Endocrinology Section, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy.
Endocrinology Unit, Garibaldi Hospital, Catania, Italy.
Front Endocrinol (Lausanne). 2023 Jul 24;14:1200372. doi: 10.3389/fendo.2023.1200372. eCollection 2023.
Hashimoto's thyroiditis (HT) is the most common autoimmune disease. HT may be associated with nonthyroidal autoimmune diseases, including celiac disease (CD) or other gluten-related conditions (GRC). In the last years, interest about gluten-free diet (GFD) has increased for its supposed extraintestinal anti-inflammatory effect; thus, many patients with HT initiate GFD on their own.
The aim of this meta-analysis is to examine all available data in literature about the effect of a GFD on TgAb, TPOAb, TSH, FT4, and FT3 levels in patients with HT and no symptoms or histology of CD.
The study was conducted according to MOOSE (Meta-analysis Of Observational Studies in Epidemiology). The search was performed on databases PubMed and Scopus. The last search was performed on 7 February 2023. Quality assessment was performed. Meta-analyses were performed using the random-effect model. Hedges' was used to measure the effect size (ES). Statistical analyses were performed using StataSE 17.
The online search retrieved 409 articles, and 4 studies with a total of 87 patients were finally included for quantitative analysis. The risk of bias was generally low. The mean period of GFD was almost 6 months. The meta-analyses showed reduction in antibody levels with ES: -0.39 for TgAb (95% CI: -0.81 to +0.02; = 0.06; ² = 46.98%) and -0.40 for TPOAb (95% CI: -0.82 to +0.03; = 0.07; ² = 47.58%). TSH showed a reduction with ES: -0.35 (95% CI: -0.64 to -0.05; = 0.02; ² = 0%) and FT4 showed an increase with ES: +0.35% (95% CI: 0.06 to 0.64; = 0.02; ² = 0%). FT3 did not display variations (ES: 0.05; 95% CI: -0.38 to +0.48; = 0.82; ² = 51%). The heterogeneity of TgAb, TPOAb, and FT3 data was solved performing sub-analyses between patients with or without GRC (TgAb = 0.02; TPOAb = 0.02; FT3 = 0.04) and only for FT3, performing a sub-analysis between patients taking and not taking LT4 ( = 0.03).
This is the first meta-analysis investigating the effect of GFD on HT. Our results seem to indicate a positive effect of the gluten deprivation on thyroid function and its inflammation, particularly in patients with HT and GRC. However, current lines of evidence are not yet sufficient to recommend this dietary approach to all patients with a diagnosis of HT.
桥本甲状腺炎（HT）是最常见的自身免疫性疾病。HT 可能与非甲状腺自身免疫性疾病有关，包括乳糜泻（CD）或其他与麸质相关的疾病（GRC）。近年来，人们对无麸质饮食（GFD）的兴趣增加，因为它具有假设的肠道外抗炎作用；因此，许多 HT 患者自行开始 GFD。
本荟萃分析旨在检查文献中关于 GFD 对 HT 患者甲状腺球蛋白抗体（TgAb）、甲状腺过氧化物酶抗体（TPOAb）、促甲状腺激素（TSH）、游离甲状腺素（FT4）和游离三碘甲状腺原氨酸（FT3）水平影响的所有可用数据，且这些患者没有 CD 的症状或组织学表现。
该研究按照 MOOSE（观察性研究的荟萃分析）进行。在 PubMed 和 Scopus 数据库中进行了检索。最后一次检索是在 2023 年 2 月 7 日进行的。对质量进行了评估。使用随机效应模型进行荟萃分析。使用 Hedges' 测量效应量（ES）。使用 StataSE 17 进行统计分析。
在线搜索共检索到 409 篇文章，最终纳入了 4 项共 87 例患者的研究进行定量分析。总体偏倚风险较低。GFD 的平均持续时间接近 6 个月。荟萃分析显示抗体水平降低，ES 值分别为：TgAb-0.39（95%CI：-0.81 至 +0.02； = 0.06； ² = 46.98%）和 TPOAb-0.40（95%CI：-0.82 至 +0.03； = 0.07； ² = 47.58%）。TSH 降低，ES 值为-0.35（95%CI：-0.64 至 -0.05； = 0.02； ² = 0%），FT4 升高，ES 值为+0.35%（95%CI：0.06 至 0.64； = 0.02； ² = 0%）。FT3 无变化（ES：0.05；95%CI：-0.38 至 +0.48； = 0.82； ² = 51%）。通过在有或没有 GRC 的患者之间进行亚组分析（TgAb = 0.02；TPOAb = 0.02；FT3 = 0.04），解决了 TgAb、TPOAb 和 FT3 数据的异质性问题，仅在服用和未服用 LT4 的患者之间进行了 FT3 的亚组分析（ = 0.03）。
这是第一项调查 GFD 对 HT 影响的荟萃分析。我们的结果似乎表明，无麸质饮食对甲状腺功能及其炎症有积极影响，特别是在 HT 和 GRC 患者中。然而，目前的证据还不足以推荐这种饮食方法用于所有诊断为 HT 的患者。
