Impact of serum 25-hydroxyvitamin D 25(OH) on telomere attrition: A Mendelian Randomization study

Background: Conventional observational studies have suggested that 25-hydroxyvitamin D (25(OH)D) is inversely associated with telomere shortening. We aimed to apply two-sample Mendelian randomization (MR) to assess the causal association between serum 25(OH) D and telomere length (TL). Methods: MR was implemented by using summary-level data from the largest genome-wide association studies (GWAS) on vitamin D (n = 73 699) and TL (n = 37 684). Inverse variance weighted method (IVW) was used to estimate the causal estimates. Weighted median (WM)-based method, and MR-Egger, leave one-out were applied as sensitivity analysis. Results: The results of MR demonstrated no effect of 25(OH)D on TL (IVW = beta:-0.104, p = 0.219, WM = beta:-0.109, p = 0.188; MR Egger = beta:-0.127, p = 0.506). None of the 25(OH)D-related single nucleotide polymorphisms (SNPs) were significantly associated with TL. Heterogeneity tests did not detect heterogeneity. Furthermore, MR pleiotropy residual sum and outlier (MR-PRESSO) did not highlight any outliers (p = 0.424). Results of leave-one-out method demonstrated that the links are not driven because of the single SNPs. Conclusions: Our study does not support any causal effect of 25(OH) D on TL. (c) 2019 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.