Apart from increasing the risk of lung cancer, smoking has also been found to increase the risk of oral disease as it kills off the good bacteria in the mouth.
Researchers from Ohio State University collected oral biofilms of 30 healthy participants, 15 of whom were regular smokers. The samples were collected two, four and seven days after professional cleaning.
The researchers found that the disease causing pathogens were largely absent in the mouths of non-smokers and the presence of cytokines was minimal, suggesting that the body was not considering the presence of healthy bacteria as dangerous.
Among the smokers group, the researchers found large presence of pathogens in the mouths within 24 hours of cleaning and also high levels of cytokines, readying the body to fight against the disease causing germs.
"The smoker's mouth kicks out the good bacteria, and the pathogens are called in. So they're allowed to proliferate much more quickly than they would in a non-smoking environment", lead researcher Professor Purnima Kumar said. The report has been published in the journal Infection and Immunity.