marijuana does not cause lung cancer

Marijuana smoking does not increase a person's risk of developing lung cancer, according to the findings of a new study at the University of California Los Angeles that surprised even the researchers.
They had expected to find that a history of heavy marijuana use, like cigarette smoking, would increase the risk of cancer.
Instead, the study, which compared the lifestyles of 611 Los Angeles County lung cancer patients and 601 patients with head and neck cancers with those of 1,040 people without cancer, found no elevated cancer risk for even the heaviest pot smokers. It did find a 20-fold increased risk of lung cancer in people who smoked two or more packs of cigarettes a day.
The study results were presented in San Diego Tuesday at a meeting of the American Thoracic Society.

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