Moonbear said:
I don't know about a genetic component (not disputing, just never looked into it to confirm or refute that). But, anecdotally, the only non-smokers I've known of to get emphysema where it couldn't be attributed to second-hand smoke exposure were indeed those working in dusty environments (feed mills where they're grinding grains and everything is coated in a fine dust...a lot of the people working in those don't bother wearing dust masks or respirators, and really should).
Curious covered the genetic thing.
AFAIK Black lung, Brown lung and Silicosis are all variant names for emphysema.
Your observation would have a consistent mechanism.
I think Smog is also a problem.
Don't those grain silos have a nasty tendency to explode?
When some people say their job is killing them...
The latest and greatest study designed to show a link between second hand smoke and health risks.
No Effect.
Some people are very upset by this and want the study withdrawn.
I recall the following from a journal article on the risks of obesity.
"Being 10lbs overweight carries the health risk equivalent of smoking a pack of cigarettes a day. "
And
"The effects of overweight are non linier so being 20lbs over is much worse then 10lbs. "
To me, this sounds a little extreme.
OTOH, there are all those restricted diet lifespan extension studies showing huge effects.