Shrinking Telomeres May Foretell Dementia

Telomeres are the end caps of chromosomes, protecting the DNA complexes from deterioration during cell division. Telomere shortening is considered a marker of cellular aging, and prematurely shortened telomeres have been linked to increased risk of cancers, heart disease, dementia and death.  Lawrence Honig, from Columbia University (New York, USA), and colleagues assessed DNA samples from participants enrolled in the Washington Heights-Inwood Community Aging Project.  The team used real-time polymerase chain reaction (PCR) to determine mean telomere length in 1,983 patients who had a mean age of 78 and who were followed for mortality for a mean of 9.3 years. During the study, 190 patients (9.6%) developed incident dementia.  Confirming findings of previous studies, the researchers found that telomere length was inversely related to age and was shorter in men than in women.  Further, they found that patients who died during follow-up had shorter mean telomere length than survivors, and the association remained even after adjusting for age, sex, education, and apolipoprotein E genotype status.  The team also determined that patients who developed dementia had significantly shorter telomere length (6,131 base pairs for prevalent cases and 6,315 base pairs for incident cases, as compared with 6,431 base pairs for those remaining dementia-free.)   The study authors conclude that: “Our findings suggest that shortened leukocyte [telomere length] is associated with risks for dementia and mortality and may therefore be a marker of biological aging.”