Adding to the growing literature concerning the long-term effects of marijuana, a new study that monitored 1,037 New Zealand residents for 38 years has determined the only negative physical health consequence to really watch out for is bad gums and damage to the bone that supports the teeth.
For the study, scientists used "laboratory measures of physical health" and also had the participants self-report their own health. The scientists also factored in socioeconomic status, childhood health and if the participant used tobacco.
So while cannabis users had poor periodontal health, they also had lower body mass indexes, smaller waists and better high-density lipoprotein, or HDL, the good cholesterol. These results have led researchers to think that cannabis may have an impact on metabolism, but
On the other hand, tobacco users had worse metabolisms, along with poorer lungs and more inflammation than their fellow participants. Scientists theorize that that's due to tobacco smokers burning through several packs a day while marijuana smokers may smoke only a few joints a day.
A study that looked at only 15 years of pot smokers' lives found that there was no increased mortality rate in comparison to non-smokers.
"The answers with marijuana aren't exactly what we would have expected them to be, and this is a great example," Dr. Kevin Hill, an assistant professor of psychiatry at Harvard Medical School who commented on the study for JAMA Psychiatry, said, according to Time. "You need to be willing to change your mind on these issues."