One joint of marijuana worse than five cigarettes

It might give you a high, but smoking just one joint of cannabis or marijuana poses as much danger to the lungs as smoking up to 5 cigarettes in one go.

Washington, July 31 : It might give you a high, but smoking just one joint of cannabis or marijuana poses as much danger to the lungs as smoking up to 5 cigarettes in one go.

The finding is based on 339 adults up to the age of 70, selected from an ongoing study of respiratory health, and categorised into four different groups.

The first group comprised of those who smoked only cannabis, equivalent to at least one joint a day for five years; the second had those who smoked tobacco only, equivalent to a pack of cigarettes a day for at least a year; those who smoked both; and the third was made up of those who did not smoke either cannabis or tobacco.

All the participants had high definition x-ray scans (computed tomography) taken of their lungs and they took special breathing tests designed to assess how well their lungs worked.

They were also questioned about their smoking habits. 75 people smoked only cannabis, and 91 smoked both. 81 people did not smoke either, and 92 smoked only tobacco.

The researchers conducting the study found that cannabis smokers complained of wheeze, cough, chest tightness and phlegm.

And though emphysema, the progressive and crippling lung disease, was only seen in those who smoked tobacco, either alone or in combination, they found that cannabis still damaged the lungs and stopped them from working properly.

It diminished the numbers of small fine airways, which are important for transporting oxygen and waste products to and from the blood vessels effectively.

Cannabis smoking also damages the large airways of the lung, blocking airflow, and forcing the lungs to work harder.

The extent of this damage was directly related to the number of joints smoked, with higher consumption linked to greater incapacity.

The effect on the lungs of each joint was equivalent to smoking between 2.5 and five cigarettes in one go.

The authors explain that the impact of cannabis is strongly associated with the way in which it is smoked. It is usually smoked without a filter, and at a higher temperature. Smokers tend to inhale more deeply and to hold their breath for longer.

Combined smokers tended to use less tobacco, the findings showed.

The research is published ahead of print in the journal Thorax.

ANI