AUTHOR=Lu Zhe , Jiao Yang , Li Jun 

TITLE=Higher Genetically Predicted Triglycerides, LDL, and HDL Increase the Vitamin D Deficiency: A Mendelian Randomization Study

JOURNAL=Frontiers in Nutrition

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.862942

DOI=10.3389/fnut.2022.862942

ISSN=2296-861X

ABSTRACT=Introduction: It has been proven that high body mass index (BMI) levels can cause vitamin D deficiency, but the mechanism is still unclear. Therefore, this study attempts to explain this phenomenon from the perspective of blood lipid by using mendelian randomization (MR). 
Methods: Genome-wide association studies (GWAS) summary datasets for serum lipids were obtained from Global Lipids Genetics Consortium (GLGC). Vitamin D deficiency outcome data were acquired from the UK Biobank samples. Single-variable MR (SVMR) and multi-variable MR (MVMR) analyses were conducted using the TwoSampleMR package based on R 4.0.3. The random-effect inverse-variance weighted (IVW), MR-Egger, weighted-median method, and weighted mode were the four main methods. 
Results: In the SVMR of serum lipid/apolipoprotein levels on serum vitamin D level, it was found that elevated serum triacylglycerol (IVW, OR=0.85, 95%CI: 0.81-0.89, P<0.001), low-density lipoprotein (LDL) (IVW, OR=0.93, 95%CI: 0.90-0.95, P<0.001) and high-density lipoprotein (HDL) (IVW, OR=0.95, 95%CI: 0.91-0.98, P<0.001) levels were all have a causal relationship with vitamin D deficiency, but significant pleiotropy was detected in the triacylglycerol (P=0.001) and HDL (P=0.003) analysis. MVMR analysis results were consistent with SVMR. 
Conclusion: By using single-variable mendelian randomization and multi-variable mendelian randomization methods, we identified that the elevated serum triacylglycerol, LDL, and HDL levels all had a causal relationship with vitamin D deficiency. Taking into account the significant pleiotropy demonstrated in this study, the conclusions of this study should be treated with caution.