New Research Links Marijuana Use With Cancer Risk

June 17, 2009 6:55 a.m. EST

London, England (AHN) - Swedish researchers say cannabis from marijuana smoke damages DNA in ways that could increase the risk of cancer development in humans.

The scientists said they found that cannabis smoke does damage DNA in laboratory conditions.

The toxicity of tobacco smoke has been proven by many studies over the years. It contains 4,000 chemicals and 60 of them are considered carcinogens - meaning they cause cancer. The toxicity of cannabis smoke has been studied far less, and researchers have had a harder time determining if smoking pot causes cancer because it is often mixed with tobacco use.

Raj Singh, a researcher from the Cancer Biomarkers and Prevention Group of the Department of Cancer Studies and Molecular Medicine and Karolinska Institute in Sweden, said because of cannabis' lower combustibility, it contains 50 percent more carcinogenic polycyclic aromatic hydrocarbons, including naphthalene, benzanthracene and benzopyrene than tobacco smoke.

Singh and his colleagues say their latest research provides more evidence that smoking pot "may be detrimental to human health with the possibility to initiate cancer development."

The study is published by the University of Leicester in the journal Chemical Research in Toxicity.