Nicotine Dependence

Risk factors

Although many associate smoking first and foremost with lung cancer and lung diseases, smoking harms every organ in the body. Cigarette smoking has been linked to about 90% of all lung cancer cases, the number-one terminal cancer in both men and women. Smoking is thought to account for about one-third of all cancer deaths.The overall rate of death from cancer is twice as high for smokers compared to nonsmokers, with heavy smokers having a rate four times greater than nonsmokers. Smoking is also associated with cancers of the mouth, pharynx, larynx, esophagus, stomach, pancreas, cervix, kidney, ureter, and bladder.

Smoking also causes lung diseases such as chronic bronchitis and emphysema, and has been found to exacerbate asthma symptoms in adults and children. More than 90% of all deaths from chronic obstructive pulmonary diseases are attributable to cigarette smoking. It has also been well documented that smoking substantially increases the risk of heart disease, including stroke, heart attack, vascular disease, and aneurysms. It is estimated that smoking accounts for approximately 21% of deaths from coronary heart disease each year.

Additionally, secondary smoke increases the risk for many diseases. It is estimated to cause approximately 3,000 lung cancer deaths per year among nonsmokers and contributes to more than 35,000 deaths related to cardiovascular disease. Exposure to tobacco smoke in the home is also a risk factor for starting to smoke and increased severity of childhood asthma and has been associated with sudden infant death syndrome.

Prevention and treatment

The best and most simple prevention is never to start smoking. For people who have already started to smoke, the best prevention is to quit.

Smoking cessation can have immediate health benefits. For example, within 24 hours of quitting, blood pressure and chances of heart attack decrease. Long-term benefits of smoking cessation include decreased risk of stroke, lung and other cancers, and coronary heart disease. A 35-year-old man who quits smoking will, on average, increase his life expectancy by 5.1 years.

Although some smokers can quit without help, many individuals need assistance in quitting. The following treatments are availableto help people quit:

• Nicotine replacement therapies, such as nicotine gum and the transdermal nicotine patch are used (often with behavioral support) to relieve withdrawal symptoms and thereby reduce the discomfort associated with quitting. These treatments provide users with lower overall nicotine levels than they receive with tobacco, hence they do not produce the pleasurable effects of smoking, nor do they contain the carcinogens and gases associated with tobacco smoke.
• Non-nicotine medications, such as the antidepressant bupropion has been shown to help people quit smoking. A more recently approved medication is varenicline , which acts at the sites in the brain affected by nicotine and may help people quit by easing withdrawal symptoms and blocking the effects of nicotine if people resume smoking.Several other non-nicotine medications are being investigated for the treatment of tobacco addiction.
• Behavioral support has been shown to enhance the effectiveness of other treatments and improve long-term outcomes. It includes a variety of methods to assist smokers in quitting, ranging from self-help materials to individual cognitive-behavioral therapy.

Scientists are also investigating a nicotine vaccine, which is designed to stimulate the production of antibodies that would block access of nicotine to the brain and prevent nicotine&rquote;s reinforcing effects.

More information

You can find out more information about nicotine dependence and smoking by talking to your doctor and visiting these Web sites:

• Centers for Disease Control and Prevention on Smoking and Nicotine Dependence
• Mayo Clinic article on Nicotine Dependence
• Mayo Clinic Nicotine Dependence Center
• MedlinePlus article on Smoking
• Society for Research on Nicotine and Tobacco
• U.S. Department of Health & Human Services on Smoking Cessation

Scientific references

1. Thorgeirsson Th. et al. Nature 2008 April 3. A variant associated with nicotine dependence, lung cancer and peripheral arterial disease. Nature 452, 638-642 (3 April 2008)

This content was last reviewed on February 11, 2010.