Composition of Gut Microbes Can Predict & Improve Type 2 Diabetes: Study

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.