Association Between Subclinical Thyroid Dysfunction and Cognitive Decline: Findings From the ELSA-Brasil Study.
J Gerontol A Biol Sci Med Sci
; 79(8)2024 Aug 01.
Article
in En
| MEDLINE
| ID: mdl-38953739
ABSTRACT
BACKGROUND:
Thyroid dysfunction has been associated with cognitive decline and dementia. However, the role of subtle thyroid hormone alterations in cognitive function is still debatable.METHODS:
Participants without overt thyroid dysfunction aged 35-74 years at baseline were evaluated in 3 study waves (2008-2010, 2012-2014, and 2017-2019). We assessed baseline thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3). Cognitive performance was evaluated every 4 years in each wave using 10-word immediate and late recall, word recognition, semantic (animals category) and phonemic (letter f) verbal fluency, and the trail-making B-version tests. A global composite z-score was derived from these tests. The associations of TSH, FT4, and FT3 levels with cognitive decline over time were evaluated using linear mixed-effect models adjusted for sociodemographic, clinical, and lifestyle variables.RESULTS:
In 9 524 participants (mean age 51.2â ±â 8.9 years old, 51% women, 52% White), there was no association between baseline TSH, FT4, and FT3 levels and cognitive decline during the follow-up. However, increase in FT4 levels over time was associated with faster memory (ß = -0.004, 95% CIâ =â -0.007; -0.001, pâ =â .014), verbal fluency (ß = -0.003, 95% CIâ =â -0.007; -0.0005, pâ =â .021), executive function (ß = -0.004, 95% CIâ =â -0.011; -0.003, pâ <â .001), and global cognition decline (ß = -0.003, 95% CIâ =â -0.006; -0.001, pâ =â .001). Decrease in FT4 levels over time was associated with faster verbal fluency (ß = -0.003, 95% CIâ =â -0.007; -0.0004, pâ =â .025) and executive function (ß = -0.004, 95% CIâ =â -0.007; -0.0003, pâ =â .031) decline.CONCLUSIONS:
An increase or decrease in FT4 levels over time was associated with faster cognitive decline in middle-aged and older adults without overt thyroid dysfunction during 8 years of follow-up.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Thyrotropin
/
Cognitive Dysfunction
Limits:
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Country/Region as subject:
America do sul
/
Brasil
Language:
En
Journal:
J Gerontol A Biol Sci Med Sci
Journal subject:
GERIATRIA
Year:
2024
Document type:
Article
Affiliation country:
Brazil