Combined Impact of Telomere Length and Mitochondrial DNA Copy Number on Cognitive Function in Community-Dwelling Very Old Adults

Abstract

Background: This study was conducted to investigate the combined impact of telomere length and mitochondrial DNA (mtDNA) copy number on cognitive function in community-dwelling very old adults. Methods: In total, 186 subjects over 75 years participated in this study. Cognitive function was assessed using the Korean Mini-Mental State Examination, and leukocyte telomere length and mtDNA copy number were measured using real-time polymerase chain reaction methods. Results: Both the fourth quartile of telomere length and mtDNA copy number were associated with cognitive dysfunction with an adjusted odds ratio of 0.23 (95% confidence interval (CI), 0.10-0.75) and 0.18 (95% CI, 0.03-0.54), respectively. Participants in the high telomere length/high mtDNA copy number group were more likely to have cognitive dysfunction than participants in the low telomere/low mtDNA copy number group with an adjusted odds ratio of 0.19 (95% CI, 0.07-0.58). Conclusion: Our results collectively suggest that the combination of telomere length and mtDNA copy number may be useful for monitoring cognitive decline in older adults.