POT SMOKING NOT SO HARMFUL TO LUNGS, STUDY FINDS

Smoking a joint from time to time won't damage the lungs, even after
years of drug use, according to a study led by UCSF researchers that
disproves one of the major concerns about marijuana - that smoking it
must be just as risky as lighting up a cigarette.

The study, results of which were published Tuesday in the Journal of
the American Medical Association, found that the lung capacity of
people who smoked marijuana was not diminished by regular toking, even
among those who smoked once or twice a week.

Only heavy marijuana users - those who smoked 20 or more joints a
month - saw a negative impact on the pulmonary system, but that level
of marijuana use is unusual, researchers said. In fact, they said, it
may be that marijuana smoke doesn't affect lung function the way
tobacco does simply because people don't smoke as many joints as they
do cigarettes.

The results should reassure doctors and patients who are considering
using marijuana for medical care, primarily to ease pain and nausea,
said Dr. Mark Pletcher, a UCSF epidemiologist and lead author of the
study.

But that's not to say that Pletcher or his colleagues are ready to
give the all clear to anyone who wants to smoke pot.

'Issue with marijuana'

"This study shouldn't be interpreted as marijuana is totally
harmless," said Dr. Stephen Sidney, a study author with Kaiser
Northern California's division of research in Oakland. "We don't see
marijuana having a big impact on lung function or lung disease. But it
doesn't mitigate the fact that we have an issue with marijuana, at
least in terms of dependence on it."

Smoking cigarettes has such dramatic, long-term health consequences -
including emphysema and lung cancer - that doctors have long assumed
that marijuana smoking, too, must be detrimental.

Heavy marijuana use may indeed turn out to be just as risky as
cigarette smoking, but that will be tough to prove because so few
people smoke as much pot as they do tobacco. And not all scientists
are convinced that marijuana smoke is actually as deadly as cigarette
smoke.

"No one would ever claim that drinking water has the same effect as
drinking vodka, even though they're both liquids and you're ingesting
them the same way," said Amanda Reiman, a UC Berkeley lecturer and
director of research at the Berkeley Patients Group, a medical
marijuana dispensary. "But for some reason we have assumed that
because we know the negative outcomes with cigarettes, inhaling any
plant material is going to have the same outcomes.

"This study is challenging the preconceived notions we've had for some
time about the dangers of smoking cannabis and the similarities to
smoking tobacco," she said.

Occasional users

For occasional users, smoking marijuana was actually associated with a
small but statistically significant increase in lung capacity,
according to the UCSF study. That increase wouldn't be noticeable to
the individual - and certainly shouldn't be interpreted as a
beneficial effect of smoking marijuana, scientists added - but it may
be related to the deep breathing pot smokers use to draw the drug into
their lungs.

The study looked at 5,115 men and women over a 20-year period,
starting in 1985, who were part of a national clinical trial meant to
look at heart disease risk in young adults. The smoking researchers
used data collected on tobacco and marijuana use, along with regular
tests of pulmonary function.

Pot and cigarettes

Study participants were just about as likely to smoke marijuana as
cigarettes, and many participants smoked both. People who smoked
cigarettes, however, were more likely to be heavy users - on average
about eight cigarettes a day - than marijuana smokers, who lit up on
average two or three times a month. The study lumped together all
types of inhaled marijuana use, meaning researchers did not
differentiate among those who smoked joints or pipes or any other implement.

The researchers noted that while most marijuana smokers may not
experience long-term lung problems, they may still suffer from coughs
and other temporary, relatively minor irritations to the throat and
lungs.

Dr. Stephen Ruoss, a Stanford pulmonologist who was not involved with
the study, was quick to note that while the results may show that
smoking pot isn't terrible for the lungs, that's hardly a robust
endorsement for getting stoned.

"If you inhale the smoke of a combustible organic material - either
tobacco leaf or marijuana leaf - is that a good thing for your lungs?
The safe answer is no," Ruoss said. "The hunch is that the more you
smoke, the greater the detrimental effect on your lung function. Even
with marijuana."

Longtime pot smoker

But Oakland resident La Wanda Martin, 44, said she's always assumed
that smoking marijuana was safer than smoking tobacco. She's been
smoking pot for more than 30 years, in part to treat back pain and
anxiety. She is currently lighting up several joints a day, which she
buys from Oaksterdam University, a cannabis industry training school.

"Cigarettes are worse to use," Martin said. "When you buy from a
cannabis club, you know what you're getting. I don't know what they
put in those cigarettes."