These findings suggest a potential role for C3 in MASLD diagnosis, but the cross-sectional design precludes causal inference, and further longitudinal studies are needed to confirm its clinical utility and elucidate underlying mechanisms.