[classicmotto]

Seems misleading.

"Marijuana users excluded and added to Marijuana smokers group".

Would have been fruitful if there were 4 groups, Marijuana only, Mixed, Tobacco only, and Non-Smokers.

The introduction seems kinda biased from the start:

"Marijuana is the most widely used illicit psychoactive substance in the world (1) and the second-most commonly smoked substance after tobacco..."

"...Its use has increased in Canada since the legalization of Medical...".

does not compute.