smoking is also responsible for 85% of all lung cancer deaths and 30% of all cancer deaths. An estimated 21% of all cases of coronary heart disease can be attributed to cigarette smoking. It is a major risk factor for diseases of the heart and blood vessels; for chronic bronchitis and emphysema; for cancers of the lung, larynx, pharynx, oral cavity, esophagus, pancreas, and bladder; and for other problems such as respiratory infections and stomach ulcers.