INTRODUCTION Hypothyroidism has been implicated in many other disease conditions, including neurodegenerative diseases. Parkinson's disease (PD) is one of the most common neurodegenerative diseases. The purpose of this study was to investigate the risk of PD in patients with hypothyroidism. METHODS A total of 4725 patients with hypothyroidism and 4725 controls (without hypothyroidism) matched by age, gender, index year, and Charlson Comorbidity Index (CCI) score were enrolled between 2000 and 2012. Patients were then followed until the end of 2013 using Taiwan's National Health Insurance Research Database, at which time participants who developed PD were identified. Cox regression analysis was used to calculate the hazard ratio (HR) with a 95% confidence interval (CI) of PD incidence rate between patients with hypothyroidism and unaffected controls. RESULTS Patients with hypothyroidism had a significantly increased risk of PD compared with unaffected controls (2.00 versus 1.10 per 1,000 person-years, HR: 1.77, 95% CI: 1.13-2.76) after adjusting for age, gender, CCI score, physical comorbidities (brain injury, cerebrovascular disease, hypertension, dyslipidemia, and diabetes mellitus), and duration of levothyroxine use. Also, older age (≥50 vs. <50 - HR:14.83), higher CCI score (CCI score 1-2 & ≥3 vs. 0 - HR: 1.66-1.74), and specific comorbidities (brain injury (HR: 1.78) and cerebrovascular disease (HR: 2.46)) significantly increased the risk of PD after adjusting for the variables mentioned above. CONCLUSIONS Patients with hypothyroidism have an increased risk of developing PD. Other prospective studies that take into account genetic vulnerability and environmental exposures are warranted to confirm their relationship.

中文翻译：

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甲状腺功能低下患者帕金森氏病的风险：一项基于全国人群的队列研究。

简介甲状腺功能减退症与许多其他疾病有关，包括神经退行性疾病。帕金森氏病（PD）是最常见的神经退行性疾病之一。这项研究的目的是调查甲状腺功能减退症患者的PD风险。方法选取2000年至2012年之间按年龄，性别，指数年份和查尔森合并症指数（CCI）评分相匹配的4725例甲状腺功能减退患者和4725例对照（无甲状腺功能减退），然后随访患者直至2013年底。国家健康保险研究数据库，这时确定了PD的参与者。使用Cox回归分析来计算甲状腺功能减退症患者和未患病对照之间的PD发生率的危险比（HR）为95％置信区间（CI）。结果在调整了年龄，性别，CCI评分，身体合并症之后，甲状腺功能减退症患者的PD风险显着高于未受影响的对照组（每1000人年2.00比1.10，HR：1.77，95％CI：1.13-2.76）（脑损伤，脑血管疾病，高血压，血脂异常和糖尿病）以及使用左甲状腺素的持续时间。另外，年龄较大（≥50vs. <50-HR：14.83），较高的CCI评分（CCI 1-2和≥3vs. 0-HR：1.66-1.74）和特定的合并症（脑损伤（HR：1.78）调整上述变量后，）和脑血管疾病（HR：2.46）显着增加了PD的风险。结论甲状腺功能低下的患者发生PD的风险增加。考虑到遗传脆弱性和环境暴露的其他前瞻性研究也有必要确认它们之间的关系。