title: Vitamin D is not associated with cognitive status in a cohort of very old hospitalized patients.
abstract: OBJECTIVE
  The association between vitamin D levels and cognitive function remains a controversial issue especially in the very old, highly comorbid patients. We address the relative contribution of vitamin D when taking into account potential confounders well known to be involved in cognitive decline.
  
  
  METHODS
  We investigated, in a prospective study of 428 very old inpatients from the Geneva geriatric hospital (mean age 85.2 y ± 6.8; 74.1% women), the association between 25-hydroxyvitamin D (25(OH)D) levels with dementia and mild cognitive impairment (MCI), taking into account comorbid conditions, functionality, malnutrition, ApoE genotype, vitamin B12, calcium, and albumin as independent variables.
  
  
  RESULTS
  25(OH)D level was not different between the cognitively normal (n = 200), MCI (n = 46), and demented (n = 182) patients nor between the different etiologies of dementia. In polytomous logistic regression, the 25(OH)D level neither as a continuous variable nor as a categorical variable increased the risk to be MCI or demented. The 25(OH)D level did not predict conversion from normal or MCI to dementia in the 315 subjects who completed the 2 years follow-up. No changes were observed in the full adjusted model after taking into account the independent variables. Similarly, considering only the group of cognitively normal subjects, the 25(OH)D level was not associated with impairment of specific cognitive domain.
  
  
  CONCLUSIONS
  In this cohort of old hospitalized patients with a high burden of comorbidities, the 25(OH)D level alone or adjusted for confounders is not associated with cognitive status and did not predict conversion to dementia.
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Christophe E
authors.initials: CE
authors.lastname: Graf
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Cécile
authors.initials: C
authors.lastname: Rossi
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Sandra V
authors.initials: SV
authors.lastname: Giannelli
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Bentolhoda Heyrani
authors.initials: BH
authors.lastname: Nobari
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Gold
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: François R
authors.initials: FR
authors.lastname: Herrmann
authors.affiliation: Department of Internal Medicine, Rehabilitation and Geriatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Dina
authors.initials: D
authors.lastname: Zekry
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000378:metabolism*; D015331:Cohort Studies; D003704:Dementia / Q000378:metabolism*; D005260:Female; D006760:Hospitalization; D006801:Humans; D016015:Logistic Models; D008297:Male; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D; Cognition; conversion; dementia; elderly; vitamin D