Importance Hypothyroidism is considered a cause of or a strong risk factor for depression, but recent studies provide conflicting evidence regarding the existence and the extent of the association. It is also unclear whether the link is largely due to subsyndromal depression or holds true for clinical depression. Objective To estimate the association of hypothyroidism and clinical depression in the general population. Data Sources PubMed, PsycINFO, and Embase databases were searched from inception until May 2020 for studies on the association of hypothyroidism and clinical depression. Study Selection Two reviewers independently selected epidemiologic and population-based studies that provided laboratory or International Statistical Classification of Diseases and Related Health Problems diagnoses of hypothyroidism and diagnoses of depression according to operationalized criteria (eg, Diagnostic and Statistical Manual of Mental Disorders or International Statistical Classification of Diseases and Related Health Problems) or cutoffs in established rating scales. Data Extraction and Synthesis Two reviewers independently extracted data and evaluated studies based on the Newcastle-Ottawa Scale. Summary odds ratios (OR) were calculated in random-effects meta-analyses. Main Outcomes and Measures Prespecified coprimary outcomes were the association of clinical depression with either hypothyroidism or autoimmunity. Results Of 4350 articles screened, 25 studies were selected for meta-analysis, including 348 014 participants. Hypothyroidism and clinical depression were associated (OR, 1.30 [95% CI, 1.08-1.57]), while the OR for autoimmunity was inconclusive (1.24 [95% CI, 0.89-1.74]). Subgroup analyses revealed a stronger association with overt than with subclinical hypothyroidism, with ORs of 1.77 (95% CI, 1.13-2.77) and 1.13 (95% CI, 1.01-1.28), respectively. Sensitivity analyses resulted in more conservative estimates. In a post hoc analysis, the association was confirmed in female individuals (OR, 1.48 [95% CI, 1.18-1.85]) but not in male individuals (OR, 0.71 [95% CI, 0.40-1.25]). Conclusions and Relevance In this systematic review and meta-analysis, the effect size for the association between hypothyroidism and clinical depression was considerably lower than previously assumed, and the modest association was possibly restricted to overt hypothyroidism and female individuals. Autoimmunity alone may not be the driving factor in this comorbidity.

中文翻译：

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甲状腺功能减退症与临床抑郁症的关联：系统评价和荟萃分析。

重要性 甲状腺功能减退症被认为是抑郁症的原因或强烈的危险因素，但最近的研究提供了关于这种关联的存在和程度的相互矛盾的证据。还不清楚这种联系主要是由于亚综合征抑郁症还是适用于临床抑郁症。目的 评估一般人群中甲状腺功能减退症与临床抑郁症的关系。数据来源 PubMed、PsycINFO 和 Embase 数据库从开始到 2020 年 5 月都在搜索有关甲状腺功能减退症和临床抑郁症关联的研究。研究选择 两名审查员独立选择了流行病学和基于人群的研究，这些研究根据可操作的标准（例如，精神障碍诊断和统计手册或国际统计分类）提供疾病和相关健康问题的实验室或国际统计分类诊断甲状腺功能减退症和抑郁症诊断疾病和相关健康问题）或既定评级量表的截止点。数据提取和综合 两位评价员独立提取数据并根据纽卡斯尔-渥太华量表评估研究。在随机效应荟萃分析中计算总结比值比 (OR)。主要结果和措施 预先指定的共同主要结果是临床抑郁症与甲状腺功能减退症或自身免疫的关联。结果 在筛选的 4350 篇文章中，选择了 25 项研究进行荟萃分析，包括 348014 名受试者。甲状腺功能减退症与临床抑郁症相关（OR，1.30 [95% CI，1.08-1.57]），而自身免疫的 OR 尚无定论（1.24 [95% CI，0.89-1.74]）。亚组分析显示，与亚临床甲状腺功能减退症相比，与明显甲状腺功能减退症的相关性更强，OR 分别为 1.77（95% CI，1.13-2.77）和 1.13（95% CI，1.01-1.28）。敏感性分析导致更保守的估计。在一项事后分析中，该关联在女性个体中得到证实 (OR，1.48 [95% CI，1.18-1.85])，但在男性个体中未得到证实 (OR，0.71 [95% CI，0.40-1.25])。结论和相关性在本系统评价和荟萃分析中，甲状腺功能减退症和临床抑郁症之间关联的效应量比之前假设的要低得多，适度的关联可能仅限于明显的甲状腺功能减退症和女性个体。自身免疫本身可能不是这种合并症的驱动因素。