[orthodoc]

The epidemiological evidence is in, and it's clear: smoking does indeed cause lung cancer. A (perhaps) interesting anecdote: when I was in medical school in Toronto, one of my professors told a story about being called to see a patient in the 1920s who had lung cancer. All of the house staff and students were called to see this patient, because he had an incredibly rare disease that they probably wouldn't ever see again in their lives.

That would have been a logical assumption given the disease prevalence at the time, but not so much given the relatively recent change in human habits.

All of which is to say that, while many changes have occurred in our lives, diets, habits, and styles of living, it is possible to make meaningful conclusions from good epidemiological data. The data connecting smoking and lung cancer were always epidemiological. All correct. We can make meaningful conclusions and take steps to protect the health of others in the future.

It's not as hopeless as some feel, when confronted with the latest epidemiological study. There are limitations, but there are also useful conclusions to be made.