New research suggests that smoking both marijuana and cigarettes almost triples the risk of developing chronic obstructive pulmonary disease (COPD). However, smoking marijuana alone was not linked to increased risk, Forbes reported April 12.
Researchers from the University of British Columbia looked at data from the Burden of Obstructive Lung Disease Initiative, which documents COPD prevalence among people over age 40. Those who smoked both marijuana and cigarettes were 2.5 times more likely than nonsmokers to develop respiratory disease and almost three times as likely to have COPD, the study found.
Marijuana may act as a sort of “primer” in the airways, possibly augmenting the negative effects of tobacco on respiratory health, said lead researcher Wan Tan. “Smoking marijuana and cigarettes — even small amounts — is very harmful for your lungs, ” Tan said.
American Lung Association scientific consultant Norman H. Edelman speculated that individuals who smoke both marijuana and tobacco may inhale both more deeply than smokers of tobacco only, increasing the risk of lung damage.
The findings were published April 14, 2009 in Canadian Medical Association Journal.