Pot Downer: Marijuana users risk gum disease

It’s a bummer, man.

Young adults who regularly smoke marijuana face an increased risk of severe gum disease, scientists report. The study is the first to link pot smoking to a health danger that’s more commonly associated with tobacco.

The findings arise from a long-term study of people born in the 1970s in Dunedin, New Zealand. Researchers there have monitored this group regularly, conducting periodic interviews about lifestyle and health and collecting data from medical exams. For this study, the scientists analyzed 903 people and noted the results from four dental checkups done between the ages of 18 and 32. These revealed any signs of periodontitis, an inflammation in which the inner layer of the gums and bone pull away from the teeth, ultimately loosening them. The researchers counted the number of spots in which gums had receded in each person and noted the severity of these detachments.

Meanwhile, the scientists assessed participants’ use of marijuana, also called cannabis. One-fifth of the people had smoked it about once a week in the years preceding two of the dental exams, while nearly half had smoked pot less often and 32 percent had never used it.

By the time they reached age 32, the heaviest cannabis users were three to five times as likely as the nonusers to have an area of severe gum detachment, the researchers report in the Feb. 6 Journal of the American Medical Association. Heavy users were also twice as likely to have incurred some of their periodontal damage between the ages of 26 and 32. Occasional pot smoking increased the risk somewhat less, says study coauthor W. Murray Thomson, a dentist at the University of Otago in Dunedin. The researchers accounted for tobacco use, socioeconomic status, frequency of dental services, and tooth plaque.

In a separate analysis, the team looked only at people who had never smoked tobacco. Those using only cannabis had dramatically more gum disease than non-smokers.

Gum tissues are soft but tough, designed to cling to the jawbones and teeth and hold everything in place. They also take a lot of abuse. Not only is the mouth a front line against invading pathogens, but gums often get nicked and cut from hard foods, says Scott Tomar, a dentist and epidemiologist at the University of Florida in Gainesville. For these reasons, gum health is a two-pronged affair: Invading pathogens must be cleared from the site by the immune system, and injured tissue must be repaired fast and often.

“Periodontitis is pretty widely thought to be a bacterial disease,” Tomar says. At the same time, chemicals in smoke also engender inflammation, which impairs the body’s ability to fight off bacterial infections and repair tissue.

While dentists routinely counsel patients against the periodontal risks of cigarette smoking, cannabis is a touchy subject, Tomar says. “You’re asking about an illegal behavior, so it does raise some discomfort among clinicians. On the other hand, here we have what may be a substantial risk for relatively young people,” he says. “It does have some very real clinical implications.”

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