The health effects of smoking are the circumstances, mechanisms, and factors of tobacco consumption on human health. Epidemiological research has been focused primarily on cigarette tobacco smoking, which has been studied more extensively than any other form of consumption.
Tobacco is the single greatest cause of preventable death globally. Tobacco use leads most commonly to diseases affecting the heart, liver and lungs, with smoking being a major risk factor for heart attacks, strokes, chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), and cancer (particularly lung cancer, cancers of the larynx and mouth, and pancreatic cancer). It also causes peripheral vascular disease and hypertension. The effects depend on the number of years that a person smokes and on how much the person smokes. Starting smoking earlier in life and smoking cigarettes higher in tar increases the risk of these diseases. Also, environmental tobacco smoke, or secondhand smoke, has been shown to cause adverse health effects in people of all ages. Cigarettes sold in underdeveloped countries tend to have higher tar content, and are less likely to be filtered, potentially increasing vulnerability to tobacco-related disease in these regions.
Nicotine gum is a type of chewing gum that delivers nicotine to the body. It is used as an aid in nicotine replacement therapy (NRT), a process for smoking cessation and quitting smokeless tobacco. The nicotine is delivered to the bloodstream via absorption by the tissues of the mouth.
It is currently available over-the-counter in Europe, the US and elsewhere. The pieces are usually available in individual foil packages and come in various flavors. Nicotine content is usually either 2 or 4 mg of nicotine, roughly the nicotine content of 1 or 2 cigarettes, with the appropriate content and dosage depending on the smoking habits of the user. Popular brands include Nicoderm/Nicorette, Nicogum and Nicotinell.