Transferrin saturation concentrations associated with telomeric ageing: a population-based study.

There are limited data on the association between Fe overload and leucocyte telomere length (LTL), known as a useful biomarker of the replicative ageing of cells. The aim of the study was to evaluate associations between Fe-status biomarkers and LTL. A cross-sectional study included 1174 men and women aged 50-79 years who provided blood samples for assays of Fe-status biomarkers including ferritin, transferrin saturation (TSAT), total Fe-binding capacity (TIBC) and relative LTL. They were free of hepatitis, potential infection or Fe deficiency. In multiple linear regression analysis adjusted for potential confounding variables, log-transformed LTL was positively associated with TIBC (adjusted coefficient estimate for its highest quartile: 0·17 (se 0·03), P45 %) but also with high-normal concentrations (35-45 %) of TSAT had shorter LTL compared with those with low-normal concentrations (<30 %) (P<0·05). We also observed that less-active or obese persons with high TSAT concentrations had shorter LTL than others. Our findings that cellular ageing is influenced not only by Fe overload but also by high-normal concentrations of TSAT support the hypothesis regarding the detrimental effects of labile Fe, which has a potent pro-oxidant activity in the body.