Lung cancer is the most common form of cancer caused by smoking. The earlier you quit, the lower your risk of dying form lung cancer. For example, quitting at 50-years-old more than halves your risk over 5 years compared to continued smoking. Cigarette smoke contains many chemicals that interfere with the body’s method of filtering air and clearning out the lungs.
After quitting, your risk of cancer of the stomach, pancreas and oesophagus goes down compared to a continuing smoker, and continues to decrease the longer you stay stopped. Smoking causes peptic ulcer disease in people who are also infected with H. pylori, a common bacterial infection. It increases the risk of developing Crohn’s disease, a chronic inflammatory bowel condition. Smoking has a number of damaging effects on your stomach and gut (such as increasing acidity and reflux) which stop shortly after you quit smoking.