Shorter Telomere Length in Individuals with Neurocognitive Disorder and APOE ε4 Genotype

Neurocognitive disorders (NCD) are neurodegenerative diseases characterized by decline or loss of cognitive functions. Aging and the <i>APOE</i> genotype have been identified as major risk factors. Telomere length (TL) has been proposed as a biomarker of aging, with shorter TL associated with cognitive decline. This study investigated the relationship between TL and the <i>APOE</i> genotype in individuals with cognitive impairments (CIs). A total of 170 participants aged >55 years were included. Cognitive function was assessed using the MMSE and MoCA tests. Relative telomere quantification and <i>APOE</i> genotype were determined by real-time PCR. A significant association was observed between shorter TL and an increased risk of CI (<i>p</i> < 0.001). Although <i>APOE</i> ε4 is a known genetic risk factor, its association with CI was less clear in this study population, as a considerable proportion of ε4 carriers did not present cognitive impairment (<i>p</i> < 0.05). However, ε4 carriers with CI tended to have shorter TL than those with non-cognitive impairment (NCI-SMC). Furthermore, fewer years of education were strongly correlated with higher CI risk (<i>p</i> < 0.0001). Overall, individuals with both shorter telomeres and lower educational levels exhibited the highest risk of CI. <i>APOE</i> ε4 may contribute to telomere shortening.