title: Cystatin C and cognitive impairment 10 years later in older women.
abstract: BACKGROUND
  Results of prospective studies examining the association between cystatin C and incident cognitive impairment have been inconsistent. We tested the hypothesis that there is a U-shaped association in older women between cystatin C and risk of incident cognitive impairment 10 years later.
  
  
  METHODS
  We conducted a longitudinal analysis of a prospective cohort of 1,332 community-dwelling elderly women without dementia at baseline who had baseline cystatin C and serum creatinine measurements and completed an extended cognitive battery of neuropsychological tests with determination of cognitive status 10 years later. Incident cognitive impairment was defined as either new onset of adjudicated diagnosis of mild cognitive impairment or dementia.
  
  
  RESULTS
  Incident mild cognitive impairment or dementia was identified among 140 (26.0%) women in quartile 1 (Q1), 122 (22.6%) in Q2, 121 (22.5%) in Q3, and 156 (28.9%) in Q4 of cystatin C. In the fully adjusted model, compared to women in Q2-Q3 of cystatin C, adjusted odds ratios (95% CI) for incident cognitive impairment were 1.31 (0.98-1.75) for Q1, and 1.25 (0.94-1.66) for Q4 Compared to women in Q2-Q3 of estimated glomerular filtration rate (eGFRCysC), adjusted odds ratios (95% CI) for incident cognitive impairment after 10 years of follow-up were 1.18 (0.88-1.58) for Q4 (eGFRCysC 76.1-109.4mL/min/1.73 m(2)) and 1.26 (0.94-1.67) for Q1 (eGFRCysC 21.8-55.5mL/min/1.73 m(2)).
  
  
  CONCLUSIONS
  These results support a U-shaped association between cystatin C concentration and risk of cognitive impairment or dementia 10 years later, but the association is not independent of potential confounding factors.
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis. Department of Medicine, Minneapolis VA Health Care System, Minnesota. slini001@umn.edu.
authors.forename: Yelena
authors.initials: Y
authors.lastname: Slinin
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco.
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Peters
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis. Department of Medicine, Minneapolis VA Health Care System, Minnesota.
authors.forename: Areef
authors.initials: A
authors.lastname: Ishani
authors.affiliation: Department of Psychiatry, Neurology, and Epidemiology & Biostatistics, University of California, San Francisco.
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis. Department of Medicine, Minneapolis VA Health Care System, Minnesota. Division of Epidemiology & Community Health and.
authors.forename: Howard A
authors.initials: HA
authors.lastname: Fink
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco.
authors.forename: Katie L
authors.initials: KL
authors.lastname: Stone
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis.
authors.forename: Michael
authors.initials: M
authors.lastname: Steffes
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis. Department of Medicine, Minneapolis VA Health Care System, Minnesota. Division of Epidemiology & Community Health and.
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Ensrud
mesh_terms: D000368:Aged; D000375:Aging; D060825:Cognitive Dysfunction / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D003704:Dementia / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008137:Longitudinal Studies; D009483:Neuropsychological Tests; D011446:Prospective Studies; D014481:United States / Q000453:epidemiology
chemical_list: D055316:Cystatin C; D003404:Creatinine
keywords: Aging.; Cognitive impairment; Cystatin C