Depression in Patients with Subclinical Hypothyroidism: A Systematic Review and Meta-Analysis

Background Symptoms of subclinical hypothyroidism include depression, memory loss, myocardial contractility disorder, lipid metabolic disorder, and atherosclerosis. However, the relationship between subclinical hypothyroidism and depression has not been consistent. Therefore, the purpose of this study was to provide the scientific evidence for the relationship between subclinical hypothyroidism and depression. Methods This study was a meta-analysis of depression in subjects with subclinical hypothyroidism. The search engine of PubMed, EBSCO, ScienceDirect, and RISS was used to search the studies published since the 1990s. A total of 176 documents were retrieved from the literature search, and finally 10 studies were included in the analysis. Statistical analysis of effect sizes was performed using Comprehensive Meta-Analysis software version 2.2.064. Results Of the 10 studies, five studies reported that depression was associated with subclinical hypothyroidism. Two of these studies were on women and two were on the elderly. The effect size of depression in patients with subclinical hypothyroidism was 3.46 (95% confidence interval 0.20–0.74, P=0.001), and the subclinical hypothyroidism was significantly associated with depression. Conclusions This study showed that subclinical hypothyroidism is associated with depression. The results also suggest the need for regular screening of depressive symptoms of patients with subclinical hypothyroidism. Especially, elderly and women with subclinical hypothyroidism may be the main targets of depressive symptom.