2022-07-13 ブラウン大学
甲状腺機能低下症と呼ばれる高齢者は、認知症を発症するリスクが高い可能性があることが、新しい研究で明らかになった。甲状腺ホルモン補充薬を必要とする高齢者の場合、認知症を発症するリスクはさらに高くなることがわかった。
甲状腺疾患は、認知症の症状と関連している場合があり、治療によって回復する可能性がある。
<関連情報>
- https://www.brown.edu/news/2022-07-13/thyroid-dementia
- https://n.neurology.org/content/early/2022/07/06/WNL.0000000000200740
甲状腺疾患と認知症リスク:全国規模の人口ベースケースコントロールスタディ Thyroid Disorders and Dementia Risk: A Nationwide Population-Based Case-Control Study
Daniel R Wieland, Julia R Wieland, Han Wang, Yi-Huei Chen, Ching-Heng Lin, Jing-Jie Wang,Chien-Hsiang Weng
Neurology. Published July 6, 2022
DOI: https://doi.org/10.1212/WNL.0000000000200740
Abstract
Background and Objectives: Dementia has been gaining attention in aging societies and is estimated to affect 50 million adults globally in 2020, and 12% of the US population may develop a thyroid disorder in their lifetime. There have been limited studies investigating the correlation between thyroid disorder and dementia in the Asian population.
Methods: Our large nationwide population-based case-control study utilized the Taiwanese National Health Insurance Research Database. 7,843 adults with newly diagnosed dementia without a previous history of dementia or neurodegenerative disease between 2006 and 2013 were identified and included in our study. 7,843 adults without dementia diagnosis prior to the index date were age and gender matched as controls. Diagnosis of hyperthyroidism or hypothyroidism prior to the diagnosis of dementia or the same index date was identified. Results were obtained from logistic regression models and adjusted for sex, age, history of hypertension, diabetes, coronary artery disease, depression, hyperlipidemia, alcohol dependence syndrome, tinnitus, hearing loss, and radioactive iodine treatment.
Results: A total of 15,686 patients were included in the study. Both case and control groups were slightly predominantly female (4,066 [51.8%]). The mean (SD) age for those with dementia was 74.9 (11.3) years, and for those without dementia was 74.5 (11.3) years. Among patients aged 65 years or older, a history of hypothyroidism was associated with an increased risk of being diagnosed with dementia (aOR, 1.81; 95% Cl 1.14-2.87; p=0.011), which was an association not present in patients older than 50 years but younger than 65 years. We found that this association was most significant among patients aged 65 years or older with a history of hypothyroidism who received hypothyroidism medication (aOR, 3.17; 95% Cl 1.04-9.69; p=0.043).
Discussion: Our large-scale case-control study found that among people ≥ 65 years old, those with a history of hypothyroidism were associated with an 81% increased risk of having dementia and among those, there was an over 3-fold increased dementia risk with thyroid conditions that required thyroid hormone replacement treatment. Future well-controlled prospective longitudinal studies should be conducted to elucidate these potential mechanisms and relationships.
Classification of Evidence: This study provides Class III evidence that among patients aged 65 years or older, a history of hypothyroidism was associated with an increased risk of being diagnosed with dementia.
