Shorter Telomeres Precede Dementia

Telomere length has been proposed as a marker of biological aging. Shorter telomeres have been linked with higher mortality within a given period of time and an increased risk of some chronic diseases.

Researchers at the Twin Research & Genetic Epidemiology Unit, Kings College London, School of Medicine, UK evaluated the relationship between cognitive function and leukocyte telomere length. They evaluated episodic memory and associated learning, recognition memory for non-verbal patterns, and working memory capacity in 382 women with a mean age of 50.6 years.

After adjusting for age and estimated prior intellectual ability, researchers observed significant correlations of leukocyte telomere length (LTL) with episodic memory and associated learning (p=0.032), recognition memory for non-verbal patterns (p=0.007), and working memory capacity (p=0.003).

In pairs of twins with differing telomere length, researchers found that the sister with longer telomeres had significantly better recognition memory and working memory capacity than her sister.

The researchers concluded that leukocyte telomere length correlates with measures of cognitive performance, suggesting that LTL might be a biomarker of cognitive aging before onset of dementia.

Abstract

BACKGROUND: Age-related cognitive decline begins in mid-life and continues with advancing age. Leukocyte telomere length (LTL) shortens with age, and inflammation and oxidative stress enhance this process. Shorter LTL is associated with dementia. METHODS: The relationship between cognitive function and LTL was investigated in a cross-sectional study of 382 women (mean age 50.6 years, range 19-78), not diagnosed with any form of dementia or cognitive impairment, from the TwinsUK cohort using six tests from the Cambridge neuropsychological test automated battery (CANTAB). RESULTS: After adjusting for age and estimated prior intellectual ability, we observed significant correlations of LTL with episodic memory and associated learning (PAL, p=0.032), recognition memory for non-verbal patterns (DMS, p=0.007), and working memory capacity (SSP, p=0.003). In pairs of twins discordant for LTL the twin with longer telomeres also had significantly better DMS (p<0.05) and SSP (p<0.013) scores than their co-twin with shorter telomeres. The correlations between these two scores and LTL was significant both in women over the median mean age and in those below the median age, and remained significant after statistical adjustment for potential confounders. CONCLUSIONS: Leukocyte telomere length correlates with a subset of measures of cognitive performance, suggesting that it might be a biomarker of cognitive aging in women before the onset of dementia.

Source

Valdes AM, Deary IJ, Gardner J, Kimura M, Lu X, Spector TD, Aviv A, Cherkas LF. Leukocyte telomere length is associated with cognitive performance in healthy women. Neurobiol Aging. 2008 Aug 19. [Epub ahead of print] PMID: 18718693 [PubMed - as supplied by publisher]

Key concepts: telomere length, dementia risk