Thyroid dysfunction and risk of different types of dementia: A systematic review and meta-analysis.

Jianbo Ye, Zhenxing Huang, Chunfeng Liang, Zhang Yun, Lili Huang, Yuping Liu, Zuojie Luo

Journal: Medicine 2024;103(34):e39394

PMID: 39183422

Free Full Text on PubMed Central View on PubMed

Plain Language Summary

Dementia is characterised by memory loss and is particularly concerning as its prevalence is increasing and there is no known treatment. Prevention is therefore extremely important. Thyroid dysfunction has been shown to be associated with an increased risk for dementia and an understanding of why, may be of help with prevention. This systematic review and meta-analysis of 12 studies aimed to analyse the association between thyroid dysfunction and the risk for different dementia types. Associations between under-active thyroid function and a lower risk for Alzheimer’s disease and vascular dementia. Overactive thyroid function was associated with an increased risk for any dementia and vascular dementia. It was concluded that an under-active thyroid may decrease the risk for dementia and an overactive one, may increase it. This study could be used by healthcare professionals to understand that it may be important to measure an optimise thyroid function as part of a preventative measure in the development of dementia.

Abstract

BACKGROUND

The impact of thyroid function on the risk of various types of dementia, including Alzheimer's disease (AD) and vascular dementia (VD), remains unclear. This meta-analysis investigates the association between thyroid dysfunction and the risk of these dementia types, aiming to inform strategies for dementia prevention.

METHODS

A comprehensive search was conducted in PubMed, Embase, and the Cochrane Library for studies published up to February 2023, focusing on the risk of thyroid dysfunction in dementia. We excluded duplicates, studies without full text, those with incomplete data, animal studies, case reports, and reviews. Data analysis was performed using STATA 15.1 software.

RESULTS

Our analysis indicated that overt hyperthyroidism significantly increases the risk of all studied dementia types (OR = 1.18, 95% CI: 1.04-1.35). In contrast, overt hypothyroidism was associated with a decreased risk of AD (OR = 0.73, 95% CI: 0.55-0.98) and VD (OR = 0.71, 95% CI: 0.62-0.82). Subclinical hyperthyroidism also showed a significant association with an increased risk of any dementia (OR = 1.26, 95% CI: 1.09-1.46) and specifically VD (OR = 6.70; 95% CI: 1.38-32.58).

CONCLUSION

This study suggests that overt hypothyroidism may reduce the risk of dementia, including AD and VD, whereas overt and subclinical hyperthyroidism are linked to an increased risk. These findings highlight the importance of monitoring thyroid function as a preventative measure against dementia.

Address: Department of Endocrinology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.

DOI: 10.1097/MD.0000000000039394