Higher Vitamin D Levels Are Associated with Better Attentional Functions: Data from the NorCog Register.

The aim of this cross-sectional study was to evaluate which cognitive domains are mostly affected in persons with vitamin D insufficiency or deficiency, defined as 25(OH)D < 50 nmol/l and < 25 nmol/l, respectively. Data were collected from the Norwegian register for persons assessed for cognitive symptoms (NorCog). 580 persons aged ≥ 65 years were included. The following cognitive and neuropsychiatric tests were used: Mini Mental State Examination, Norwegian Revised Version (MMSE-NR), the Clock Drawing test, the Trail Making Test A and B, the 10-word memory test and the figure copying test from CERAD - immediate and delayed recall, The Controlled Oral Word Association Test -FAS and Boston Naming test. Neuropsychiatric symptoms were assessed by Neuropsychiatric Inventory-Questionnaire and Cornell Scale for Depression in Dementia. Vitamin D-insufficiency was found in approx. 30 % of the study cohort. After adjustment for relevant covariates, higher serum 25(OH)D levels were associated with higher score on MMSE-NR (p=0.032) and 10-word Memory Test, immediate recall (p=0.038), as well as faster execution of Trail Making Test A and B (p=0.038 and p=0.021, respectively). Other tests were not significantly associated with 25(OH)D levels. Higher vitamin D levels appear to be associated with better cognition, especially in areas of executive function and mental flexibility.

Déclaration de conflit d'intérêts

As potential conflicts of interest is to be mentioned that Anne-Brita Knapskog is the principal investigator in two drug trials (Roche BN29553 and Boehringer-Ingelheim 1346.0023) which are performed at the memory clinic, Department of Geriatric Medicine at Oslo University Hospital. The other authors declare no financial or other conflict of interest.