title: Association between serum 25(OH) vitamin D and the risk of cognitive decline in older women.
abstract: BACKGROUND
  Results of prospective studies examining the association between 25 hydroxyvitamin D (25[OH]D) levels and cognitive decline have been inconsistent. We tested the hypothesis that lower 25(OH)D levels are associated with a greater likelihood of cognitive impairment and risk of cognitive decline.
  
  
  METHODS
  The study is a cross-sectional and longitudinal analysis of a prospective cohort of 6,257 community-dwelling elderly women followed for 4 years. Global cognitive function was measured by the Modified Mini-Mental State Examination and executive function was measured by Trail Making Test Part B (Trails B). Cognitive impairment at baseline was defined as a score >1.5 SD below the sample mean; cognitive decline was defined as decline from baseline to follow-up >1 SD from mean change in score.
  
  
  RESULTS
  Women with very low vitamin D levels had an increased odds of global cognitive impairment at baseline: odds ratio (95% confidence interval), 1.60 (1.05-2.42) for women with 25(OH)D <10 ng/mL (25 nmol/L) compared with those with 25(OH)D levels ≥30 ng/mL (75 nmol/L). Compared with women with baseline 25(OH)D level ≥30 ng/mL (75 nmol/L), women with lower levels had an increased risk of global cognitive decline: odds ratio (95% confidence interval), 1.58(1.12-2.22) for women with levels <10 ng/mL (25 nmol/L), and 1.31 (1.04-1.64) for those with levels 10-19.9 ng/mL (25-49 nmol/L). Levels of 25(OH)D were not associated with executive cognitive function.
  
  
  CONCLUSIONS
  Low 25(OH)D levels among older women were associated with a higher odds of global cognitive impairment and a higher risk of global cognitive decline.
authors.affiliation: Center for Chronic Disease Outcomes Research, VA Medical Center, Minneapolis, Minnesota, USA. slini001@umn.edu
authors.forename: Yelena
authors.initials: Y
authors.lastname: Slinin
authors.forename: Misti
authors.initials: M
authors.lastname: Paudel
authors.forename: Brent C
authors.initials: BC
authors.lastname: Taylor
authors.forename: Areef
authors.initials: A
authors.lastname: Ishani
authors.forename: Rebecca
authors.initials: R
authors.lastname: Rossom
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.forename: Terri
authors.initials: T
authors.lastname: Blackwell
authors.forename: Li-Yung
authors.initials: LY
authors.lastname: Lui
authors.forename: Marc
authors.initials: M
authors.lastname: Hochberg
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Ensrud
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood* / Q000523:psychology*; D003071:Cognition; D003072:Cognition Disorders / Q000097:blood / Q000209:etiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D056344:Executive Function; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D