Thyroid function, the risk of dementia and neuropathologic changes: the Honolulu-Asia aging study.
Thyroid dysfunction is associated with cognitive impairment and dementia, including Alzheimer's disease (AD). It remains unclear whether thyroid dysfunction results from, or contributes to, Alzheimer pathology. We determined whether thyroid function is associated with dementia, specifically AD, and Alzheimer-type neuropathology in a prospective population-based cohort of Japanese-American men. Thyrotropin, total and free thyroxine were available in 665 men aged 71-93 years and dementia-free at baseline (1991), including 143 men who participated in an autopsy sub-study. During a mean follow-up of 4.7 (S.D.: 1.8) years, 106 men developed dementia of whom 74 had AD. Higher total and free thyroxine levels were associated with an increased risk of dementia and AD (age and sex adjusted hazard ratio (95% confidence interval) per S.D. increase in free thyroxine: 1.21 (1.04; 1.40) and 1.31 (1.14; 1.51), respectively). In the autopsied sub-sample, higher total thyroxine was associated with higher number of neocortical neuritic plaques and neurofibrillary tangles. No associations were found for thyrotropin. Our findings suggest that higher thyroxine levels are present with Alzheimer clinical disease and neuropathology.
de Jong
Frank Jan
FJ
Department of Epidemiology & Biostatistics, Erasmus Medical Center, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. f.j.dejong@erasmusmc.nl
Masaki
Kamal
K
Chen
Hepei
H
Remaley
Alan T
AT
Breteler
Monique M B
MM
Petrovitch
Helen
H
White
Lon R
LR
Launer
Lenore J
LJ
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000453:epidemiology* / Q000473:pathology*; D001213:Asian / Q000235:genetics; D001921:Brain / Q000378:metabolism / Q000503:physiopathology*; D015331:Cohort Studies; D015897:Comorbidity; D018450:Disease Progression; D005500:Follow-Up Studies; D006254:Hawaii / Q000453:epidemiology; D006801:Humans; D008297:Male; D016874:Neurofibrillary Tangles / Q000378:metabolism / Q000473:pathology; D058225:Plaque, Amyloid / Q000378:metabolism / Q000473:pathology; D011446:Prospective Studies; D012307:Risk Factors; D013959:Thyroid Diseases / Q000453:epidemiology* / Q000503:physiopathology*; D013961:Thyroid Gland / Q000378:metabolism / Q000503:physiopathology*; D013974:Thyroxine / Q000097:blood / Q000378:metabolism; D013997:Time Factors
D013974:Thyroxine