The association between subclinical thyroid dysfunction and dementia: The Health, Aging and Body Composition (Health ABC) Study.
Aubert CE., Bauer DC., da Costa BR., Feller M., Rieben C., Simonsick EM., Yaffe K., Rodondi N., Health ABC Study None.
OBJECTIVE: Data on the association between subclinical thyroid dysfunction and dementia are limited and conflicting. We aimed to determine whether subclinical thyroid dysfunction was associated with dementia and cognitive decline. DESIGN: Population-based prospective cohort study. PATIENTS: Adults aged 70-79 years with measured thyroid function, but no dementia at baseline, and Modified Mini-Mental State (3MS) at baseline and follow-up. MEASUREMENTS: Primary outcome was incident-adjudicated dementia, based on 3MS, hospital records and dementia drugs. Secondary outcome was change in 3MS. Models were adjusted for age, sex, race, education and baseline 3MS, and then further for cardiovascular risk factors. RESULTS: Among 2558 adults, 85% were euthyroid (TSH 0.45-4.49mIU/L), 2% had subclinical hyperthyroidism with mildly decreased TSH (TSH 0.10-0.44 mIU/L), 1% subclinical hyperthyroidism with suppressed TSH (TSH