Assessment of serum vitamin D level in relation to liver functions and fibrosis in cholestatic infants with biliary atresia

Abstract Background Biliary atresia (BA) is the most urgent cause of neonatal cholestasis and is frequently complicated by fat-soluble vitamin deficiency. This study aimed to investigate serum vitamin D status in cholestatic infants with BA and its relationship to liver function and histologic fibrosis. Methods This analytical cross-sectional study enrolled 50 infants with BA (30–100 days) and 25 age- and sex-matched healthy controls. BA was suggested by El-Guindi score ≥ 23.9 and confirmed by intraoperative cholangiography. Serum 25-hydroxyvitamin D was measured and categorized as deficiency (< 20 ng/mL), insufficiency (20–<30 ng/mL), or sufficiency (≥ 30 ng/mL). Liver function tests, coagulation profile, abdominal ultrasonography, and liver biopsy fibrosis staging were assessed in BA cases. Results BA infants had markedly lower vitamin D than controls (median 15 [IQR 13.75–21] vs. 33 [32–34] ng/mL, P = 0.001). Vitamin D deficiency and insufficiency occurred in 60% (30/50) and 40% (20/50) of BA infants, respectively, while all controls were sufficient ( P = 0.001). Compared with insufficiency, deficiency was associated with older age (78.87 ± 13.14 vs. 42.45 ± 4.79 days, P = 0.001), splenomegaly (40% vs. 0%, P = 0.001), larger liver span (8.3 ± 0.75 vs. 6.53 ± 0.55 cm, P = 0.001), higher total bilirubin (10.81 ± 1.44 vs. 9.55 ± 1.57 mg/dL, P = 0.005) and ALP (832.07 ± 39.58 vs. 686.3 ± 42.15 IU/L, P = 0.001), and worse coagulation (INR 1.2 [1.08–1.3] vs. 1.0 [0.9–1.0], P = 0.001). Vitamin D declined stepwise with fibrosis severity (mild 21 [21–22], moderate 14 [14–15], marked 10 [9–10] ng/mL; P = 0.001). Conclusions Vitamin D deficiency/insufficiency was universal in BA and was linked to worse cholestasis, impaired synthetic function, and advanced fibrosis, supporting routine assessment and early targeted correction in BA care. Also, vitamin D may be a marker rather than mediator of advanced disease.