tobacco(redirected from Nicotianas)
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Cigarette smoking is the leading preventable cause of disease and death in the U.S., being responsible for approximately 440,000 deaths (20% of all deaths) each year, and approximately $157 billion in health-related economic losses. Smoking two packages of cigarettes a day reduces life span by 8.3 years. Smoking tobacco in any form (cigarettes, cigars, pipe) is a strong independent risk factor for atherosclerosis, acute myocardial infarction, unstable angina, stroke, and sudden death. Tobacco is responsible for 81,000 deaths annually due to ischemic heart disease (including 45% of all deaths due to coronary artery disease in men under 65) and more than 50% of all strokes in both sexes before age 65. Smoking lowers HDL cholesterol and raises LDL and VLDL cholesterol, and increases the risk of intermittent claudication and aortic aneurysm. It may cause as much as a 30-fold increase in the risk of thromboembolic disease in women taking oral contraceptives. Smoking is responsible for 124,000 deaths each year due to lung cancer, and markedly increases the risk of other cancers, particularly those of the oral cavity, larynx, esophagus, kidney, bladder, uterine cervix, and pancreas. Cigarette smoking is the principal cause of chronic bronchitis and pulmonary emphysema. Involuntary or passive smoking (inhalation by nonsmokers of second-hand or sidestream smoke) causes 53,000 deaths annually, 37,000 of them due to coronary artery disease. Maternal smoking during pregnancy is associated with increased risk of miscarriage, stillbirth, and low birth weight. Children of smokers are at increased risk of sudden infant death syndrome, meningococcal meningitis, and dental caries. Use of smokeless tobacco (chewing tobacco or snuff applied to the buccal mucosa) greatly increases the risk of cancer and premalignant lesions of the oral cavity. Nicotine use is powerfully addictive, leading to habituation, tolerance, and dependency. In the U.S., 90% of smokers become habituated to tobacco before age 21 and 3,000 children begin smoking each day. The likelihood of becoming and remaining a smoker increases in inverse proportion to the number of years of education completed. Quitting smoking decreases the risk of death from all causes by 30%. Effective strategies for smoking cessation include behavior modification therapy, nicotine replacement (gum, skin patches, inhaler, nasal spray), hypnosis, and drug therapy (bupropion, clonidine, nortriptyline), but the relapse rate 3 months after smoking cessation is 60%.