title: Association of shorter leukocyte telomere repeat length with dementia and mortality.
abstract: BACKGROUND
  Shortening of chromosomal telomeres is a consequence of cell division and is a biological factor related to cellular aging and potentially to more rapid organismal biological aging.
  
  
  OBJECTIVE
  To determine whether shorter telomere length (TL), as measured in human blood samples, is associated with the development of Alzheimer disease and mortality.
  
  
  METHODS
  We studied available stored leukocyte DNA from a community-based study of aging using realtime polymerase chain reaction analysis to determine mean TL in our modification of a method measuring the ratio of telomere sequence to single-copy gene sequence.
  
  
  METHODS
  A multiethnic community-based study of aging and dementia.
  
  
  METHODS
  One thousand nine hundred eighty-three subjects 65 years or older. Mean (SD) age at blood draw was 78.3 (6.9) years; at death, 86.0 (7.4) years. Median follow-up for mortality was 9.3 years; 190 (9.6%) developed incident dementia.
  
  
  RESULTS
  The TL was inversely related to age and shorter in men than women. Persons dying during follow-up had a shorter TL compared with survivors (mean [SD], 6218 [819] vs 6491 [881] base pairs [bp] [P.001]), even after adjustment for age, sex, education, and apolipoprotein E genotype. Individuals who developed dementia had significantly shorter TL (mean [SD], 6131 [798] bp for prevalent cases and 6315 [817] bp for incident cases) compared with those remaining dementia-free (6431 [864] bp). Cox-regression analyses showed that shorter TL was a risk for earlier onset of dementia (P=.05), but stratified analyses for sex showed that this association of age at onset of dementia with shorter TL was significant in women only.
  
  
  CONCLUSIONS
  Our findings suggest that shortened leukocyte TL is associated with risks for dementia and mortality and may therefore be a marker of biological aging.
authors: Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA. lh456@columbia.edu
authors: Lawrence S
authors: LS
authors: Honig
authors: Min Suk
authors: MS
authors: Kang
authors: Nicole
authors: N
authors: Schupf
authors: Joseph H
authors: JH
authors: Lee
authors: Richard
authors: R
authors: Mayeux
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001057:Apolipoproteins E / Q000235:genetics; D003704:Dementia / Q000235:genetics / Q000401:mortality / Q000473:pathology; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D012111:Residence Characteristics; D016019:Survival Analysis; D016615:Telomere / Q000378:metabolism*; D059506:Telomere Shortening / Q000235:genetics
chemical_list: D001057:Apolipoproteins E