Exploring the Correlation between Tobacco Exposure and Human Intestinal Flora

Objective: To investigate whether there are differences in the intestinal flora of healthy people with different levels of tobacco exposure, and explore the effects of tobacco exposure on the intestinal flora. Methods: Fecal samples were collected from 80 volunteers, including 17 cases in the tobacco exposure group (Smoking Index > 400) (group A), 16 cases in the tobacco exposure group (Smoking Index < 400) (group B), 16 cases in the long-term second-hand smoke exposure group (group C), 14 cases in the smoking cessation group (more than 6 months) (group D) and 17 cases in the non-tobacco exposure group (group E). Each of the above fecal samples was analyzed by 16SrDNA, and OTU analysis and species annotation, Alpha diversity, Beta diversity, significance analysis of community structure differences were performed between groups. Results: Groups A, B and D were closer in intestinal flora composition, while groups C and E were closer in composition. There were no significant abnormalities in the richness, diversity and community distribution of the intestinal flora between the groups. At the Phylum level ， there were significantly differences between the some groups of Firmicutes and Proteobacteria (p < 0.05). At the Genus level, there were significantly differences between the different groups of Agathobacter , Blautia , f_Lachnospi-raceae_Unclassified, Roseburia , and Subdoligranulum (p < 0.05). Conclusions: Despite there were no clear differences were found in the diversity of intestinal flora in people with different levels of tobacco exposure so far, but the genus Blautia and Roseburia were inversely correlated with tobacco exposure, which is worth further exploring.