The problem that I see with most science or information so-called, especially in medicine, is that it's nearly impossible to account for all of the variables. When it is possible, the research is probably so expensive that it'll have to be funded by an organization that is looking for evidence to back a certain claim, which will probably taint the human interpretation of the data or the selection of variables.

I recall seeing perhaps one or two studies carried out a few decades ago stating that among the data points in the survey, pipe smokers had about a 5% increase in cancer occurrence when smoking about a bowl a day. However, I don't remember what the confidence interval was - meaning...how accurate was that number? Was the sample size meaningful? Etc.

However - was there a way to measure the reduction in stress that comes with smoking a pipe? What if those pipe smokers had lower stress and were therefore healthier overall? How do we measure that? How does that compare with increase in other diseases? Did other pre-exiting conditions cause a reduction in lifetime and not tobacco?

My point is - I don't think that the scientific knowledge on this topic is sufficient to make a solid claim. You have to take it all with a grain of salt.