title: Serum thyroid-stimulating hormone and cognition in older people.
abstract: BACKGROUND
  high TSH concentrations and cognitive decline are both very common among older people and could be linked.
  
  
  OBJECTIVE
  to assess cognition in our cohort of 335 home-dwelling older people (75 years and older) and to cross-sectionally relate the results to thyroid-stimulating hormone (TSH) concentrations. Our special focus was on the upper normal TSH range and subclinical hypothyroidism.
  
  
  METHODS
  cognitive performance was evaluated using the Consortium to Establish a Registry for Alzheimer's disease neuropsychological battery (CERAD-nb). The Clinical Dementia Rating (CDR) scale was used to evaluate severity of cognitive disorder. The APOEε4 genotype was also defined. Subjects were divided into quartiles based on the TSH concentrations, and results were compared between these groups.
  
  
  RESULTS
  expected relations were observed between CERAD domains and both educational level and APOEε4 genotype. Female sex significantly associated with better performance in Boston naming (OR = 0.48; 95% CI = 0.27-0.85). In the whole cohort, higher TSH concentrations tended to associate with better scores in most parts of the CERAD-nb tests, but differences were not statistically significant. However, subjects with the highest TSH concentration (90th TSH percentile, range 4.14-14.4 mU/l) had better CDR scores compared with subjects with the lowest TSH concentration (10th percentile, range 0.001-0.63 mIU/l; OR 0.10; 95% CI 0.014-0.76).
  
  
  CONCLUSIONS
  our results do not support the notion that higher TSH concentrations, not even in the range of subclinical hypothyroidism, would adversely affect cognition among older people.
authors.affiliation: Endocrinology, Abdominal Center, Helsinki University and Helsinki University Hospital, Helsinki FI-00290, Finland.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Ojala
authors.affiliation: Endocrinology, Abdominal Center, Helsinki University and Helsinki University Hospital, Helsinki FI-00290, Finland.
authors.forename: Camilla
authors.initials: C
authors.lastname: Schalin-Jäntti
authors.affiliation: Unit of General Practice, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Kaisu H
authors.initials: KH
authors.lastname: Pitkälä
authors.affiliation: Unit of General Practice, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Reijo S
authors.initials: RS
authors.lastname: Tilvis
authors.affiliation: Department of Medicine, Geriatric Clinic, University of Helsinki and Helsinki University Hospital, Helsinki, Finland Department of Public Health Science and General Practice, University of Oulu, Oulu, Finland.
authors.forename: Timo E
authors.initials: TE
authors.lastname: Strandberg
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000523:psychology; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D003071:Cognition; D003072:Cognition Disorders / Q000097:blood / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology; D003430:Cross-Sectional Studies; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000150:complications* / Q000175:diagnosis; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013972:Thyrotropin / Q000097:blood*; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D013972:Thyrotropin
keywords: TSH; cognition; older people