Smoking and Cancer: A Case Study for Epidemiology
This post launches the start of a series of posts that will eventially form a full article on the history of smoking and cancer. It will cover how the link was eventually found, and what it did for the science of epidemiology (or spread of disease in a population).
According to wikipedia
The health effects of tobacco have been significant for the development of the science of epidemiology. As the mechanism of carcinogenicity is radiomimetic or radiological, the effects are stochastic. Definite statements may be made only on probabilities of contracting disease. When considered philosophically and theoretically, it is in principle impossible to prove a direct causative link between exposure to a radiomimetic poison such as tobacco smoke and the cancer that follows. Tobacco companies have capitalized on this philosophical objection and exploited the doubts of clinicians, who consider only individual cases, on the causal link in the stochastic expression of the toxicity as actual disease.
Basically, it is very difficult to prove any causation between environment, lifestyle, and human health. The reason of course is that these are highly dynamic systems, victims of chance. This is why so many health studies have to be stated with vague qualifiers like "may cause" or "might increase your chance", because the truth is there is no universal condition for everyone.
What is so interesting about smoking is that the risk factors have likely been overstated, but the marketing and general negative publicity has turned it into a public health horror. The question here is how the phenomenon with cigarettes got to the point where people can openly talk and help others beat the addiction, it is a great thing, and should likely happen more with sugar and obesity.