Efficacy of Metformin for Benign Thyroid Nodules in Subjects With Insulin Resistance: A Systematic Review and Meta-Analysis

Background: To evaluate the effect of metformin therapy on decreasing benign thyroid nodule volume in subjects with insulin resistance (IR).Method: Randomized controlled trials (RCTs) and self-controlled trials for the meta-analysis published, before January 31, 2018 were selected from the PubMed, Cochrane Library, Embase, Web of Science, Chinese Biomedical Literature Database, National Knowledge Infrastructure, WANFANG and VIP Database. Pooled standard mean difference with 95% confidence interval was estimated by fixed- or random-effects model depending on heterogeneity. The risk of bias using the Cochrane Collaboration's tool was used to assess the quality of the RCTs contained. The quality of self-controlled studies was evaluated using the Methodological index for non-randomized studies (MINORS) method.Results: 7 studies (3 RCTs and 4 prospective self-controlled studies) with 240 patients were considered to be appropriate for the meta-analysis. The results of the meta-analysis indicated that the volume of thyroid nodule decreased significantly after metformin therapy (SMD −0.62, 95% CI −0.98 ~ −0.27). 6 studies reported the changes of the level of TSH. TSH levels decreased significantly after metformin therapy (SMD −0.27, 95% CI −0.47 ~ −0.07). The pooled data indicated an increase in FT3 level, and an unchanged FT4 level after metformin therapy (FT3, SMD 0.25, 95% CI 0.05 ~ 0.45; FT4, SMD −0.07, 95% CI −0.27 ~ 0.13). HOMA-IR levels decreased significantly after metformin therapy based on the pooled results of 3 RCTs and 3 prospective self-controlled studies (SMD −1.08, 95% CI −1.69 ~ −0.47).Conclusion: The meta-analysis demonstrated that metformin was safe and useful in shrinking benign thyroid nodules volume, improving thyroid function and IR. A large number of high-quality prospective studies still need to be carried out

Association between ADIPOQ +45T>G Polymorphism and Type 2 Diabetes: A Systematic Review and Meta-Analysis

Recently, a number of studies have reported the association between the single nucleotide polymorphisms (SNPs) +45T>G polymorphism in the adiponectin (ADIPOQ) gene and type 2 diabetes mellitus (T2DM) risk, though the results are inconsistent. In order to obtain a more precise estimation of the relationship, a meta-analysis was performed. In this current study, the Medline, Embase, Pubmed, ISI Web of Knowledge, Ovid, Science Citation Index Expanded Database, Wanfang Database, and China National Knowledge Infrastructure were searched for eligible studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of association. Forty-five publications were included in the final meta-analysis with 9986 T2DM patients and 16,222 controls for ADIPOQ +45T>G polymorphism according to our inclusion and exclusion criteria. The +45T>G polymorphism was associated with an overall significantly increased risk of T2DM (G vs. T: OR = 1.18, 95% CI = 1.06–1.32; The dominant model: OR = 1.18, 95% CI = 1.03–1.33; The recessive model: OR = 1.47, 95% CI = 1.20–1.78; The homozygous model: OR = 1.62, 95% CI = 1.25–2.09; Except the heterozygous model: OR = 1.11, 95% CI = 0.98–1.24). Subgroup analysis revealed a significant association between the +45T>G polymorphism and T2D in an Asian population. Thus, this meta-analysis indicates that the G allele of the ADIPOQ +45T>G polymorphisms associated with a significantly increased risk of T2DM in the Asian population

Selenium Supplementation for Autoimmune Thyroiditis: A Systematic Review and Meta-Analysis

Many studies have reported that selenium (Se) has a close relationship with autoimmune thyroiditis (AIT). The therapeutic effect of Se supplementation in AIT treatment remains unclear. The objective of the present study was to determine the efficacy of Se supplementation for the treatment of AIT. A structured literature search was undertaken to identify all randomized controlled trials conducted in patients with AIT receiving Se supplementation or placebo. Nine studies enrolling a total of 787 patients were included. The results showed that Se supplementation with duration 6 months significantly dropped the TPOAb titers but did not decrease the TgAb titers. Patients assigned to Se supplementation for 12-month duration showed significantly lower TPOAb titers and TgAb titers. Patients after Se supplementation had a higher chance to improve the mood or well-being compared with controls. Se supplementation is associated with a significant decrease in TPOAb titers at 6 and 12 months; meanwhile, the TgAb titers can be dropped at 12 months. After Se supplementation treatment, patients had a higher chance to improve the mood without significant adverse events