Feb. 6 (HealthDay News) -- Pot smokers face many of the same health consequences that tobacco users do, such as an increased risk of heart disease, but until now, it wasn't known that marijuana use could also destroy gum tissue.

In the Feb. 6 issue of the Journal of the American Medical Association, researchers reported that heavy marijuana users have as much as three times the risk of developing serious gum disease compared to those who haven't smoked pot.

"We found in our study that long-term heavy [marijuana] smokers had a greater risk of gum disease by the time they reach their early 30s," said study lead author W. Murray Thomson, a professor of dental epidemiology and public health at the Sir John Walsh Research Institute at the School of Dentistry in Dunedin, New Zealand.

"The gums in a person's oral cavity before the age of 35 seem to be a pretty sensitive marker for adverse lifestyles," said Philippe Hujoel, a professor in the department of Dental Public Health Sciences at the University of Washington School of Dentistry. Hujoel wrote an accompanying editorial in the same issue of the journal.

Marijuana is the most widely used illicit drug in the United States, according to the National Institute on Drug Abuse (NIDA). Smoked like tobacco, it has many similar ill health effects. Marijuana use has been associated with increases in the risk of heart disease, head and neck cancers, problems in the lungs and infection. Marijuana has also been associated with social behavior problems, according to NIDA.

For the study, Thomson and his colleagues used data from a group of 900 New Zealanders who have been followed from birth into their early 30s. The group members have been assessed 11 different times since they were 3 years old. The researchers began asking about marijuana use at age 18, and then again at 21, 26 and 32. Dental examinations were conducted at 26 and 32 years of age, according to the study.

Thomson acknowledged that it's sometimes difficult to get people to accurately report illicit drug use. But, he's confident in this case that the use of marijuana was honestly reported, because this group has been participating in this study for so long and knows that its answers will remain confidential.

The researchers identified three marijuana "exposure" groups: No exposure, 32.3 percent; some exposure, 47.4 percent; and high exposure, 20.2 percent.

After adjusting the data to account for tobacco use, gender and a lack of dental care, the researchers found that those in the high-use group had a 60 percent increased risk of early periodontal disease, a 3.1 times greater risk of more advanced gum disease, and a 2.2 times increased risk of losing a tooth due to gum disease, compared to those who didn't use marijuana.

"We think that it is the same as with tobacco smoke: That is, the effect is not directly on the gums as smoke is inhaled. Instead, it acts through toxins being absorbed into the bloodstream via the lungs and then affecting the body's ability to heal itself after bursts of destructive inflammation in the gums," Thomson said.

The bottom line, he said, is "don't smoke, whether it's cannabis or tobacco -- it's not a rational thing to do, and it has far-reaching effects on your health."

If you're concerned about the health of your gums, Hujoel suggested that you avoid risk factors, such as smoking, and ask your dentist or periodontist what additional steps you can take to protect them. If you have early periodontal disease, he said that regular periodontal maintenance care is generally recommended, but there may be other treatments, depending on your individual periodontal health.

SOURCES: Murray Thomson, Ph.D., professor of dental epidemiology and public health, Sir John Walsh Research Institute, School of Dentistry, Dunedin, New Zealand; Philippe Hujoel, Ph.D., professor in the department of Dental Public Health Sciences, School of Dentistry, University of Washington, Seattle; Feb. 6, 2008, Journal of the American Medical Association