L'ESTEREL, Quebec -- Heavy marijuana smokers show less evidence
of lung injury than heavy tobacco smokers, and it may be
cannabinoids that are protecting them from developing a condition
like emphysema.
That's according to the principal investigator of a study done at
the University of California at Los Angeles (UCLA).
Speaking at the third annual meeting of the International
Cannabis Research Society here, Dr. Donald Tashkin, a
pulmonologist and UCLA professor of medicine, concluded heavy
marijuana use did not cause the same degree of lung injury as
tobacco smoke.
His study, which aimed to measure the pulmonary effects of
habitual marijuana use, followed nine tobacco smokers, 10
marijuana smokers, 10 nonsmokers and four smokers of both
marijuana and tobacco. He gave both quantitative and qualitative
explanations for his finding.
Marijuana users in the study smoked three or four joints daily
for 15 years on average, while tobacco smokers in the study
smoked 25 cigarettes daily over a period of 20 years, indicating
a marked difference in exposure to smoke.
"There is a seven-fold difference in the amount of smoke to which
marijuana and tobacco smokers are exposed," he said.
"It's the quantitative difference in smoke exposure that might
explain the difference in the degree of lung injury as assessed
by these physiologic indices."
Moreover, the phagocytes gathered from the lungs of marijuana
smokers do not have the same properties as those gathered from
the lungs of tobacco smokers.