Prospective analysis on the gut microbiome and the risk of autoimmune rheumatic diseases in the population-based FINRISK 2002 cohort

OBJECTIVES: To examine the long-term relationship between the gut microbiome and the risk of incident autoimmune rheumatic diseases (ARDs) in the general adult population. METHODS: Participants of the FINRISK cohort (N = 6,242) donated fecal samples in 2002 and were followed for incident ARD which was a composite outcome, defined as developing rheumatoid arthritis, ankylosing spondylitis, or systemic connective tissue disorder. We used multivariable-adjusted models to assess the association of incident ARD with alpha diversity, community composition, prevalent taxa, and prevalent predicted pathways. RESULTS: Incident ARD was observed in 264 (4.2%) participants over a median follow-up of 19.8 years. The top species detected in the multivariable-adjusted models were Scatocola faecipullorum, Sutterella wadsworthensis_A_565807, Alistipes_A_871404 indistinctus, and CAG-217 sp000436335. However, none of the associations reached statistical significance after FDR correction. Moreover, we did not find evidence of a statistically significant association between incident ARD and alpha diversity, community composition or prevalent predicted pathways in the age- and sex-adjusted or the multivariable-adjusted models. CONCLUSION: No evidence of association between baseline gut microbiome composition and the risk of incident ARDs (composite outcome) in the Finnish general adult population was detected in the current study. Our null findings, however, should be interpreted with caution since our study was limited by the use of a composite outcome (rather than using individual ARDs) and a single baseline measurement of the gut microbiome. More research efforts are still required to understand the prospective relationship between gut microbiome and individual ARDs.