VOA常速英语2008年-New Study Links Smoking Marijuana to Gum Diseas

Recent studies show that cigarette smoking is one of the most significant factors leading to gum disease. And now, new research indicates smoking marijuana also promotes gum disease even for those who do not smoke cigarettes. VOA's Carol Pearson has more.

For decades, people in the United States -- and in some other countries as well -- have debated whether to legalize marijuana, or allow its use for medicinal purposes.

In the western U.S. state of California, patients in some areas can buy marijuana from a vending¹ machine.

Marijuana is known to ease some aches and pains, but a new study shows that habitual² use can lead to serious gum disease. Those most at risk? Young adults.

Murray Thomson and colleagues at a research institute in New Zealand examined roughly 900 young adults.

"When we were looking at the new cases of gum disease between 26 and 32, fully³ one-third of those new cases were due to cannabis smoking. That really surprised us," Thomson said.

They found even light users -- those who smoked marijuana once a week -- tripled their chances of getting gum disease over those who did not smoke pot. The increased risk held true even for those who did not smoke tobacco.

The researchers say toxins⁴ from marijuana destroy circulation and prevent the gums from being able to heal.

Periodontist Peter Cabrera says if you smoke marijuana, you may not even know you have serious gum disease until you start losing teeth, especially if you start smoking marijuana as a young adult. "So by the time you're in your 40s and 50s, you're likely to have lost a significant number of your teeth."

Gum disease also increases the risk of heart disease and stroke. And unless it is treated, gum disease will progress. This study was published in the Journal of the American Medical Association.