Table of Contents
ISRN Endocrinology
Volume 2013, Article ID 856017, 6 pages
http://dx.doi.org/10.1155/2013/856017
Review Article

A Clinical Review of the Association of Thyroid Stimulating Hormone and Cognitive Impairment

1Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
2Geriatric Department, Karolinska University Hospital Huddinge, Stockholm, Sweden

Received 29 June 2013; Accepted 26 August 2013

Academic Editors: Z. Bouizar and Z. Canturk

Copyright © 2013 Sylvia Annerbo and Johan Lökk. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Clinical and subclinical hypothyroidism as well as overt hyperthyroidism in middle-aged and elderly adults are both associated with decreased cognitive functioning as memory, reaction time, and visuospatial organization. Subclinical hyperthyroidism (SH) or low serum concentrations of TSH concentrations have been associated with dementia in previous epidemiological studies, but the association in the elderly has not been established. There is little or no consensus regarding how thyroid function is associated with cognitive performance in the elderly. In this focused review, we have performed an examination between eleven studies from the last five years examining the association between thyroid function and cognitive performance in elderly people, a group who is overrepresented among individuals with minor abnormalities in serum TSH and thyroid hormone concentration. Six of the studies showed a consistent finding of an association between SH with cognitive impairment or dementia. In general, taking into account the largest and most powerfully designed studies, there is a strong body of evidence supporting the association between SH and cognitive impairment. The scarce number of publications on these topics indicates the need of more research especially regarding longitudinal and interventional studies thus hopefully enabling confirmation or rejection of causality between TSH abnormalities and dementia.