title: Vitamin D and cognitive functioning in the elderly population in Germany.
abstract: OBJECTIVE
  To examine the relationship of serum 25-hydroxy vitamin D3 with cognitive functioning in higher age, using an instrument covering multiple cognitive domains in a population-based study.
  
  
  METHODS
  Follow-up study with measurement of vitamin D levels at baseline and assessment of cognitive functioning at year 5 follow-up.
  
  
  METHODS
  A subgroup of 1639 participants of the ongoing epidemiological ESTHER study of the elderly general population in Saarland State, Germany, aged 65+ years at baseline (2000-2002).
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Cognitive functioning was assessed by the COGTEL phone interview developed by Kliegel et al., which was administered 5 years after ESTHER baseline. Vitamin D in baseline samples was measured by chemiluminescence methods. Additional information was obtained by standardised questionnaires.
  
  
  RESULTS
  In multiple linear regression adjusted for important confounders, women in the lowest sex-specific quintile of vitamin D showed an on average 2.1 (95% confidence interval: 0.4 to 3.9) units lower COGTEL score than women in the highest quintile. A similar, albeit slightly weaker, association was seen in males (difference of 1.7 [-0.4 to 3.8] units). Spline regression suggested non-linearity with a distinct decline in cognitive performance in the lower range of vitamin D levels.
  
  
  CONCLUSIONS
  Our findings support suggestions that low levels of vitamin D may be associated with reduced cognitive functioning in the elderly.
authors: Division C070 Clinical Epidemiology and Aging Research, German Cancer Research Center, Heidelberg, Germany. lutz.breitling@gmail.com
authors: Lutz P
authors: LP
authors: Breitling
authors: Laura
authors: L
authors: Perna
authors: Heiko
authors: H
authors: Müller
authors: Elke
authors: E
authors: Raum
authors: Matthias
authors: M
authors: Kliegel
authors: Hermann
authors: H
authors: Brenner
mesh_terms: D000368:Aged; D002762:Cholecalciferol / Q000172:deficiency*; D003072:Cognition Disorders / Q000453:epidemiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D012959:Socioeconomic Factors; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D002762:Cholecalciferol