ABSTRACT
Despite current literature pointing to a link between shortened telomeres and aging, chronic diseases, and geriatric syndromes, the precise implications of this connection remain unclear. The aim of this exploratory, cross-sectional, observational study was to investigate the association between the relative telomere length (RTL) of peripheral blood leukocyte subtypes (mononuclear cells and granulocytes) and physical performance using the Short Physical Performance Battery (SPPB) in older adults. A cohort of 95 participants was recruited, which included men and women aged over 60 years (70.48 ± 5.5 years). It was found that mononuclear cell RTL was significantly lower than that of granulocytes (p < 0.0001). Moreover, individuals with good SPPB performance exhibited lower mononuclear cell RTL compared with those with moderate or poor performance. However, no significant differences were observed in granulocyte RTL between different SPPB performance groups. The global SPPB score showed an inverse correlation with mononuclear cell RTL, but this correlation was not present with granulocyte RTL. Similarly, the SPPB sit-to-stand domain correlated with mononuclear cell RTL, but no such correlation was found with granulocyte RTL. Our findings challenge conventional expectations, suggesting that shorter mononuclear cell RTL may be associated with favorable functional capacity. The variations in RTL between mononuclear cells and granulocytes highlight their distinct biological roles and turnover rates. A history of immune responses may influence mononuclear cell RTL dynamics, while telomerase activity may protect granulocyte RTL from significant shortening. The unexpected associations observed in mononuclear cell RTL emphasize the complex interplay between immune responses, cellular aging, and functional capacity in older adults.