Many more die early due to heart attacks. People react differently to all substances for a variety of reasons, including genetic and biological make-up. Since cigarette smoke contains so many thousands of chemicals, it's no wonder that every smoker doesn't contract the same disease. That is why many life insurance companies are now reducing life insurance policy premiums for non-smokers. Among smokers, the death rates from many causes increase with the number of cigarettes smoked per day, the number of years the smokers has smoked, and the earlier the age at which smoking was started.
Lung cancer is extremely rare in non-smokers.
A small number of lung cancers may be due to exposure to certain chemicals at work, exposure to radon gas and exposure to second-hand tobacco smoke. Perhaps, to a small degree. In industrial areas or cities haevily polluted with smog, lung cancer rates are slightly higher than in rural areas. But in both places, the lung cancer rates are always very much higher among smokers than non-smokers because pollutants in the air are more diluted than those in cigarette smoke. In certain industries where there are high concentrations of radio-active dust or other carcinogens, the lung cancer rate is much greater than in the general population.