Effect of Vitamin D Supplementation on Irisin, Telomerase, Klotho, and Tumor Necrosis Factor-alpha (TNF-α) in Elderly: A Quasi-Experimental Study. Althea Med J. 2026;12(4). Accessed August 5, 2026. https://journal.fk.unpad.ac.id/index.php/amj/article/view/4794