Prevention is worth a pound of cure. That’s one reason that long-term health studies can be so immensely valuable. For example, it was the decades-long gathering and interpretation of large amounts of medical records, crossed with lifestyle data, that proved conclusively the cause-and-effect relationship of tobacco use with cancer, heart disease and a long list of other maladies.

Such studies are just as valuable when they reveal a negative correlation. What a relief that studies of cell phone use and brain cancer revealed no link between the two. Or that vaccinations had no effect on rates of autism.

So it was good news when results from a long-term study were published recently, concluding “neither cumulative lifetime nor recent use of marijuana is associated with the incidence of CVD in middle age.”

The study’s credibility is strengthened by its methodology, where the health of over 5,000 adults was followed for more than 25 years, during which 84% of sample reported a history of cannabis use.

What this could mean for patients who might benefit from the medical use of cannabis is that some healthcare practitioners may reconsider their previously-held negative opinions of the drug, and be more amenable to accepting it as a viable medicine, one that they can now recommend with increased confidence they will not compromise their oft-stated primary professional responsibility, which is to “do no harm.”