Thyroid function and cognitive health: rethinking the relationship between “suboptimal” TSH/FT4 levels and cognitive decline
No link was found between "suboptimal" thyroid function and cognitive impairment. Higher-normal TSH levels do not indicate dementia risk or hypothyroidism. Among participants with elevated TSH, 98.6% had normal FT4 levels. Redefining TSH cutoffs to 2.0 μIU/mL lacks clinical justification. Findings question the functional medicine approach of thyroid supplementation for cognitive health.
Authors
- Bruna Seixas Lima (ORCID: https://orcid.org/0000-0002-6747-8418)
- Carlos Roncero (ORCID: https://orcid.org/0000-0002-8712-0843)
- Michael Borrie
- Durjoy Lahiri (ORCID: https://orcid.org/0000-0002-2487-9537)
- Dvir Dori (ORCID: https://orcid.org/0009-0004-5332-3636)
- Howard Chertkow (ORCID: https://orcid.org/0000-0003-3749-8132)
Institutions
- Western University (CA)
- Island Health (CA)
- University of British Columbia (CA)
- University of Toronto (CA)
- Queen's University (CA)
- University of Victoria (CA)
- Baycrest Hospital (CA)
- Parkwood Institute (CA)
- Kingston Health Sciences Centre (CA)
Publication Details
- Journal
- Alzheimer s & Dementia
- Published
- 2025-12-01
- DOI
- https://doi.org/10.1002/alz.70960
- Primary Topic
- Thyroid Disorders and Treatments
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Consortium canadien en neurodégénérescence associée au vieillissement
- Canadian Institutes of Health Research