Large Study Finds No Link between Marijuana and Lung Cancer

Scientific American ^ | May 24, 2006 | NA

[neverdem]

The smoke from burning marijuana leaves contains several known carcinogens and the tar it creates contains 50 percent more of some of the chemicals linked to lung cancer than tobacco smoke. A marijuana cigarette also deposits four times as much of that tar as an equivalent tobacco one. Scientists were therefore surprised to learn that a study of more than 2,000 people found no increase in the risk of developing lung cancer for marijuana smokers.

"We expected that we would find that a history of heavy marijuana use--more than 500 to 1,000 uses--would increase the risk of cancer from several years to decades after exposure to marijuana," explains physician Donald Tashkin of the University of California, Los Angeles, and lead researcher on the project. But looking at residents of Los Angeles County, the scientists found that even those who smoked more than 20,000 joints in their life did not have an increased risk of lung cancer.

The researchers interviewed 611 lung cancer patients and 1,040 healthy controls as well as 601 patients with cancer in the head or neck region under the age of 60 to create the statistical analysis. They found that 80 percent of those with lung cancer and 70 percent of those with other cancers had smoked tobacco while only roughly half of both groups had smoked marijuana. The more tobacco a person smoked, the greater the risk of developing cancer, as other studies have shown.

But after controlling for tobacco, alcohol and other drug use as well as matching patients and controls by age, gender and neighborhood, marijuana did not seem to have an effect, despite its unhealthy aspects. "Marijuana is packed more loosely than tobacco, so there's less filtration through the rod of the cigarette, so more particles will be inhaled," Tashkin says. "And marijuana smokers typically smoke differently than tobacco smokers; they hold their breath about four times longer allowing more time for extra fine particles to deposit in the lungs."

The study does not reveal how marijuana avoids causing cancer. Tashkin speculates that perhaps the THC chemical in marijuana smoke prompts aging cells to die before becoming cancerous. Tashkin and his colleagues presented the findings yesterday at a meeting of the American Thoracic Society in San Diego.

[neverdem]

This undermines the argument that smoked medical marijuana is too toxic and dangerous as a method of administration.

[freepatriot32]

ping

[kinoxi]

if they free the pot smokers they'd have enough room for the illegals

[Pro-Bush]

420

[gleeaikin]

Another good reason to stop jailing, and release personal users and minor distributors of pot. We need more prison space for potentially dangerous illegal aliens (especially non Latin Americans) and gang members.

[drlevy88]

Chain smoking, as with tobacco, would be quite impossible with pot. The smoker would be too zonked to continue.

[freepatriot32]

might be of interest to you guys.I wonder if you give this report to a second hand smoke nazi would thier heads explode :-)

[WhistlingPastTheGraveyard]

Tashkin speculates that perhaps the THC chemical in marijuana smoke prompts aging cells to die before becoming cancerous.

A study of the cancer rates among cigarette smokers who also smoke marijuana might be interesting.

[zarf]

Legalize pot and ban malt liquor = empty jails

[djf]

The whole smoking-cancer thing is suspect. For instance, the Japanese, who smoke far more than Americans on average, have a much lower incidence of lung cancer.

Personally, once again, I'm inclined to think this is nutrition/dietary deficiency related. Possibly Vit D.

[weegee]

That sounds racist when you consider that gangs and border crossers make their money in the drug trade. If we legalzie the drugs, they commit no crimss to arrest them on.

Or do we keep it illegal for "large" quantity? Would they still war over turf? How does that help things? Or would the criminals just fill the void with another illegal substance?

[1955Ford]

I don't believe it. The study seems flawed. The obvious way to answer the question is to compare the incidence of lung cancer in marijuana smokers and non smokers. Instead the study looked at the numbers of pot smokers and non smokers in a population of cancer patients. what does that show?

[DakotaRed]

As if this is a legitimate study to be taken seriously? From the intitial report issued yesterday;

"The study was confined to people under age 60 since baby boomers were the most likely age group to have long-term exposure to marijuana"

Hmmm. Only 611 from how many millions of users? And, only under age 60? When I tried it back in the day, the majority using it were at least a few years older than me and I'm approaching 58 now. Could there be a reason they neglected to study those exposed longer?

"The results should not be taken as a blank check to smoke pot, which has been associated with problems like cognitive impairment and chronic bronchitis, said Dr. John Hansen-Flaschen, chief of pulmonary and critical care at the University of Pennsylvania Health System in Philadelphia."

Seems it isn't as harmless as potheads wish to think.

"Hansen-Flaschen also cautioned a cancer-marijuana link could emerge as baby boomers age and there may be smaller population groups, based on genetics or other factors, still at risk for marijuana-related cancers."

Oh? Are they worried about when aging Baby Boomers pass 60? They couldn't study them now?

http://famulus.msnbc.com/famulusgen/reuters05-23-183641.asp?t=renew&vts=52320061923

[BJungNan]

Now that's a relief, err, I mean, that would be a relief to some who may have tried it once or maybe three times.

[aquila48]

"The researchers interviewed 611 lung cancer patients and 1,040 healthy controls as well as 601 patients with cancer in the head or neck region under the age of 60 to create the statistical analysis. They found that 80 percent of those with lung cancer and 70 percent of those with other cancers had smoked tobacco while only roughly half of both groups had smoked marijuana."

Apparently the researchers doing this study smoked dope while doing it.

The paragraph above is missing an important datum. What percentage of the control group smoked cigarettes vs. dope. I would venture to guess that there were a lot more that had smoked tobacco than dope, probably more than 8 to 5!

[TigersEye]

The whole smoking-cancer thing is suspect. For instance, the Japanese, who smoke far more than Americans on average, have a much lower incidence of lung cancer.

The same is true in France where they smoke stronger tobacco and mostly unfiltered cigarettes.

[traviskicks]

Libertarian ping! To be added or removed from my ping list freepmail me or post a message here.

[TigersEye]

Instead the study looked at the numbers of pot smokers and non smokers in a population of cancer patients. what does that show?

That people get cancer.

[traviskicks]

There's been a similar idea to that one regarding radiation (ie radiation is bad for you, yet because it kills aging/weaker cells, you sometimes get good effects). I dunno, I don't know much about it, but can't say i really buy into it.

[tallhappy]

Rather ludicrous interpreation and speculation.

70% smoked tobacco and 50% dope. But the dope is not correlated?

The entire article is very misleading.

If true it actually says more about the cause of tobacco promoting cancer in that the cause is obviously not known.

If this bears out it is a ajor finding in that it would indicate that they are wrong about what in tobacco causes cancer and the differences between dope smoke and tobacco can be used to perhaps find out what the actual causative agent is.

For example, there could be asbestos in tobacco but not dope.