Maybe you should read the reply I posted above your reply.
Only in random controlled trials , you can prove something has
caused cancer. All drugs have to go through randomised controlled
trials to make sure they are truly effective.
Smoking has no human random controlled trials because of the ethics
involved. The evidence they taken are mostly from cohort studies
which in epidemiological terms will only prove an association
NOT a causal relationship . From there, the
conclusion is open to interpretation and some studies are flawed.
There are effect modifiers in them such as genetic predisposition
(i.e. BrCa mutations which put some women at higher risk of breast
cancer) , dose-response, lifestyle choices and even environmental
factors.
They permitted smoking in the past in poorly ventilated buildings .
It's like having a fire and you breathing in the smoke from the
fire constantly - of course the lungs of second hand and first hand
smokers go kaput. It's similar to eating - you eat too much - you
become fat - you have clogged arteries and heart problems. Even too
much pure oxygen is toxic for the brain.
However in an open space , it is a different story - similar to
smelling BBQ smoke while you are BBQing food. No doubt smoking
lacks the aromatic smells of a food cooking but most smokers are
not always smoking constantly . Open space = open ventilation .That
is a reason why kitchens have to be well ventilated as well , just
in case the food burnts and the smoke from burning food is more
acrid than the cigarette I smoke.
As for environmental smoking pollution, well excuse me if you sniff
at the car's exhaust only without ventilation , you die from carbon
monoxide poisoning. Cars emit the more than a smoker does. All the
comparisons to smoking are based on predictive mathematical
modelling which means shat to me - it may be happen but it cannot
be proven it actually happens .... they cannot
actually estimate how the force of an individual's inhalation at a
go or the temperature of the smoke going in - hence dose response
issues. No freaking experimental box on a substitute for a lung is
going to be like my lungs or anyone elses.
