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Young people who are heavy smokers of cannabis may be putting themselves at significant risk for periodontal disease, according to new research.

The study, published in the Feb. 6 issue of the Journal of the American Medical Association, is believed to be the first to explore whether or not smoking a substance other than tobacco – in this case, marijuana more than other cannabis products – may be a risk factor for gum disease.

After controlling for tobacco smoking, gender, socioeconomic status and infrequent trips to the dentist by one-third of the participants, the study reported a “strong association between cannabis use and periodontitis experience by age 32.”

Study participants who reported the highest use of cannabis were 1.6  times more likely to have at least one gum site with mild periodontal disease – compared to those who had never smoked cannabis.

This group’s risk of having at least one site with more severe gum disease was estimated to be more than three times higher than the group who never used the substance.

Researchers defined the group of heavy cannabis users as participants who reported an average of 41 or more occasions of substance use per year between ages 18 and 32, equivalent to smoking the substance almost once a week through that period.

But people who reported even some cannabis (fewer than 41 times a year) were more likely to have mild and severe gum disease than people who never used the drug.

“In the United States, we think about periodontal disease as being a problem after the age of 35,” said James D. Beck, Ph.D., Kenan professor of dental ecology at the University of North Carolina at Chapel Hill School of Dentistry. “These findings, that almost 30 percent of individuals at age 32 had periodontal disease, indicate that this younger group may need more attention.”

The 903 participants are part of a longitudinal study of a group of children born at Queen Mary Hospital in Dunedin, New Zealand, between 1972 and 1973. The recent study’s senior author is W. Murray Thomson, Ph.D., a professor of dental public health at the Sir John Walsh Research Institute at the University of Otago’s School of Dentistry, in Dunedin.

Study participants received dental examinations at age 26 and a similar examination at age 32, and they gave self-assessments at ages 18, 21, 26 and 32 on their cannabis use during the previous year. In an effort to control for tobacco use, participants reported their tobacco use during four periods: up to age 18, ages 18 through 21, ages 21 through 26 and ages 26 to 32.

The study suggests that the benefits of public health measures to reduce the prevalence of cannabis use may carry over to gum disease. Additionally, researchers wrote, studying a possible association between cannabis use and periodontal disease in other populations “should be a priority for periodontal epidemiological research.”

Other study authors were Richie Poulton, Ph.D., David Welch, Ph.D., and Dr. Robert J. Hancox, all of the department of preventive and social medicine, Dunedin School of Medicine, the University of Otago; Jonathan M. Broadbent, the department of oral sciences, University of Otago; and Terrie E. Moffitt, Ph.D., and Avshalom Caspi, Ph.D., with the Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King’s College London, and with the departments of psychology and neuroscience, psychiatry and behavioral sciences and the Institute for Genome Sciences and Policy, Duke University.

Funding was provided by the National Institute of Dental and Craniofacial Research and the National Institute of Mental Health, both components of the National Institutes of Health; the Medical Research Council of the United Kingdom; and the Health Research Council of New Zealand, which supports the Dunedin Multidisciplinary Health and Development Research Unit.

Note: To schedule an interview with Dr. James D. Beck, contact Deb Saine at (919) 966-8512 or This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

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