Format

Send to

Choose Destination
Neurology. 2016 Oct 18;87(16):1688-1695. Epub 2016 Sep 16.

Thyroid function and the risk of dementia: The Rotterdam Study.

Author information

1
From the Rotterdam Thyroid Center (L.C., T.I.M.K., R.P.P.) and Departments of Internal Medicine (L.C., T.I.M.K., R.P.P.), Epidemiology (L.C., F.J.W., D.B., T.I.M.K., A.H., O.H.F., A.D., M.W.V., R.P.P., M.A.I.), Neurology (F.J.W., P.J.K., M.A.I.), and Radiology (D.B., A.v.d.L., M.W.V., M.A.I.), Erasmus University Medical Center, Rotterdam, the Netherlands; and Department of Epidemiology (A.H.), Harvard T.H. Chan School of Public Health, Boston, MA.
2
From the Rotterdam Thyroid Center (L.C., T.I.M.K., R.P.P.) and Departments of Internal Medicine (L.C., T.I.M.K., R.P.P.), Epidemiology (L.C., F.J.W., D.B., T.I.M.K., A.H., O.H.F., A.D., M.W.V., R.P.P., M.A.I.), Neurology (F.J.W., P.J.K., M.A.I.), and Radiology (D.B., A.v.d.L., M.W.V., M.A.I.), Erasmus University Medical Center, Rotterdam, the Netherlands; and Department of Epidemiology (A.H.), Harvard T.H. Chan School of Public Health, Boston, MA. r.peeters@erasmusmc.nl.

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.

PMID:
27638924
DOI:
10.1212/WNL.0000000000003227
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center