It was in the 1960s that warnings were put on labels in the U.S. for cigarettes and health consequences. In 1966 the label read: "Caution: cigarette smoking may be hazardous to your health" in the U.S. The health risk were known in the 1950s but lobbying in the U.S. prevented much stronger action especially with respects to the labels even though some states tried and failed to make the labels stronger.
In 1964 the U.S. Surgeon General had this statement:
- A cause of lung cancer and laryngeal cancer in men
- A probable cause of lung cancer in women
- The most important cause of chronic bronchitis
The Tobacco Industry held immense clout for a very long time. The health risks were known though and the packages were labeled though less labeling in the U.S. compared to other countries but of course if you have a label saying one thing and the Tobacco Industry saying another thing and you're bombarded with the image of smoking you may be less inclined to think it really is adverse to your health. Now in terms of addictiveness I haven't looked into that if that was very well presented in the past.
Now other countries did have stronger more specific labels while the U.S. continued to have the original one vastly due to the Tobacco Industry's stronghold.
But to your point I don't think the general public paid much attention to it until the mid-to-late '80s with it ramping up more and more over time especially as the Tobacco Industry began losing power. The warning labels have become more specific overtime as well.
All that being said I don't know the history in Canada.