TL change is rated consistently in continuous and categorical decrements.
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Short TL corresponds to high hazard of all-cause mortality in general population.
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TL is not a good biomarker of ageing among the oldest old of over 80 years.
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Precision of TL measurement methods matters for the hazard estimation.
Abstract
Telomere attrition is associated with increased morbidity and mortality of various age-related diseases. Reports of association between telomere length (TL) and all-cause mortality remain inconsistent. In the present study, a meta-analysis was performed using published cohort studies and un-published data from the Swedish Twin Registry (STR). Twenty-five studies were included: four STR cohorts (12,083 individuals with 2517 deaths) and 21 published studies. In the STR studies, one standard deviation (SD) decrement of leukocyte TL corresponded to 13% increased all-cause mortality risk (95% confidence interval [CI]: 7%–19%); individuals in the shortest TL quarter had 44% higher hazard (95% CI: 27%–63%) than those in the longest quarter. Meta-analysis of all eligible studies (121,749 individuals with 21,763 deaths) revealed one SD TL decrement-associated hazard ratio of 1.09 (95% CI: 1.06–1.13); those in the shortest TL quarter had 26% higher hazard (95% CI: 15%–38%) compared to the longest quarter, although between-study heterogeneity was observed. Analyses stratified by age indicated that the hazard ratio was smaller in individuals over 80 years old. In summary, short telomeres are associated with increased all-cause mortality risk in the general population. However, TL measurement techniques and age at measurement contribute to the heterogeneity of effect estimation.
Graphical abstract
Hazard of all-cause mortality with respect to one standard deviation TL decrement (in the left) and comparing the shortest to the longest TL quarter (in the right) in the meta-analyses of the STR and published studies. TL, telomere length; STR, the Swedish Twin Registry.
