Health risks

The United States's       Centers for Disease Control and Prevention describes tobacco use as "the single most important preventable risk to human health in developed countries and an important cause of premature death worldwide".

The main health risks in tobacco smoking pertain to diseases of the cardiovascular system, in particular smoking being a major risk factor for a     myocardial infarction (heart attack), diseases of the       respiratory tract such as Chronic Obstructive Pulmonary Disease (COPD) and emphysema, and cancer, particularly lung cancer and        cancers of the larynx and tongue. Previous to World War I, lung cancer was considered to be a rare disease, which most physicians would never see during their career. With the postwar rise in popularity of cigarette smoking, however, came a virtual epidemic of lung cancer.

A person's increased risk of contracting disease is directly proportional to the length of time that a person continues to smoke as well as the amount smoked. However, if someone stops smoking, then these chances steadily although gradually decrease as the damage to their body is repaired.

Diseases linked to smoking tobacco cigarettes include:
 * lung cancer and other cancers
 * stroke
 * peripheral vascular disease
 * birth defects of pregnant smokers' offspring
 * Buerger's disease (thromboangiitis obliterans)
 * impotence
 * chronic obstructive pulmonary disease, emphysema and chronic bronchitis in particular

Cigar and pipe smokers tend to inhale less smoke than cigarette smokers, so their risk of lung cancer is lower but is still several times higher than the risk for nonsmokers. Pipe and cigar smokers are also at risk for cancers of the oral cavity, larynx (voice box), or esophagus. Cancer of the mouth and jaw is also a risk for people who chew tobacco rather than smoke it.