Smoking cannabis regularly can lead to gum disease in people in their early thirties – much younger than generally expected, according to a new study. Lifestyle factors associated with the condition are also linked to chronic diseases later in life, and some argue that gum disease itself may contribute to cardiovascular disease directly.

A quarter of people who had smoked cannabis regularly from 18 to 32 years old had established gum disease, found the study led by Murray Thomson at the Dunedin School of Dentistry in New Zealand.

In 2007, the same team showed that smoking tobacco also significantly raises the risk of gum disease in young people (Journal of Clinical Periodontology, vol 34, page 828)

In an editorial accompanying the current study (Journal of the American Medical Association, vol 299, page 574), Philippe Hujoel at the University of Washington in Seattle, US, suggests that dentists should treat the early signs of gum disease as “the canary in the coal mine” and use it to identify patients at risk of chronic diseases such as diabetes and heart disease.


‘Destructive effect’

Smoking and other lifestyle factors such as poor diet that are linked to gum disease, are also linked to chronic diseases like diabetes and cardiovascular disease that usually become apparent at a later age. Some experts even argue that gum disease may directly contribute to cardiovascular disease, although this remains controversial.

“You can see the destructive effect of smoking cannabis or tobacco much earlier than we thought you would. Dentists are the first witnesses of an adverse lifestyle. They are in a good position to give a physician referral or to talk about smoking cessation, which would benefit more than the oral cavity,” says Hujoel.

In the study, the Thomson team followed 903 people from 18 to 32 years old. They collected information about their use of cannabis at 18, 21, 26 and 32 years old, and did dental examinations at 26 and 32 years old.

Only 4% of the 400 people at age 32 who never smoked cannabis had gum disease – defined as having more than 5 mm of their gum detached from the tooth in at least one place in their mouth. Detachment of the gum, causes jaw bone to disappear, and – if untreated – teeth to fall out.

‘Big risks’

In contrast, 12% of the 428 people who smoked cannabis between 1 and 40 times a year, and 26% of the 182 people who smoked cannabis more than 40 times a year had gum disease at that age.

“A quarter of the people who had smoked cannabis regularly from 18 to 32 years old had established gum disease. We were surprised at how big the risks were,” says Thomson.

That increased risk existed even when the team took into account other factors such as tobacco smoking, sex (women tend to look after their teeth better), and the amount of plaque on the teeth – a good indicator of oral hygiene.

The moderate cannabis users still had over twice the risk of gum disease, and the heavy cannabis users three times the risk, compared with people who never smoked cannabis.

The findings contradict the common perception that gum disease happens in middle age, and is caused mainly by build up of plaque and poor dental hygiene rather than lifestyle, says Hujoel.

Journal reference: Journal of the American Medical Association (vol 299, page 525)

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