This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
Objective: To study the role of thyroid function in dementia, cognitive function, and subclinical vascular brain disease with MRI.
Methods: Analyses were performed within the Rotterdam Study (baseline 1997), a prospective, population-based cohort. We evaluated the association of thyroid-stimulating hormone (TSH) and free thyroxine with incident dementia using Cox models adjusted for age, sex, cardiovascular risk factors, and education. Absolute risks were calculated accounting for death as a competing risk factor. Associations of thyroid function with cognitive test scores and subclinical vascular brain disease (white matter lesions, lacunes, and microbleeds) were assessed with linear or logistic regression. Additionally, we stratified by sex and restricted analyses to normal thyroid function.
Results: We included 9,446 participants with a mean age of 65 years. During follow-up (mean 8.0 years), 601 participants had developed dementia. Higher TSH was associated with lower dementia risk in both the full and normal ranges of thyroid function (hazard ratio [HR] 0.90, 95% confidence interval [CI] 0.83–0.98; and HR 0.76, 95% CI 0.64–0.91, respectively). This association was independent of cardiovascular risk factors. Dementia risk was higher in individuals with higher free thyroxine (HR 1.04, 95% CI 1.01–1.07). Absolute 10-year dementia risk decreased from 15% to 10% with higher TSH in older women. Higher TSH was associated with better global cognitive scores (p = 0.021). Thyroid function was not related to subclinical vascular brain disease as indicated by MRI.
Conclusions: High and high-normal thyroid function is associated with increased dementia risk. Thyroid function is not related to vascular brain disease as assessed by MRI, suggesting a role for thyroid hormone in nonvascular pathways leading to dementia.
GLOSSARY
- CES-D=
- Center for Epidemiologic Studies Depression Scale;
- CI=
- confidence interval;
- DSM-III-R=
- Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Revised;
- FT4=
- free thyroxine;
- HR=
- hazard ratio;
- IQR=
- interquartile range;
- RS=
- Rotterdam Study;
- TPOAb=
- thyroid peroxidase antibody;
- TSH=
- thyroid-stimulating hormone
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Supplemental data at Neurology.org
- Received February 3, 2016.
- Accepted in final form July 5, 2016.
- © 2016 American Academy of Neurology
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
Letters: Rapid online correspondence
REQUIREMENTS
If you are uploading a letter concerning an article:
You must have updated your disclosures within six months: http://submit.neurology.org
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
You May Also be Interested in
Use of Whole-Genome Sequencing for Mitochondrial Disease Diagnosis
Dr. Robert Pitceathly and Dr. William Macken
► Watch
Topics Discussed
Alert Me
Recommended articles
Depressed TSH level as a predictor of poststroke fatigue in patients with acute ischemic stroke
Favorable functional outcomes in acute ischemic stroke patients with subclinical hypothyroidism
Optimizing therapy of seizures in patients with endocrine disorders
Low thyroid-stimulating hormone as an independent risk factor for Alzheimer disease