A new study published in JAMA Psychiatry has found that the continued use of cannabis — even over the course of years or decades — has minimal effects on long-term health.

The study was conducted by a team of researchers led by Arizona State University’s Madeline H. Meier. It examined the effects of cannabis use among a select group of people over the course of 20 years.

Specifically, the study followed 1,037 New Zealanders for 20 years –from ages 18 to 38– and sought to determine whether there were any measurable changes in their physical health, particularly lung function, body weight, blood sugar, cholesterol levels, dental health, and blood pressure. The study also charted the effects of continued tobacco use.

Cannabis was found to have little to no effect on the body’s health, with the exception of users’ teeth: Cannabis users were found to have poorer periodontal health and were at greater risk of developing gum disease.

The study’s findings for cannabis users did not hold true for tobacco users. This group exhibited declining health in categories that went unaffected in users who stuck with cannabis.

By comparison, tobacco use was associated with worse periodontal health, lung function, systemic inflammation, high-density lipoprotein cholesterol levels, triglyceride levels, and glucose levels in early midlife, as well as health decline from ages 26 to 38 years.

The researchers were at a loss to explain why heavy cannabis users developed gum and teeth problems. While heavy cannabis users were found to have less regular flossing and brushing regimens than those who did not use the substance, even those who exhibited good dental hygiene were found to have poor dental health.

In general, our findings showed that cannabis use over 20 years was unrelated to health problems in early midlife… Across several domains of health (periodonal 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.

Past studies have indeed found associations between cannabis use and declines in health; however, unlike the study conducted by Meier and her team, the earlier studies charted changes in health at a single period in time, as opposed to over the course of many years.

Have you noticed a change in your dental health since you began using cannabis? Tell us about it on social media or in the comments below.