Meta‐analysis: vitamin D and non‐alcoholic fatty liver disease

• Published in: Alimentary pharmacology & therapeutics Vol. 38; no. 3; pp. 246 - 254
• Main Authors: Eliades, M., Spyrou, E., Agrawal, N., Lazo, M., Brancati, F. L., Potter, J. J., Koteish, A. A., Clark, J. M., Guallar, E., Hernaez, R.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 01-08-2013
• Subjects: Biological and medical sciences; Case-Control Studies; Cross-Sectional Studies; Digestive system; Fatty Liver - blood; Fatty Liver - etiology; Gastroenterology. Liver. Pancreas. Abdomen; Humans; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Medical sciences; Non-alcoholic Fatty Liver Disease; Other diseases. Semiology; Pharmacology. Drug treatments; Vitamin D - blood; Vitamin D Deficiency - blood; Vitamin D Deficiency - complications; Digestive diseases; Hepatic disease; Vitamin D; Non alcoholic steatohepatitis; Metaanalysis
• ISSN: 0269-2813; 1365-2036
• DOI: 10.1111/apt.12377

Summary
Background
Non‐alcoholic fatty liver disease (NAFLD) is a highly prevalent condition. Emerging evidence suggests that vitamin D may play a role in the pathogenesis of NAFLD.
Aim
To review systematically the association between vitamin D levels, measured as serum 25‐hydroxy vitamin D [25(OH)D], and NAFLD.
Methods
We used PubMed and EMBASE databases to identify all studies that assessed the association between vitamin D and NAFLD up until 22 April 2013, without language restrictions. We included studies that compared vitamin D levels between NAFLD cases and controls and also those that compared the odds of vitamin D deficiency by NAFLD status. Pooled standardised differences and odds ratios were calculated using an inverse variance method.
Results
Seventeen cross‐sectional and case–control studies have evaluated the association between vitamin D and NAFLD. NAFLD was diagnosed using biopsy (4 studies), ultrasound or CT (10 studies) and liver enzymes (3 studies). Nine studies provided data for a quantitative meta‐analysis. Compared to controls, NAFLD patients had 0.36 ng/mL (95% CI: 0.32, 0.40 ng/mL) lower levels of 25(OH)D and were 1.26 times more likely to be vitamin D deficient (OR 1.26, 95% CI: 1.17, 1.35).
Conclusions
NAFLD patients have decreased serum 25(OH)D concentrations, suggesting that vitamin D may play a role in the development of NAFLD. The directionality of this association cannot be determined from cross‐sectional studies. Demonstration of a causal role of hypovitaminosis D in NAFLD development in future studies could have important therapeutic implications.