title: Thyroid function in the euthyroid range and adverse outcomes in older adults.
abstract: BACKGROUND
  The appropriateness of current reference ranges for thyroid function testing in older adults has been questioned.
  
  
  OBJECTIVE
  This study aimed to determine the relationship between thyroid function tests within the euthyroid range and adverse outcomes in older adults not taking thyroid medication.
  
  
  METHODS
  US community-dwelling adults years of older (n = 2843) enrolled onto the Cardiovascular Health Study with TSH, free T4 (FT4), and total T3 concentrations in the euthyroid range.
  
  
  METHODS
  Incidence of atrial fibrillation, coronary heart disease, heart failure, hip fracture, dementia, and all-cause death were measured.
  
  
  RESULTS
  No departures from linearity were detected. Higher TSH was negatively associated (P = .03) and higher FT4 was positively associated (P = .007) with mortality. Higher FT4 was associated with atrial fibrillation (P < .001) and heart failure (P = .004). Compared with the first quartile, individuals with TSH in the fourth quartile had a 9.6 per 1000 person-year lower incidence of dementia (P < .05) and those with FT4 in the fourth quartile had higher incidences of atrial fibrillation, coronary heart disease, heart failure, and mortality (11.0, 8.0, 7.8, and 14.3 per 1000 person-years, respectively, all P < .05). Total T3 was not associated with any outcome.
  
  
  CONCLUSIONS
  Higher TSH and lower FT4 concentrations within the euthyroid range are associated with lower risk of multiple adverse events in older people, including mortality. This suggests tolerance for lower thyroid hormone levels in this age group. Clinical trials are needed to evaluate the risk-benefit profile of new thresholds for initiating treatment and optimal target concentrations for thyroid hormone replacement in older people.
authors.affiliation: Division of Endocrinology, Diabetes and Metabolism (A.R.C., K.W.), Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104; Department of Biostatistics (A.M.A.), University of Washington, Seattle, Washington ; Department of Mental Health (M.C.), Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205; Division of General Medicine (J.R.), University of California, Davis, Sacramento, California 95817; Cardiovascular Health Research Unit (B.M.P.), Departments of Medicine, Epidemiology and Health Services, University of Washington, Seattle, Washington 98101; and Group Health Research Institute (B.M.P.), Group Health Cooperative, Seattle, Washington 98101.
authors.forename: Anne R
authors.initials: AR
authors.lastname: Cappola
authors.forename: Alice M
authors.initials: AM
authors.lastname: Arnold
authors.forename: Kendra
authors.initials: K
authors.lastname: Wulczyn
authors.forename: Michelle
authors.initials: M
authors.lastname: Carlson
authors.forename: John
authors.initials: J
authors.lastname: Robbins
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Psaty
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000453:epidemiology*; D002423:Cause of Death; D003327:Coronary Disease / Q000175:diagnosis / Q000453:epidemiology*; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000453:epidemiology*; D006620:Hip Fractures / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D011379:Prognosis; D012016:Reference Values; D016019:Survival Analysis; D013960:Thyroid Function Tests / Q000592:standards*; D013961:Thyroid Gland / Q000502:physiology*