Researchers found a high incidence of cardiovascular death among marijuana users but the study has limits. Authors said more research is needed.

…It also assumed that those who said they had used marijuana in 2005 continued to do so, and it assumed that users largely smoked their pot and didn’t consume it in other ways, such as by eating marijuana-laced brownies.

Those caveats limit the study’s validity, said Dr. Vinay Prasad, associate professor of medicine at Oregon Health & Science University and an expert on the design and results of medical studies.

“It does not prove that if you choose to use marijuana you are more likely to die of cardiovascular disease,” Prasad said in an email. “I think the major limit of the study is that there may be unobserved differences between the people who used and admitted to using marijuana during the years of this study, and cardiovascular outcomes that the researchers did not adjust for.  In fact, that is likely.”

Study linking cardiovascular death and marijuana far from conclusive | OregonLive.com

hmmm