Gut microbiome composition is regulated jointly by the host genome, the colonic milieu and diet. Accumulating evidence indicates that bacteria in the human gut play a vital role in the pathophysiology of T2D and related traits with higher gut microbiome alpha diversity having a beneficial effect. A recent suggests that some bacterial species in the gut microbiome as being predictive of the development of type 2 diabetes. The study findings were published in the journal Diabetes Care on January 31, 2022.

Recently, several studies have reported a link between the gut microbiome composition and type 2 diabetes. Specifically, type 2 diabetes has been reported to be associated with lower relative abundances of butyrate-producing microbes and increases in various opportunistic pathogens. To further explore, Dr Matti O. Ruuskanen and his team conducted a study to examine the previously unknown long-term association between gut microbiome composition and incident type 2 diabetes in a representative population cohort.
The FINRISK study has been conducted in Finland to investigate risk factors for cardiovascular disease every 5 years since 1972. For this study, the researchers assessed the fecal samples from 5572 residents of Finland enrolled in the FINRISK study in 2002 when they were 24-74 years old. Altogether, 432 cases of incident diabetes occurred over the median follow-up of 15.8 years. They sequenced the samples using shotgun metagenomics. They further examined the associations between gut microbiome composition and incident diabetes using multivariable-adjusted Cox regression models. They first used the eastern Finland subpopulation to obtain initial findings and validated these in the western Finland subpopulation.
Key findings of the study:
Altogether, the researchers observed 432 cases of incident diabetes over the median follow-up of 15.8 years.
Upon analysis, they found that four species and two clusters were consistently associated with incident diabetes in the validation models.
The four species were
♦ Clostridium citroniae (hazard ratio [HR] 1.21),
♦ C. bolteae (HR 1.20),
♦ Tyzzerella nexilis (HR 1.17), and
♦ Ruminococcus gnavus (HR 1.17).
All four of the diabetes-associated taxa have been previously linked with other metabolic diseases and risk factors, such as obesity and fatty liver disease.
They noted that these positive associations mostly consisted of these same species (HR 1.18).
Cluster 1 contained C. citroniae, C. boltae, and R. gnavus along with Eggerthella lenta. While Cluster 5 contained T. nexilis with C. symbiosum and C. glycyrrhizinilyticum.
They found no association with type 2 diabetes was seen for C. symbiosum, C. glycyrrhizinilyticum and E. lenta in the two clusters.
The authors concluded, "We observed robust species-level taxonomic features predictive of incident type 2 diabetes over long-term follow-up. These findings build on and extend previous mainly cross-sectional evidence and further support links between dietary habits, metabolic diseases, and type 2 diabetes that are modulated by the gut microbiome. The gut microbiome can potentially be used to improve disease prediction and uncover novel therapeutic targets for diabetes."
For further information:
DOI: https://doi.org/10.2337/dc21-2358
Keywords: Gut Microbes, Clostridium citroniae, C. bolteae, Tyzzerella nexilis, Ruminococcus gnavus, type 2 diabetes, FINRISK study, Diabetes Care, Gut Microbiome.