Marijuana exposure lacks ‘clear adverse effects’ on lungs, study says

The Coronary Artery Risk Development in Young Adults project studied 5,115 American men and women for more than 20 years and took measurements of pulmonary function. Adjustments were made with consideration to a subject’s age and other factors.

The group conducted the study to see if smoking marijuana had similar effects on the lungs to smoking tobacco.

Tobacco consumption causes “lung damage with clinical consequences that include respiratory symptoms, chronic obstructive pulmonary disease and lung cancer,” according to the study.

The CARDIA study reported that marijuana exposure occurred almost as often as tobacco exposure, but cited prior analyses that did not determine if marijuana had “clear adverse effects” on pulmonary function, even though it contains the “same constituents” as tobacco smoke.

Professor Michael Siegel, a tobacco expert at Boston University’s School of Public Health, said in a phone interview that while the study suggested smoking marijuana was less hazardous to pulmonary function than tobacco, it should not be concluded that there are no harmful effects.

“The level of marijuana use was relatively low,” he said, tapping into one of the faults of the study.

The marijuana users in the study only smoked two to three times, on average, within a 30-day period, a much lower level of exposure than the average tobacco smoker. The study states the number of heavy marijuana smokers was too small to make conclusions on high levels of marijuana exposure.

However, there is a chance that “very heavy” marijuana smokers would see negative effects on pulmonary function, according to the study.

Siegal said occasional, moderate use of marijuana, like alcohol, may not reveal the damaging effects.

Siegel also said that the 20-year timeframe was relatively short, and serious long-term effects, such as lung cancer, may not appear in a study period so brief.

He said there was a concern the study would “downplay the dangers of marijuana” by comparing it to tobacco.

Siegal said the study strengthens the idea that cigarette smoking is dangerous, but could diminish the public perception that marijuana is dangerous.

“The worst drug out there is tobacco,” he said.  “But marijuana is hazardous.”

The study, according to Siegal, supports medicinal marijuana because it shows moderate, short-term use of marijuana does not cause significant damage.

“Marijuana may have beneficial effects on pain control, appetite, mood and management of other chronic symptoms,” according to the CARDIA study.

Currently, medicinal marijuana is legal in 16 states and D.C., though according to the U.S. Drug Enforcement Administration, “smoked marijuana is not medicine,” a position the organization officially took in January 2011.

The U.S. Food and Drug Administration does not approve its use “for any condition disease.”

College of Communication sophomore Allison Thomasseau said she thought the study results were logical.

“Everything in moderation isn’t too terrible for you,” she said. “While smoking isn’t good for you, I think it’s alright as long as people are aware enough where it doesn’t take over their lives and change who they are.”