Syracuse (WSYR-TV) - Marijuana is an illicit drug, but increasingly common in the United States. It is also used legally by some patients for medical purposes.
Marijuana smoke contains many of the same elements that are in tobacco smoke. A new study looks at what effect marijuana use has on lung function.
“With tobacco, we found exactly what others have found - essentially a straight line decline in both airflow rates and in lung volumes the more people smoked tobacco,” said Dr. Stefan Kertesz of the University of Alabama.
Kertesz and co-authors say that, with marijuana use, the line is a bit different.
“The effects of marijuana change depending on how much a person has used it over their lifetime,” Kertesz said.
Researchers studied a database of more than 5,000 people in four American cities. These individuals reported marijuana and tobacco use for over 20 years. Their lung function was also measured several times during that period by using standard breathing tests.
“Up to moderate levels of marijuana use…by that we mean up to the amount a person would smoke if they had a joint a day for seven years…there is not a loss of air flow rate…there’s not a loss of lung volumes…in essence, marijuana doesn’t seem to behave like tobacco at those levels of use,” the doctor said. “However, as much higher levels of use that curve changes, our results at those higher levels of use were not statistically significant, but they certainly introduce the hint of harm at very high levels of use.”
Kertesz also points out that the increase in lung function was very small.
“The increase we saw was about 50 cc…and that’s roughly the size of a small juice can,” Kertesz said.
Researchers say the way people breathe when smoking marijuana – deep breaths, in and out – may have prepared them to do better on these tests and is not a sign that the lung tissue is healthier.
“It would be very incorrect to look at this study and say, ‘Wow, if I smoke marijuana, that’s going to improve my lung health,” Kertesz said. “We don’t view our study or changes in the lungs as being the central point that a person should think about in deciding whether to use a drug like marijuana.”
This research also points out that small increases in lung function with low to moderate marijuana use have been noted in other studies.