Air pollution, gut microbiome, and metabolic markers in Bhopal, India: an exploratory ecological study
NOx correlated positively with glycemic indices in 95 urban adults in Bhopal; PM2.5 and PM10 showed no consistent directional associations with metabolic markers.
| Population | — |
|---|---|
| Intervention | — |
| Comparator | — |
| Outcome | — |
Context
Air pollution is an established cardiometabolic risk factor. The hypothesis that it reshapes the gut microbiome and thereby worsens T2D risk lacks data from South Asian urban populations.
What the study showed
NOx was positively associated with glycemic indices at the ecological level. Particulate pollutants showed inconsistent, non-directional associations with metabolic markers. Microbial community structures were broadly similar across the three sites, with only subtle differences in diversity and composition.
How it was done
Cross-sectional ecological study enrolling 95 participants from three urban localities in Bhopal. Air quality data came from locality-level monitoring stations, not individual personal monitors. Fecal microbiome was profiled with full-length 16S rRNA sequencing; exploratory correlation and compositional analyses were applied.
Risk of bias
Ecological design precludes causal inference and is susceptible to the ecological fallacy. Exposure was assigned at locality level, not individually measured. n=95 split across three sites limits power to detect subtle microbial differences. Analysis is based solely on the abstract; full data were unavailable.
What this study does NOT prove
The study does not prove that air pollution causes gut microbiome alterations or that such alterations mediate T2D risk.
In clinical practice
Findings do not support immediate clinical recommendations. Clinicians serving populations in high-pollution settings should maintain metabolic surveillance, but this study does not quantify individual-level risk.
Limitations
Ecological design precludes causal inference and is susceptible to the ecological fallacy. Exposure was assigned at locality level, not individually measured. n=95 split across three sites limits power to detect subtle microbial differences. Analysis is based solely on the abstract; full data were unavailable.
Technical appendix
Version history
- 1.0 · 2026-11-09 — Auto-generated under Evidence Standard v1.0