Smoking risks health by altering bacterial balance in mouth

Smokers, if you didn't have enough reasons to kick the butt, then a new study is giving you one more

The study led by NYU Langone Medical Center and its Laura and Isaac Perlmutter Cancer Center found that smoking drastically alters the oral microbiome, the mix of roughly 600 bacterial species that live in people's mouths.

The researchers say their analysis is the most comprehensive to date to examine the effects of smoking on the make-up and action of bacterial species in the human mouth based on precise genetic testing.

Recent work in the field links imbalances in microbial populations in the gut to such immune disorders as Crohn's disease, as well as to some gastrointestinal cancers. Experts estimate that more than three-quarters of oral cancers are tied to smoking, but it remains to be seen whether smoking-related microbial differences in the mouth contribute to disease risk.

Senior investigator Jiyoung Ahn said that the study is the first to suggest that smoking has a profound impact on the oral microbiome.

Ahn added that further experiments will be needed, however, to prove that these changes weaken the body's defenses against cancer-causing chemicals in tobacco smoke, or trigger other diseases in the mouth, lungs, or gut.

The investigators found that the oral microbiome of smokers differed significantly from that of people who had never smoked and those who had quit smoking. The team also found that the oral microbiome of smokers bounces back after they quit smoking, with all former smokers (who had not smoked for at least 10 years) showing the same microbial balance as nonsmokers.

The study is published online in the International Society for Microbial Ecology Journal.