LIGHT POT SMOKING DOSEN'T CAUSE LUNG DAMAGE

Light to moderate marijuana smokers show no signs of lung damage, in
contrast to cigarette smokers, according to results of a study
conducted in the United States.

A report to be published Wednesday in the Journal of the American
Medical Association shows that, over a 20-year period, pot smokers
generally did not experience a loss in lung functioning. Many
actually had enhanced lung capacity, which one researcher involved in
the study speculated might come from the common practice of holding
one's breath after inhaling cannabis smoke to maximize its
intoxicating effects.

On the other hand, cigarette smokers were found to have less capacity
in the amount of air they could exhale, and also in the speed at
which they could empty the air from their lungs.

The study included more than 5,000 people in the U.S., who were
assessed between 1986 and 2006.

"Marijuana may have beneficial effects on pain control, appetite,
mood and management of other chronic symptoms," researchers from the
University of California, University of Alabama and Northwestern
University said in a statement. "Our findings suggest that occasional
use of marijuana for these or other purposes may not be associated
with adverse consequences on pulmonary function."

There was a decline in lung function found among pot smokers who were
using the drug as frequently as 20 times a month, but the median
usage rate among the marijuana smokers in this study was two to three
times a month. Tobacco smokers in this study at the mid-range smoked
eight to nine cigarettes a day.

Stefan Kertesz, a professor of medicine at the University of Alabama
who contributed to the study, said the low amount of marijuana
generally smoked by subjects in comparison to the tobacco quantities
is likely "crucial" to the findings. He said it remains inconclusive
whether the substances themselves differ in how harmful they are to
people's lungs.

"Tobacco smokers in this study are smoking what is really orders of
magnitude more tobacco than marijuana smokers are smoking marijuana," he said.

Kertesz said the study did not address possible links between
marijuana and fatal diseases such as lung cancer and cardiovascular
disease, which have been found to result from tobacco smoking.
However, he said past research has not shown connections between
marijuana and these diseases.