The Association Between Smoking and Gut Microbiome in BangladeshOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study asked whether cigarette smoking is associated with the composition of the gut bacterial community. It analyzed stool samples in a cross-sectional design drawn from a larger arsenic-exposure cohort in Bangladesh. Microbial DNA was extracted from feces and sequenced using 16S rRNA gene sequencing. The team tested associations of both smoking status and smoking intensity with the relative abundance, or the presence versus absence, of bacterial taxa from phylum down to genus level.
Who was studied?
Participants were 249 adults selected from the Health Effects of Arsenic Longitudinal Study in Bangladesh. This was a human, population-based cross-sectional sample spanning a wide adult age range, including men and women. Participants were grouped by smoking behavior, comparing current smokers with never-smokers. The cohort was community-based rather than clinically ill, which lets the analysis isolate smoking-related differences in the fecal microbiome across levels of tobacco exposure.
What were the most important findings?
Bacteria along the Erysipelotrichi-to-Catenibacterium lineage were significantly more abundant in current smokers than never-smokers. The odds ratio was 1.91 (95 percent confidence interval 1.36 to 2.69) for the genus Catenibacterium. It was 1.89 for the family Erysipelotrichaceae, the order Erysipelotrichale, and the class Erysipelotrichi, with false-discovery-rate adjusted p values of 0.0008 to 0.01. Each of these taxa showed a dose-response relationship with smoking intensity. The presence of Alphaproteobacteria was also significantly greater in current smokers (odds ratio 4.85).
What are the greatest implications of this study?
The findings add human epidemiological evidence that smoking status, and especially heavier tobacco exposure, tracks with measurable shifts in gut bacterial composition. The dose-response pattern strengthens the case that the association is not incidental. Because the design was cross-sectional, it shows correlation rather than proof that smoking causes these microbial changes. The authors present this as an early step, noting that epidemiological studies of smoking and the gut microbiome had been lacking.