Just to provide a bit of background info…
It was suspected that tobacco use was harmful to one’s health relatively soon after it was introduced to Europe. James I of England wrote a treatise called “A Counterblaste to Tobacco” in 1604. I’ve been unable to find the whole treatise online, but I’ve found several sites that quote it. You can find selections here and here.
Seems that His Majesty had little use for this plant, but I have no idea how seriously other people took this warning, nor how prevalent the sentiment was in Jacobian England.
There seems to have been an awareness that tobacco was harmful to one’s health much earlier than the Surgeon General’s campaign mentioned earlier. “Coffin nail” was a slang term for cigarette that dates at least to the early Twentieth century, though I haven’t been able to find a cite that mentions an approximate origin for the term. I have to get to class, so I don’t have the time for a more thorough search right now. I’m sure there are other dopers who can make up for my shortcomings.
So in short, it seems that people were aware of the possibly harmful effects of tobacco use relatively soon after its introduction to Europe, and it seems to precede both the modern anti-tobacco blitz and today’s heavily processed tobacco products. Not being a smoker myself, though, I can’t speculate on why this practice became so popular.