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 APOE 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 APOE 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 APOE genotype were determined by real-time PCR. A significant association was observed between shorter TL and an increased risk of CI (p < 0.001). Although APOE 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 (p < 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 (p < 0.0001). Overall, individuals with both shorter telomeres and lower educational levels exhibited the highest risk of CI. APOE ε4 may contribute to telomere shortening.