Tobacco is the leading cause of preventable deaths in Ireland, and long-term smokers have a life expectancy that's 10 years less than a non-smoker. Smoking is also the top risk factor for lung cancer, heart disease, stroke, and chronic obstructive pulmonary disease (COPD, chronic bronchitis or emphysema).Quitting smoking will also help your general fitness, the appearance of your skin and teeth and could help your fertility.