Lung cancer was virtually non-existent in 1900.
http://www.lungcancersurgery.org/lun...er_history.htm
As Sam Donaldson once famously opined on network television in the late 1980's, signalling a harder shift in attitudes, paraphrased, "Its none of my business if you smoke, right up until that smoke reaches my nose. Then it IS my business."
Its not necessarily tobacco itself but rather the carcinogens that are added to give it appeal and flavour that make it truly dangerous through time to the smoker and everyone around.
Cowperson