An international research team that conducted a study of 1,000 New Zealanders found that the people who smoked marijuana for up to 20 years were as healthy as non-smokers - with one exception.

They have a greater chance of suffering from gum disease.

The study, published in the journal JAMA Psychiatry, says cannabis consumers suffered from poor gum health, but it didn't negatively impact other areas of overall health.

"In general, our findings showed that cannabis use over 20 years was unrelated to health problems in early midlife," says the study. "Across several domains of health (periodontal health, lung function, systemic inflammation, and metabolic health), clear evidence of an adverse association with cannabis use was apparent for only one domain, namely, periodontal health."

But the same could not be said of tobacco smokers in the study, which looked at various other health measures including cholesterol levels, blood pressure, glucose control and body mass index. Tobacco users that took part in the study were also more vulnerable to gum disease, but also suffered from reduced lung function, systemic inflammation and indicators of poorer metabolic health.

"We can see the physical health effects of tobacco smoking in this study, but we don't see similar effects for cannabis smoking," said Madeline Meier, an assistant professor of psychology at Arizona State University who conducted the study with colleagues at Duke University, King's College in the UK and the University of Otago in New Zealand.

The study's authors don't understand how cannabis use negatively affects gum health, but patients should be forewarned of the possibility, says Terrie Moffitt - a Duke university professor and co-director of the Dunedin Multidisciplinary Health and Development Study, from which these data were gathered.

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

h/t The Washington Post.