Hello! I'm Andy, i'm new here on STM Forum, I ask you sorry for my bad english, i'll try to make it better day by day.
I'm starting a campaign on FB (CPA offer), the product is a "stop smoking" stuff and i think it's quite a dangerous argoument so i tried to do my best:
Hey @andyqueue, i'm promoting an affiliate product is this niche too, and i suggest you to set up a broad targeting because there aren't specific interests for targeting a smoker. Anyone could be a smoker, even a sporty person. Do create 10 adset for your campaign: 5 adsets targeting women (every adset should have 1 age range, for ex. 18-24, 25-44 etc.) and 5 adsets targeting men (same thing for the age range). Hope to be helpful 
Thank you @alessandropalazzi, it was my first idea... Your name seems to be italian, are you? (like me!!) is
I have read the lower income people smoke most in general. Select low educated people for a test at least!
Vapers/e-smokers are quite a growing community too by the way. There must be a way to put them in your interest somehow. But they might not be very open to those kind of products. Not sure. Your angle must be subtle without annoying them, it could be touchy for them since they “found” a way to quite actual smoking now.