Skip to content

Lung Disease & Respiratory Health Center

Font Size

Smoking Pot May Damage Lungs

Long-Term, Regular Use of Marijuana May Impair Airflow, Study Shows
By
WebMD Health News
Reviewed by Louise Chang, MD

July 31, 2007 -- Smoking pot regularly may, over time, damage the lungs, a New Zealand study shows.

The researchers included Richard Beasley, MBChB, of the Medical Research Institute of New Zealand in Wellington.

They studied 339 New Zealand adults, including 75 people who only smoked pot, 91 who smoked pot and tobacco, 92 who only smoked tobacco, and 81 who didn't smoke pot or tobacco.

Participants took lung function tests, urine tests, got high-tech lung scans using CT scanning, and completed surveys about their smoking habits.

All of the pot smokers had regularly smoked marijuana for at least five years. All of the tobacco smokers had smoked cigarettes for at least one year. Their urine tests confirmed their use of tobacco or marijuana.

Pot is illegal in New Zealand, so participants were promised total anonymity. Those who used other illegal drugs were excluded from the study.

Beasley's team wanted to find out whether long-term marijuana use was, like tobacco, associated with increased risk of emphysema. It wasn't.

However, long-term marijuana use was linked to lung problems including coughing, wheeze, chest tightness, and airflow obstruction.

Beasley's team calculates that, in terms of airflow obstruction, one marijuana joint equaled the effect of smoking 2.5 to five cigarettes at once. The finding is "of major public health significance," write the researchers.

The results are likely due to differences between tobacco cigarettes and marijuana joints, note the researchers.

"Cannabis is usually smoked without a filter and to a shorter butt length, and the smoke [has] a higher temperature," write Beasley and colleagues, adding that people inhale deeper and hold their breath longer when smoking marijuana.

The study appears in the advance online edition of the journal Thorax.

Today on WebMD

man coughing
You may not even know you have it.
blood clot
Signs of this potentially fatal complication.
 
man coughing
When a cold becomes bronchitis.
human lungs
Causes behind painful breathing, fluid buildup.
 

Bronchitis Overview
SLIDESHOW
Copd Myth Fact Quiz
QUIZ
 
Living With Copd
VIDEO
Energy Boosting Foods
SLIDESHOW
 

Pollen counts, treatment tips, and more.

It's nothing to sneeze at.

Loading ...

Sending your email...

This feature is temporarily unavailable. Please try again later.

Thanks!

Now check your email account on your mobile phone to download your new app.

cigarette butts snuffed out in ashtray
SLIDESHOW
Healthy Home Health Check
TOOL
 
Senior woman stretching
Article
Diagnosing Copd
VIDEO
 

WebMD Special Sections