Subclinical Hypothyroidism: Mood, Cognition and the effect of L-thyroxine treatme

摘要 亚临床甲状腺功能减退症是一种生化诊断，其特征是 促甲状腺激素（TSH）水平与正常循环甲状腺素（T4）和三碘甲状腺原氨酸（T3） 程度.虽然SCH不存在临床甲状腺功能减退症的症状， 与情绪，认知和身体症状有关，并增加 高脂血症和缺血性心脏病。SCH还可能增加对以下疾病的脆弱性： 抑郁症、认知障碍和痴呆。SCH相对常见， 约占人口的5%至10%，患病率较高（高达20%） 在60岁以上的女性中。到目前为止，还没有设计良好的对照研究 评估了SCH对最脆弱人群的神经精神影响， 人口（即，老年人），以及甲状腺激素治疗在这方面的影响。 尽管甲状腺功能障碍和情绪之间存在着有据可查的联系， 和认知障碍这项建议的目的是评估抑郁症， 非痴呆老年SCH患者的神经心理功能， T4治疗在改善这些受试者的情绪和认知方面的功效。 拟议的研究分为两个阶段。在第一阶段，我们将采用交叉- 分段设计，以评估情绪，认知， 老年、非痴呆SCH受试者与 甲状腺功能正常对照。在第二阶段，我们将进行双盲，安慰剂- 对照的，16周的研究T4在改善这些措施中的作用， SCH受试者。情绪，认知，生活质量，甲状腺功能减退症的身体症状和 甲状腺状态（T4、T3、TSH和抗甲状腺过氧化物酶（抗TPO）抗体）将 测定了这项研究将产生关于神经精神影响的重要信息 SCH对易感人群的影响以及甲状腺激素治疗对 减轻症状并改善整体功能。项目叙述 该项目旨在确定是否有特定的情绪变化， 认知功能轻度甲状腺功能衰竭，也称为亚临床甲状腺功能减退症。 此外，本研究还将探讨情绪和认知的改变是否 与亚临床甲状腺功能减退症相关的甲状腺激素治疗改善。

Abstract Subclinical hypothyroidism is a biochemical diagnosis characterized by elevated thyrotropin (TSH) levels with normal circulating thyroxine (T4) and triiodothyronine (T3) levels. Although SCH does not present with symptoms of clinical hypothyroidism it may be associated with mood, cognitive, and physical symptoms, and increased risk for hyperlipidemia and ischemic heart disease. SCH may also increase vulnerability to depression, cognitive impairment, and dementia. SCH is relatively common and occurs in approximately five to ten percent of the population, with higher prevalence (up to 20%) in women over age 60. To date, there have been no well designed, controlled studies that have evaluated the neuropsychiatric effects of SCH on the most vulnerable population (i.e., elderly individuals), and the impact of thyroid hormone treatment in this group, despite the well documented association between thyroid dysfunction and mood and cognitive disturbance. The purpose of this proposal is to evaluate depression and neuropsychological function in non-demented, elderly individuals with SCH and the efficacy of T4 treatment in improving mood and cognition in these subjects. There are two phases to the proposed study. In phase I, we will employ a cross- sectional design to evaluate the specific nature, severity and pattern of mood, cognitive, and physical symptoms in elderly, non-demented participants with SCH compared with euthyroid controls. In the second phase, we will carry out a double-blind, placebo- controlled, sixteen week study of the effect of T4 in improving these measures in the SCH subjects. Mood, cognition, quality of life, physical symptoms of hypothyroidism and thyroid status (T4, T3, TSH and antithyroperoxidase (anti-TPO) antibodies) will be measured. This study will yield important information about the neuropsychiatric effects of SCH on a vulnerable population and the effect of thyroid hormone treatment in reducing symptoms and improving overall functioning. Project Narrative This project aims to determine whether there are specific alterations of mood and cognition with mild thyroid failure, also known as subclinical hypothyroidism. Furthermore, this research will also address whether alterations of mood and cognition associated with subclinical hypothyroidism are improved with thyroid hormone treatment.