Is there any association between gut microbiota and type 1 diabetes? A systematic review

INTRODUCTION: Type 1 diabetes (T1D) is the second most common autoimmune disease among children. There is evidence suggesting that dysbiosis of some gut colonizing bacteria are associated with the pathogenesis of T1D. However, these studies are still controversial and a systematic review was conducted to evaluate the association between gut microbiota and T1D. METHODS: A systematic search was carried out in Medline (Via Pubmed) and Embase from January 2000 to January 2019 for all original cross-sectional, cohort, case–control or nested case–control studies investigating the association between gut microbiota and T1D. RESULTS: Of 568 articles identified, 26 studies met the inclusion criteria. The total population study of these articles consists of 2600 children (under 18 years old) and 189 adults. Among the included studies, 24 articles confirmed the association between gut microbiota dysbiosis and T1D. The most common bacterial alterations in T1D patients included Bacteroides spp., Streptococcus spp., Clostridium spp., Bifidobacterium spp., Prevotella spp., Staphylococcus spp., Blautia spp., Faecalibacterium spp., Roseburia spp., and Lactobacillus spp. CONCLUSION: Our study showed a significant association between alterations in intestinal microbial composition and T1D; however, in some articles, it is not clear which one happens first. Investigation of altered gut microbiota can help in the early detection of T1D before seropositivity. Targeted microbiome modulation can be a novel potential therapeutic strategy.