Oral microbiome and history of smoking and colorectal cancerOriginal 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?
Researchers examined whether oral microbiome composition relates to smoking history and colorectal cancer history. Oral rinse DNA came from 190 participants in a population based case control study in the Detroit area, including 68 colorectal cancer cases.
How was it studied?
The V3 to V4 region of the bacterial 16S rRNA gene was amplified and sequenced on an Illumina MiSeq across two runs, yielding about 35 million filtered reads. Reads were classified from phylum down to species level and analyzed with negative binomial regression adjusted for age and experimental batch.
What did they find?
Colorectal cancer history was associated with roughly double the presence of one bacterial genus and a 28 percent increase in relative abundance of another taxon. Current smoking was linked to a 33 percent decrease in Betaproteobacteria, driven mainly by one dominant family, and a 23 percent increase in a different family. Smoking also significantly shifted principal component and principal coordinate scores without changing overall diversity or richness.
Why it matters
The study did not confirm a link between colorectal cancer and the oral pathogens most often implicated in prior reports. It suggests smoking reshapes oral bacterial community structure in ways that may serve as a marker of oral health, independent of overall microbial diversity.