The risk of lung cancer increases with the number of cigarettes smoked over time. Doctors refer to this in terms of pack-years of smoking history (the number of packs of cigarettes smoked per day multiplied by the number of years of smoking).
It's good to know that people that stop smoking before their 35 year of life, get their risk decreased by 90% in following years.

Well I heard on several occasions that if you smoke 20 years or more than your risk goes up considerably. I also heard what you said that if you quit before age 35 your risk is alot better.

Also I am only 32 years old and quit...