For cigarettes, if you dial back what you consider moderation to say, maybe a cig or two socially every couple weeks, that would not likely be the thing that killed you. there are smokers like that, they just have a couple at a party, not very often. It's not something most people would do but there are some out there that do.
I'd say most cigar or pipe smokers I know are like this.
I think it's less common with cigarettes now for various reasons. The social stigma, the fact that they are much more convenient, and that they deliver their nicotine "hit" much faster, I would imagine makes them more addictive.
A reduced risk for Parkinson's disease (PD) among cigarette smokers has been observed consistently during the past 30 years. Recent evidence suggests that caffeine may also be protective. Findings are presented regarding associations of PD with smoking, caffeine intake, and alcohol consumption from a case-control study conducted in western Washington State in 1992–2000.
Being a cigarette smoker was observed to reduce risk of PD. This study does not tell us if it's the smoking itself that's causing this, or some other trait of cigarette smokers because the studies weren't randomized.
