Smoking cannabis linked to respiratory problems

Smoking cannabis linked to respiratory problems

People who smoke cannabis as little as once a week are more likely to suffer respiratory symptoms such as morning cough, bringing up phlegm, and wheezing, according to University of Otago research.

However, the researchers' study into the long-term respiratory effects of found that after reducing or quitting cannabis smoking, these symptoms reduced to levels similar to those found in non-users.

In New Zealand, cannabis use is almost as widespread as tobacco with about half of young adults admitting to have used it in the previous year.

Associate Professor Bob Hancox, who led the study, says "Even people who only used cannabis once per week were likely to have a , bring up phlegm from the chest, and get wheezy. The good news is that if they stop smoking cannabis, these symptoms usually improve, although there was evidence that cough and wheeze may persist in those who have been long-term heavy users."

The effect of quitting cannabis use was studied in the Dunedin Multidisciplinary Health and Development Study, which continues to follow the progress of 1037 people born in Dunedin between April 1972 and March 1973. Cannabis and tobacco smoking histories were obtained at ages 18, 21, 26, 32 and 38 years. At each assessment, participants were asked how many times they had used the drug in the previous year.

Many cannabis users already had symptoms of bronchitis (cough, sputum production, and wheeze) by the age of 21 years. These symptoms persisted or got worse at ages 26, 32, and 38 years if people continued to use cannabis weekly or more. The association between cannabis use and bronchitis symptoms remained even after , asthma, and other factors were taken into account.

Dr Kyle Perrin, medical director at the Asthma Foundation says "Any form of smoking is going to affect your lungs. People who smoke marijuana, even if it is only once a week, need to realise that it will adversely affect their health."

"The findings indicate that cannabis users are likely to develop bronchitis but that this often gets better on quitting" says Associate Professor Hancox. "However, some people who had been heavy had a persistent cough and wheeze even after they cut down or quit. This suggests that long-term heavy may have lasting effects on the airways."

The findings appear in the European Respiratory Journal and the study was supported by the Asthma Foundation.


Explore further

What 20 years of research on cannabis use has taught us: review

Journal information: European Respiratory Journal

Citation: Smoking cannabis linked to respiratory problems (2015, May 19) retrieved 15 September 2019 from https://medicalxpress.com/news/2015-05-cannabis-linked-respiratory-problems.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
57 shares

Feedback to editors

User comments

May 19, 2015
My friend had no idea how much it was affecting his lungs until he switched to a vaporizer.

Turns out hot smoke into lungs isn't good for them! Who knew!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more