The association of serum levels of vitamin D with leucocyte telomere length, as a marker of biological aging: A meta-analysis.

Abstract

<h4>Background</h4>Short telomere length (TL) has been associated with chronic diseases and reduced lifespan. Vitamin D may help preserve telomeres through its anti-inflammatory effects; however, the relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and TL remains inconclusive. This meta-analysis was conducted to evaluate the association between circulating 25(OH)D and leukocyte TL (LTL).<h4>Methods</h4>A comprehensive literature search was performed across PubMed, Scopus, Google Scholar, ClinicalTrials.gov, and Cochrane Library to identify relevant studies published up to February 2025. Standardized β coefficients with 95% confidence intervals were applied as the effect size metric to evaluate the associations using a random effect model.<h4>Results</h4>A total of 21 studies comprising 185,191 participants were analyzed. The overall results demonstrated a positive association between serum 25(OH)D levels and LTL (β = 0.04, 95% CI = 0.02-0.06), with remarkable heterogeneity across studies (I²= 89.1%, P ≤.001). This association was supported in adults (β = 0.04, 95% CI = 0.03-0.06), women (β = 0.05, 95% CI = 0.01-0.08), individuals with vitamin D deficiency (β = 0.22, 95% CI = 0.01-0.43), and studies that adjusted for covariates (β = 0.05, 95% CI = 0.01-0.08). No significant associations were found in men, participants with serum 25(OH)D levels ≥ 30 ng/mL, children, or studies without covariate adjustments. The relationships were not influenced by the method of TL assessment, body mass index, smoking status, and sample size.<h4>Conclusion</h4>Serum 25(OH)D levels showed a positive correlation with LTL in women, adults, and individuals with vitamin D deficiency.