title: Thyroid hormones are associated with cognitive function: moderation by sex, race, and depressive symptoms.
abstract: BACKGROUND
  Recent evidence indicates that thyroid hormones may be closely linked to cognition among adults.
  
  
  OBJECTIVE
  We investigated associations between thyroid hormones and cognitive performance, while testing effect modification by sex, race, and elevated depressive symptoms (EDS).
  
  
  METHODS
  This cross-sectional study used extensive data from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study.
  
  
  METHODS
  The study was conducted in Baltimore, Maryland, from 2004 to 2009.
  
  
  METHODS
  PARTICIPANTS were U.S. adults aged 30 to 64 years. The sample size ranged from 1275 to 1346.
  
  
  METHODS
  Outcomes included 13 cognitive test scores spanning domains of learning/memory, language/verbal, attention, visuo-spatial/visuo-construction, psychomotor speed, executive function, and mental status.
  
  
  RESULTS
  Within reference ranges and after Bonferroni correction, elevated free thyroxine (fT4) was associated with better performance on tests of visuo-spatial/visuo-construction ability (overall, women, and African Americans) and learning/memory (women and African Americans), whereas a higher total thyroxine (tT4) level was associated with better performance in the domain of psychomotor speed (individuals without EDS) and higher levels of both fT4 and tT4 were linked to better language/verbal test performance among men. In contrast, higher T3(% uptake) was related to better performance on tests of visuo-spatial/visuo-construction ability and psychomotor speed among whites. When the above reference range was compared within the overall population and after Bonferroni correction, a within reference range fT4 was linked to better performance on visuo-spatial/visuo-constrution ability and psychomotor speed, whereas a below normal range TSH level (compared with the reference range) was linked to better performance in domains of psychomotor speed and attention.
  
  
  CONCLUSIONS
  Thyroid hormones and cognition are closely linked differentially by sex, race, and EDS status.
authors.affiliation: National Institutes of Health Biomedical Research Center, National Institute on Aging, Intramural Research Program, 251 Bayview Boulevard, Suite 100, Room 04B118, Baltimore, Maryland 21224, USA. baydounm@mail.nih.gov
authors.forename: M A
authors.initials: MA
authors.lastname: Beydoun
authors.forename: H A
authors.initials: HA
authors.lastname: Beydoun
authors.forename: M H
authors.initials: MH
authors.lastname: Kitner-Triolo
authors.forename: J S
authors.initials: JS
authors.lastname: Kaufman
authors.forename: M K
authors.initials: MK
authors.lastname: Evans
authors.forename: A B
authors.initials: AB
authors.lastname: Zonderman
mesh_terms: D000328:Adult; D001741:Black or African American; D003071:Cognition; D003430:Cross-Sectional Studies; D003863:Depression / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance; D012737:Sex Factors; D013963:Thyroid Hormones / Q000097:blood / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood
chemical_list: D013963:Thyroid Hormones; D013972:Thyrotropin