Vitamin D and Nonalcoholic Fatty Liver Disease: Bi-directional Mendelian Randomization Analysis.

Abstract

BACKGROUND:

Vitamin D deficiency is associated with nonalcoholic fatty liver disease (NAFLD) in many cross-sectional studies. However, the causality between them has not been established. We used bi-directional mendelian randomization (MR) analysis to explore the causal relationship between 25-hydroxyvitamin D [25(OH)D] and NAFLD.

METHODS:

9182 participants were included from a survey in East China from 2014 to 2016. We calculated weighted genetic risk scores (GRS) for 25(OH)D concentration and NAFLD based on 25(OH)D-related and NAFLD-related single nucleotide polymorphisms. Presence of liver steatosis was assessed using ultrasound. Instrumental variable was used to measure the causal relationship between them.

RESULTS:

An SD increase in the 25(OH)D GRS was significantly associated with 25(OH)D (β 1.29, 95%CI -1.54, -1.04, P<0.05) but not with NAFLD (OR 0.97, 95%CI 0.92, 1.01). An SD increase in NAFLD GRS was also strongly associated with NAFLD (OR 1.09, 95%CI 1.04, 1.15, P<0.05) but not with 25(OH)D (β -0.15, 95%CI -0.41, 0.10). Using an instrumental variable estimator, no associations were found for genetically instrumented 25(OH)D with NAFLD and for genetically instrumented NAFLD with 25(OH)D.

CONCLUSION:

Our results support the conclusion that there is no causal association between vitamin D and NAFLD using a bi-directional MR approach in a Chinese population.

• Authors: Ningjian Wang, Chi Chen, Li Zhao, Yi Chen, Bing Han, Fangzhen Xia, Jing Cheng, Qin Li, Yingli Lu
• Journal: EBioMedicine (EBioMedicine) Vol. 28 Pg. 187-193 (Feb 2018) ISSN: 2352-3964 [Electronic] Netherlands
• PMID: 29339098 (Publication Type: Journal Article)
• Copyright: Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Chemical References

• Vitamin D

Topics

• Genetic Association Studies
• Genetic Pleiotropy
• Genetic Predisposition to Disease
• Humans
• Mendelian Randomization Analysis
• Non-alcoholic Fatty Liver Disease (genetics, metabolism)
• Polymorphism, Single Nucleotide (genetics)
• Risk Factors
• Vitamin D (metabolism)