Smokers are more than 6 times more likely to develop gum disease than non-smokers but kicking the habit can prevent them from losing their teeth prematurely, researchers said on Monday.

Scientists at the University of Newcastle upon Tyne in England have shown that chronic gum disease in smokers significantly improves after they quit.

“Our study shows that people should stop smoking now if they want to increase their chances of keeping their teeth into old age,” said Dr Philip Preshaw, a specialist in gum disease who reported the findings in the Journal of Clinical Periodontology.

Smokers are more prone to chronic gum disease than non-smokers because the habit has a detrimental effect on the body’s immune system. Their bodies are less well equipped to fight the build up of bacteria in plaque that accumulates on the teeth.

The bacteria causes the gums to become inflamed, recede and bleed. In more severe cases of periodontal disease the gums recede and the bone that holds the teeth in place gradually erodes, so the teeth either fall out or need to be extracted.

“Dentists have known for some time that smokers have worse oral and gum health than non-smokers but for the first time we have shown that quitting smoking together with routine gum treatment results in healthier gums,” Preshaw added.

The researchers studied 49 smokers with chronic gum disease for a year. They noticed a significant improvement in the disease in the one fifth of smokers who quit, compared to those who did not.

About 15 million people in the United States alone suffer from gum disease, according to the Centers for Disease Control and Prevention in Atlanta, Georgia.

The risk of developing the illness increased with the number of cigarettes smoked daily.

In addition to increasing the odds of suffering from chronic gum disease, smoking is also the leading cause of lung cancer and other respiratory illnesses and a risk factor for Heart disease.

Researchers have also shown that smokers die, on average, 10 years earlier than non-smokers.