THE GOOD NEWS AND BAD NEWS ABOUT POT

Two major studies on the health effects of marijuana were published
this week, but they blew in opposite directions.

One study found that cannabis could be an effective means of easing
nerve pain in patients infected with the virus that causes AIDS.
"This placebo-controlled clinical trial showed that people with HIV
who smoked cannabis had substantially greater pain reduction than
those who did not smoke cannabis," said Donald Abrams, who led the
research team at the University of California, San Francisco.

Dr. Abrams, whose study was published in the journal Neurology, noted
that nerve pain can be extremely debilitating and difficult to treat.

Many patients don't get relief from conventional medications.

"These results provide evidence there is a measure of medical benefit
to smoking cannabis for these patients," he added.

The other study, however, pointed to a dark side of marijuana use,
suggesting it might harm the lungs.

"There does seem to be an association between long-term marijuana
smoking and respiratory complaints such as increased cough, phlegm
and wheeze -- all symptoms associated with obstructive lung disease,"
said the lead researcher, Jeanette Tetrault at Yale School of
Medicine in Connecticut.

This second study, published in the Annals of Internal Medicine, was
based on a review of 34 previous marijuana trials.

But Dr. Tetrault readily acknowledged there were methodological
problems with a lot of these earlier trials.

As a result, her research team failed to show conclusively that
prolonged marijuana use can lead to serious lung problems such as
emphysema. "Our bottom line is that we can't say for sure."

Even so, other scientists welcomed the release of both studies,
despite their conflicting and somewhat inconclusive findings.

"These studies need to be done," said Dr. Mark Ware, who has been
conducting similar research at McGill University in Montreal. He
noted numerous drug companies are working on ways to harness the
medicinal effects of cannabis in pill form so it doesn't need to be smoked.

"But it's important that we keep evaluating the long-term risks and
benefits of the smoke because people will probably continue to do it
this way. And we need to know what to tell them," he said.

Cesarean Risks

The too-posh-to-push crowd should take heed of new research on the
potential risk of cesarean sections.

The study, published in the Canadian Medical Association Journal,
found that planned C-sections are three times more risky than vaginal births.

Those risks include an increased chance of infections, blood clots
and other complications from the surgery.

In recent years, however, a growing number of Canadian women have
been opting for C-sections. The rate of C-sections soared to 25.6 per
cent of all births in 2003, from 5.2 per cent in 1969.

Some of these operations are medically necessary, but others appear
to be a matter of choice.

Some women might seek a C-section because it appears to be easier and
more convenient than a vaginal birth, noted the lead researcher, Dr.
Robert Liston of the University of British Columbia in Vancouver.
"And a lot of people are frightened of labour."

However, he said, surgery also carries risk. The study findings
indicate that the rate of severe complications among those having a
planned C-section was 27.3 for every 1,000 deliveries, compared with
nine for every 1,000 deliveries among women giving birth vaginally.

Still, Dr. Liston was quick to point out that childbirth is
relatively safe in Canada, regardless of the method of delivery.

"The chances are that everything will be fine, but you are increasing
your risk of having one of these nasty events by undergoing a planned
C-section," he said. "Going the natural route is preferable."

Lung Cancer and Women

Not all cases of lung cancer are caused by a lifetime of smoking.

An estimated 10 to 15 per cent of people stricken with the
potentially deadly disease have never smoked a cigarette, cigar or
pipe. And a new study suggests that non-smoking women may be more
prone to lung cancer than non-smoking men.

Using statistics from both the United States and Sweden, the research
team found that about 8 per cent of lung-cancer cases in males and
close to 20 per cent of cases in females are among "never-smokers."

So, why does lung cancer seem to pick on women? "We just don't know,"
said Heather Wakelee, the lead researcher at Stanford University
school of medicine in California.

In their paper, published in the Journal of Clinical Oncology, the
researchers point to a variety of factors that might trigger cancer
in abstainers.

They include environmental and occupational exposures to certain
substances such as asbestos and chromium.

Radon, seeping into homes from underground sources, has also been
linked to lung cancer. And arsenic in drinking water has been implicated.

Yet none of these factors seem to explain the higher rates found in
women. The answer to the riddle might be found in hormonal levels or
other physical differences in women and men.

But it is also possible that some cases are still tied to smoking --
at least indirectly.

Secondhand smoke, for example, could explain part of the gender
difference, speculated Ellen Chang, a co-author of the study. Because
more men smoke than women, she said, women may be more likely to be
exposed to secondhand smoke.