Gut Microbiota, Inflammaging and Future Disease Risk
Summary ID04-MB-RS-00069
Research Summary
Original Publication
Gut microbiota composition outperforms chronological age in predicting systemic inflammation and incident disease risk
Journal
Nature Communications, .
- Category
- 04Microbiome & Longevity
- Evidence
- Prospective Population-Based Cohort Study
- Summary Type
- Latest
What Was Studied?
Low-grade systemic inflammation tends to increase with age and is associated with many chronic diseases, including cardiovascular disease, type 2 diabetes and obesity. This age-related inflammatory state is often described as inflammaging.
However, people of the same chronological age can have very different levels of systemic inflammation. One possible contributor is the gut microbiota — the community of microorganisms living in the gastrointestinal tract.
Researchers investigated whether differences in gut microbiota composition were associated with systemic inflammation more strongly than chronological age and whether particular microbiota patterns were linked to future disease risk.
The study used data from the population-based Danish DanFunD cohort. The main integrated analysis included 1,199 adults aged approximately 20–72 years with paired gut microbiota and plasma cytokine measurements.
Researchers assessed:
* gut microbiota composition from fecal samples, * 30 circulating immune-related cytokines and inflammatory markers, * 19 biochemical and physiological measures related to metabolic and general health.
Future disease risk was assessed in 2,259 participants with available microbiota and smoking data, using Danish national health registers. Participants were followed for up to nine years, with an average follow-up of approximately eight years.
Several major microbiota-related inflammatory and metabolic findings were additionally examined in the independent MetaCardis cohort, which included 1,317 participants in the replication analyses.
Key Findings
Gut microbiota composition was more strongly associated with systemic inflammatory profiles than chronological age
Chronological age was associated with many inflammatory and physiological changes. Twelve cytokines increased with age, four decreased, and most biochemical and physiological measures were also age-related.
However, gut microbiota composition explained more variance than chronological age for 29 of 30 measured immune-related cytokines and inflammatory markers (97%).
It also explained more variance for 16 of 19 biochemical and physiological variables (84%), including body mass index, body fat, glucose, HbA1c, triglycerides and cholesterol measures.
Age explained more variance for only three of these 19 physiological variables: estimated cardiorespiratory fitness, systolic blood pressure and diastolic blood pressure.
These findings indicate that differences between individuals in gut microbiota composition were strongly associated with differences in systemic inflammatory and metabolic profiles beyond chronological age alone.
One microbiota pattern showed an inflammaging-like profile already in early adulthood
Researchers identified four major gut microbiota community patterns, or enterotypes: Bacteroides 1, Bacteroides 2, Prevotella and a high-diversity Richness enterotype.
Approximately 17% of participants had the Bacteroides 2, or B2, enterotype.
After adjustment for age, people with B2 had higher levels of several inflammatory markers, including IL-6, TNF-α and C-reactive protein (CRP).
They also tended to have a less favorable metabolic and physiological profile, including higher body mass index and triglycerides and lower HDL cholesterol and estimated cardiorespiratory fitness.
The combined pattern resembled inflammatory and metabolic changes usually associated with later adulthood.
Some inflammatory differences corresponded to age offsets of up to approximately 37 years
Based on modeled age-related trajectories, individuals with other enterotypes reached levels of certain inflammatory markers comparable to those observed in 20-year-old B2 individuals approximately 37 years later.
A similar pattern was observed for triglycerides.
This does not mean that people with the B2 enterotype were biologically 37 years older. The comparison refers specifically to modeled trajectories of selected inflammatory and metabolic markers.
Importantly, differences in several inflammatory cytokines became smaller with increasing age and largely converged across enterotypes by approximately age 65.
The Bacteroides 2 enterotype was associated with higher future disease risk
The researchers examined new hospital-associated diagnoses during up to nine years of follow-up.
People with the B2 enterotype had a 21% higher overall hazard of future incident disease compared with participants with the other enterotypes:
HR 1.21
The association extended across several disease categories, including circulatory, respiratory, digestive, nervous and musculoskeletal disorders, infections and eye disorders.
In contrast, participants with the high-diversity Richness enterotype had a 21% lower overall hazard of future disease:
HR 0.79
They also showed lower systemic inflammation and generally more favorable physiological profiles.
Systemic inflammation may partly connect microbiota patterns with disease risk
The researchers investigated whether inflammatory cytokines might statistically mediate the association between the B2 enterotype and subsequent disease.
The combined cytokine profile accounted for approximately 4.1% of the overall association with disease risk, although the estimated proportion differed between disease categories.
Mediation was greater for some outcomes, including respiratory and infectious diseases.
These findings support a possible pathway linking gut microbiota composition, systemic inflammation and subsequent disease risk.
However, mediation analysis in an observational study does not establish that the microbiota caused the inflammatory changes or subsequent disease.
Why It Matters for Longevity
Inflammaging is increasingly considered an important connection between biological aging and many chronic diseases.
This study suggests that the inflammatory environment associated with aging may differ considerably between people even at the same chronological age — and that the gut microbiota may be one factor associated with these differences.
This is particularly relevant for healthy aging because the microbiome is potentially modifiable through diet, lifestyle and, in the future, more targeted interventions.
But modifiable does not yet mean clinically proven as a treatment target.
Interventional studies are needed to determine whether deliberately changing microbiota composition can reduce systemic inflammation and ultimately lower disease risk.
The study therefore provides a strong rationale for further investigation of the gut microbiome–inflammation–disease pathway as part of the biology of healthy aging.
Clinical Perspective
This study provides important evidence that inflammaging varies substantially between individuals and cannot be explained by chronological age alone.
Gut microbiota composition was strongly associated with systemic inflammatory and metabolic profiles. Particularly notable was the presence of an inflammaging-like pattern in some younger adults, long before the age at which similar inflammatory profiles were typically observed in other participants.
The prospective health-register data strengthen the findings because the researchers were able to examine disease occurring after microbiota sampling rather than relying only on existing disease.
The replication of several microbiota-related inflammatory and metabolic associations in the independent MetaCardis cohort further supports the robustness of these findings.
However, this remains observational evidence.
The study does not demonstrate that changing a person’s microbiota will reduce systemic inflammation or prevent future disease. Diet and other lifestyle factors can influence both the microbiome and inflammatory health, and residual confounding cannot be excluded.
The enterotypes should also not be interpreted as fixed biological categories or as clinical diagnostic tests.
Key Takeaway
In a large population-based study, gut microbiota composition was more strongly associated with systemic inflammation than chronological age and was also linked to future disease risk. These findings suggest that the gut microbiome may play an important role in inflammaging, although its causal contribution to disease risk remains unproven.
Reviewed and Summarized by
Source Publication
- Title:
- Gut microbiota composition outperforms chronological age in predicting systemic inflammation and incident disease risk
- Authors:
- Carsten Eriksen, Ioanna Chatzigiannidou, et al.
- Journal:
- Nature Communications, September 2026.
