A new study finds that the development of bullous lung disease occurs in marijuana smokers approximately 20 years earlier than tobacco smokers.

A condition often caused by exposure to toxic chemicals or long-term exposure to tobacco smoke, bullous lung disease (also known as bullae) is a condition where air trapped in the lungs causes obstruction to breathing and eventual destruction of the lungs.

At present, about 10% of young adults and 1% of the adult population smoke marijuana regularly. Researchers find that the mean age of marijuana-smoking patients with lung problems was 41, as opposed to the average age of 65 years for tobacco-smoking patients.

The study "Bullous Lung Disease due to Marijuana" also finds that the bullous lung disease can easily go undetected as patients suffering from the disease may show normal chest X-rays and lung functions. High-resolution CT scans revealed severe asymmetrical, variably sized bullae in the patients studied. However, chest X-rays and lung functions were normal in half of them.

Lead author Dr. Matthew Naughton says, "What is outstanding about this study is the relatively young ages of the lung disease patients, as well as the lack of abnormality on chest X-rays and lung functions in nearly half of the patients we tested."

He added, "Marijuana is inhaled as extremely hot fumes to the peak inspiration and held for as long as possible before slow exhalation. This predisposes to greater damage to the lungs and makes marijuana smokers are more prone to bullous disease as compared to cigarette smokers."

Patients who smoke marijuana inhale more and hold their breath four times longer than cigarette smokers. It is the breathing manoeuvres of marijuana smokers that serve to increase the concentration and pulmonary deposition of inhaled particulate matter – resulting in greater and more rapid lung destruction.

This paper is published in the January 2008 issue of Respirology.