Telomere length and frailty in older adults—A systematic review and meta-analysis

Telomere shortening has been proposed as a potentially useful biomarker of human ageing and age-related morbidity and mortality. We performed a systematic review and meta-analysis to summarize results from individual studies on the telomere length according to the frailty status and frailty index in older adults. We searched the PubMed, SCOPUS and Web of Science databases to identify studies that evaluated the telomere length in frail and non-frail older adults and the relationship between telomere length and frailty index score. We used the base pairs (bp) as a measure of the telomere length. Summary estimates were calculated using random-effects models. Nine studies were included in the present systematic review and a total of 10,079 older adults were analyzed. We found that the frail older adults (n = 355) had shorter telomeres than the non-frail (n = 1894) (Standardized Mean Difference [SMD] -0.41; 95% CI -0.73 to -0.09; P = 0.01; I² = 82%). Significant differences in telomere length between frail and non-frail older adults were identified in Hispanic (SMD -1.31; 95% CI -1.71 to -0.92; P < 0.0001; I² = 0%) but not in Non-Hispanic countries (SMD -0.13; 95% CI -0.26 to 0.00; P = 0.06; I² = 0%). Similar results were found in the adjusted meta-analysis (SMD -0.56; 95% -1.12 to 0.00; P = 0.05; I² = 85%). A significant but weak relationship was found between telomere length and frailty index analyzing 8244 individuals (SMD -0.06; 95% IC -0.10 to 0.01; P = 0.01; I² = 0%). The current available evidence suggests that telomere length may be not a meaningful biomarker for frailty. Because the potential influence of ethnicity in shortening of telomeres and decline in physiologic reserves associated with aging, additional multiethnic studies are needed.