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Study: smoking pot raises level of harmful chemicals in body but smoking tobacco is more harmful

A worker wearing protective gear trimmed a medical cannabis plant at a facility in Colombia last month.Ivan Valencia/Bloomberg

Marijuana smoking can raise levels of potentially harmful chemicals in someone’s body, but to a lesser extent than tobacco, according to a new study from researchers at the Dana-Farber Cancer Institute and the CDC.

The study, published online by EClinicalMedicine on Monday, involved 245 HIV-positive and HIV-negative participants in three studies of HIV infection in the United States, according a statement from Dana-Farber.

Researchers found that participants who only smoked pot had higher blood and urine levels of several smoke-related chemicals such as naphthalene, acrylamide, and acrylonitrile metabolites than non-smokers, according to the statement.

But the concentrations of such substances were lower in marijuana-only smokers than in tobacco puffers, the statement said.


In addition, the statement said, the study found that acrolein metabolites — generated by the breaking down of acrolein — were elevated in tobacco smokers but not in pot users.

“Marijuana use is on the rise in the United States with a growing number of states legalizing it for medical and nonmedical purposes — including five additional states in the 2020 election,” study senior author Dr. Dana Gabuzda said in the statement. “The increase has renewed concerns about the potential health effects of marijuana smoke, which is known to contain some of the same toxic combustion products found in tobacco smoke.”

The study, the statement said, found that exposure to acrolein, a chemical produced by the combustion of multiple materials, increases with tobacco smoking but not marijuana smoking and contributes to cardiovascular disease in tobacco smokers.

“Our findings suggest that high acrolein levels may be used to identify patients with increased cardiovascular risk,” Gabuzda said. “And that reducing acrolein exposure from tobacco smoking and other sources could be a strategy for reducing risk.”

Travis Andersen can be reached at travis.andersen@globe.com. Follow him on Twitter @TAGlobe.