Smoking a lot of pot can cause plenty of problems. Now a new study has found a new health risk: gum disease.
Researchers studied a group of more than 900 New Zealanders who smoked marijuana more than 40 times a year. They found that smoking that much pot regularly from the age of 18 greatly increased the chance of developing periodontal disease by age 32.
The study is published in the Journal of the American Medical Association.
It's well known that smoking tobacco can lead to gum disease, but no one had ever looked at whether marijuana has the same effect. The study measured how much gums receded at three sites on each tooth at ages 26 and again at 32.
The researchers found that those who reported the highest use of marijuana had triple the risk for severe gum disease and a 60 per cent higher risk for a milder form of it compared to people who had never smoked pot.
Even those who reported smoking pot fewer than 41 times a year were more likely to have mild and severe gum disease than people who never used the drug.
Most of the heavy pot users also smoked tobacco, but the researchers say they controlled for that statistically. When they focused on study participants who were not tobacco-users, they still found a link between marijuana use and gum disease.
The authors say the study adds to the understanding of the health effects of smoking marijuana.
"Heavy cannabis use has been linked to greater risks of developing respiratory disease and some psychiatric conditions," said Terrie Moffit, a Duke University professor of psychology and neuroscience who participated in the study.
"Gum disease should be added to that list of known hazards."
Gum disease is an infection of the tissues surrounding the teeth that causes the gums to shrink. In advanced stages, the gums and bone that support the teeth can become seriously damaged and the teeth can become loose and fall out.
It's not known exactly how smoking pot can lead to gum disease, but the researchers believe it interferes with immune function, inflammatory response and blood flow in the gums, just as tobacco does.
