According to a study published in the JAMA Psychiatry, people who have smoked marijuana regularly for about 20 years show a greater risk for gum disease, but their other health symptoms are not worse than those of a non-smoker.

Details of the Study

This study was conducted by researchers from Duke University and King’s College in the UK; Arizona State University (ASU) in the U.S; and the University of Otago in New Zealand. Some of the research sponsors include the New Zealand Health Research Council, the US National Institute of Aging, and the UK Medical Research Council.

Duke University sent out a press release explaining that the research involved about 1,000 participants from New Zealand who were followed from birth until they turned 38 years old. The researchers were checking physical health factors such as: lung function, blood pressure, BMI (body mass index), systemic inflammation and cholesterol levels. Study participants were asked to describe their history of marijuana use, for instance, the age they started using the drug.

Surprisingly, researchers found that tobacco smokers suffered from reduced lung function, periodontal disease, systemic inflammation and poorer metabolic health, whereas, people who had smoked marijuana for about 20 years did not have different results from non-smokers.

Madeline Meier, an assistant professor of psychology at ASU, said, “We can see the physical health effects of tobacco smoking in this study, but we don’t see similar effects for cannabis smoking. We don’t want people to think, ‘Hey, marijuana can’t hurt me,’ because other studies on this same sample of New Zealanders have shown that marijuana use is associated with increased risk of psychotic illness, IQ decline and downward socioeconomic mobility.”

The press release also had quotes from study co-author Avshalom Caspi, the Edward M. Arnett Professor of psychology and neuroscience at Duke, who wrote, “What we’re seeing is that cannabis may be harmful in some respects, but possibly not in every way. We need to recognize that heavy recreational cannabis use does have some adverse consequences, but overall damage to physical health is not apparent in this study.”

Marijuana Use Causes Gum Disease

One of the notable conclusions from this study was that 55.6% of people who had smoked marijuana regularly for 20 years had gum disease. This result could not be explained by a failure of the user to brush their teeth properly or to floss every day. It also could not be explained by alcohol or tobacco abuse, or even by an individual’s healthy lifestyle.

According to Terrie Moffitt, the Nannerl O. Keohane University Professor of psychology and neuroscience at Duke and co-director of the Dunedin Multidisciplinary Health and Development Study, doctors can now point to a reason for people to be wary of marijuana.

He said, “Physicians should certainly explain to their patients that long-term marijuana use can put them at risk for losing some teeth.”

The National Institute of Dental and Craniofacial Research at the National Institutes of Health lists some of the symptoms of gum disease as: red, swollen and bleeding gums; tender and receding gums; tooth loss due to bone breakdown; bacterial infections; and bad breath.

Even as Americans continue the push for marijuana legalization using the popular phrase that it is a “safe drug”, perhaps looking at the results from this study will force a rethink on that stance.