Smoking Marijuana Associated With Increased Risk for Gum Disease

Please note: only for journalists in New Zealand and Australia, this study will have an early embargo of 6 a.m. (NZDT) Wednesday, February 6.

Newswise — Regular use of marijuana (cannabis) in young adulthood is associated with periodontal (gum) disease, according to a study in the February 6 issue of JAMA.

Periodontal disease is one of the most common chronic diseases in adults, with inflammation that can extend deep into the dental tissues, causing loss of supporting connective tissue and possible loss of teeth. Tobacco smoking is recognized as the primary behavioral risk factor for the condition, and it is thought cannabis smoking may have a similar effect, according to background information in the article.

W. Murray Thomson, Ph.D., of the Dunedin School of Medicine, Dunedin, New Zealand, and colleagues conducted a study to determine whether cannabis smoking is a risk factor for periodontal disease. The study included 903 participants who were born in Dunedin in 1972 and 1973 and assessed periodically: cannabis use was determined at ages 18, 21, 26, and 32 years and dental examinations were conducted at ages 26 and 32 years. The most recent data collection (at age 32 years) was completed in June 2005. Three cannabis exposure groups were determined: no exposure (293 individuals, or 32.3 percent), some exposure (428; 47.4 percent), and high exposure (182; 20.2 percent). Some exposure was defined as an average of 1-40 occasions of cannabis use reported during the years assessed; high exposure as an average of 41 or more occasions of cannabis use during those years.

At age 32 years, 265 participants (29.3 percent) had one or more sites with 4 mm or greater periodontal combined attachment loss (CAL; loss of periodontal tissue), and 111 participants (12.3 percent) had one or more sites with 5 mm or greater CAL. New attachment loss between the ages of 26 and 32 years in the none, some, and high cannabis exposure groups was 6.5 percent, 11.2 percent, and 23.6 percent, respectively. After controlling for tobacco smoking (measured in pack-years), sex, irregular use of dental services, and dental plaque, compared with those who had never smoked cannabis, those in the highest cannabis exposure group had a 60 percent increased risk for having one or more sites with 4 mm or greater CAL; a 3.1 times greater risk for having one or more sites with 5 mm or greater CAL; and a 2.2 times increased risk for having new attachment loss.

Tobacco smoking was strongly associated with periodontal disease, but there was no interaction between cannabis use and tobacco smoking in predicting the condition's occurrence.

"The study's demonstration of a strong association between cannabis use and periodontitis experience by age 32 years indicates that long-term smoking of cannabis is detrimental to the periodontal tissues and that public health measures to reduce the prevalence of cannabis smoking may have periodontal benefits for the population," the authors write.

"Although definitively establishing the periodontal effects of exposure to cannabis smoke should await confirmation in other populations and settings, health promoters and dental and medical practitioners should take steps to raise awareness of the strong probability that regular cannabis users may be doing damage to the tissues that support their teeth."

(JAMA. 2008;299[5]:525-531. Available pre-embargo to the media at www.jamamedia.org)

Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Editorial: Destructive Periodontal Disease and Tobacco and Cannabis Smoking

In an accompanying editorial, Philippe P. Hujoel, Ph.D., of the University of Washington, Seattle, comments on the findings regarding cannabis use and periodontal disease.

""¦ Thomson and colleagues have reported findings indicating that smoking of tobacco and potentially cannabis are associated with evidence of destructive periodontal disease that can be detected in early adulthood, long before other smoking-related diseases such as diabetes, cardiovascular disease, and certain cancers become apparent. Given the high prevalence of dental care in the young population in the United States, the dental profession has an opportunity to detect the early clinical signs of unhealthy lifestyles, including potential drug abuse, and could play a role with physicians in addressing the challenges of reducing chronic noncommunicable diseases."

(JAMA. 2008;299[5]:574-575. Available pre-embargo to the media at www.jamamedia.org)

Editor's Note: Please see the article for additional information, including financial disclosures, funding and support, etc.