Association Between Gut Microbiota and Autoimmune Thyroid Disease: A Systematic Review and Meta-Analysis

Abstract

BackgroundAutoimmune thyroid disease (AITD) is characterized by thyroid dysfunction and deficits in the autoimmune system. Growing attention has been paid toward the field of gut microbiota over the last few decades. Several recent studies have found that gut microbiota composition in patients with AITD has altered, but no studies have conducted systematic reviews on the association between gut microbiota and ATID.MethodsWe searched PubMed, Web of Science, Embase, and Cochrane databases without language restrictions and conducted a systematic review and meta-analysis of eight studies, including 196 patients with AITD.ResultsThe meta-analysis showed that the alpha diversity and abundance of certain gut microbiota were changed in patients with AITD compared to the controls. Chao1,the index of the microflora richness, was increased in the Hashimoto’s thyroiditis group compared to controls (SMD, 0.68, 95%CI: 0.16 to 1.20), while it was decreased in the Graves’ disease group (SMD, -0.87, 95%CI: -1.46 to -0.28). In addition, we found that some beneficial bacteria like Bifidobacterium and Lactobacillus were decreased in the AITD group, and harmful microbiota like Bacteroides fragilis was significantly increased compared with the controls. Furthermore, the percentage of relevant abundance of other commensal bacteria such as Bacteroidetes, Bacteroides, and Lachnospiraceae was increased compared with the controls.ConclusionsThis meta-analysis indicates an association between AITD and alteration of microbiota composition at the family, genus, and species levels.Systematic Review RegistrationPROSPERO, identifier CRD42021251557.

Hashimoto thyroiditis: an evidence-based guide: etiology, diagnosis and treatment

“…On the other hand, limited exposure to environmental factors, for example, living in almost sterile conditions, has also been associated with a high incidence of allergic and autoimmune diseases, including HT [22]. Microbiome composition has been associated with autoimmune thyroid disease with Bifidobacterium and Lactobacillus significantly decreased, and harmful microbiota such as Bacteroides fragilis significantly increased in HT as compared with control subjects without autoimmunity [23].…”

Deleterious Effect of Air Pollution on Human Microbial Community and Bacterial Flora: A Short Review

“…Healthy gut microbes regulate micronutrients such as iron, iodine, copper, zinc, and selenium essential for thyroid hormone synthesis [ 107 ]. Similarly, a meta-analysis showed the alteration of the gut microbiota composition is significantly associated with autoimmune thyroid disease [ 108 ].…”

Hashimoto’s Thyroiditis and Gut Microbiota

“…По данным результатов метаанализа работ, исследующих состояние МК при аутоиммунных заболеваниях щитовидной железы, индекс богатства видового сообщества микроорганизов (Chao1) был значительно повышен в образцах кала, взятых у пациентов с АИТ, что может быть связано с избыточным бактериальным ростом в кишечном тракте, при этом значительно увеличена относительная численность патогенных бактерий и снижена доля полезных бактерий, таких как Lactobacillus и Bifidobacterium, а увеличение количества видов B. Fragilis может объяснять активацию IL-18, IL-1β и каспазы-1, способствуя воспалительной реакции [21]. Показана положительная корреляция (p = 0,018) между Bacteroidetes и АТ-ТПО у пациентов с АИТ [20].…”