U-Shaped Relationship of Leukocyte Telomere Length With All-Cause and Cancer-Related Mortality in Older Men.

Abstract

Telomeres are essential DNA-protein complexes whose attrition results in cellular dysfunction and senescence. Leukocyte telomere length (LTL) correlates with tissue telomere length, representing a biomarker for biological age. However, its predictive value for mortality risk, and for cardiovascular versus cancer deaths, in older adults remains uncertain. We studied 3608 community-dwelling men aged 77.0 ± 3.6 years. Leukocyte telomere length was measured using multiplex quantitative PCR, expressed as amount of telomeric DNA relative to single-copy control gene (T/S ratio). Deaths from any cause, cardiovascular disease (CVD), and cancer were ascertained using data linkage. Curve fitting used restricted cubic splines and Cox regression analyses adjusted for age, cardiometabolic risk factors, and prevalent disease. There was a U-shaped association of LTL with all-cause mortality. Men with T/S ratio in the middle quartiles had lower mortality (quartiles, Q2 vs Q1, hazard ratio [HR] = 0.86, 95% confidence interval [CI] 0.77-0.97, p = .012; Q3 vs Q1 HR = 0.88, CI 0.79-0.99, p = .032). There was no association of LTL with CVD mortality. There was a U-shaped association of LTL with cancer mortality. Men with LTL in the middle quartiles had lower risk of cancer death (Q2 vs Q1, HR = 0.73, CI 0.59-0.90, p = .004; Q3 vs Q1, HR = 0.75, CI 0.61-0.92, p = .007). In older men, both shorter and longer LTL are associated with all-cause mortality. A similar U-shaped association was seen with cancer deaths, with no association found for cardiovascular deaths. Further research is warranted to explore the prognostic utility of LTL in ageing.