Tobacco is a plant grown for its leaves, which are smoked, chewed, or sniffed for a variety of effects. It is considered an addictive substance because it contains the chemical nicotine.

In addition to nicotine, tobacco contains over 19 known cancer-causing chemicals (most are collectively known as "tar") and more than 4,000 other chemicals. These include acetone, ammonia, carbon monoxide, cyanide, methane, propane, and butane.

Over 38 million people in the United States have successfully quit smoking. Yet there are still around 50 million Americans who smoke. The majority say they would like to quit.

And, while the number of cigarette smokers in the United States has dropped over recent years, the number of smokeless tobacco users has steadily risen. This trend is likely related to the false belief that smokeless tobacco is safe. It is NOT. Smokeless tobacco carries many of the same health risks as cigarettes. Some people who want to stop smoking, but who still crave the nicotine, turn to smokeless tobacco wrongly thinking that they are doing something good for themselves.

THE EFFECTS OF NICOTINE

• Nicotine acts as both a stimulant and depressant on your body. It increases your bowel activity, saliva, and bronchial secretions. It stimulates the nervous system and may cause tremors in the inexperienced user, or even convulsions with high doses.
• After stimulation, there's a phase that depresses the muscles in your airways. As a euphoric agent, nicotine causes relaxation from stressful situations.
• On average, tobacco increases your heart rate 10 to 20 beats per minute, and it increases your blood pressure reading by 5 to 10 mmHg (because it constricts the blood vessels).
• Nicotine may also cause sweating, nausea, and diarrhea. Nicotine elevates the blood level of glucose (blood sugar) and increases insulin production. Nicotine also tends to enhance platelet aggregation, which may lead to blood clots.
• Nicotine temporarily stimulates memory and alertness. People who use tobacco frequently depend on it to help them accomplish certain tasks at specific levels of performance. Nicotine also tends to be an appetite suppressant. (For this reason, fear of weight gain also influences the willingness of some people to stop smoking.)

Finally, tobacco is highly addictive. It is considered mood and behavior altering. Tobacco is believed to have an addictive potential comparable to alcohol, cocaine, and morphine.

HEALTH RISKS

There are many reasons to quit using tobacco. Knowing the serious health risks may help motivate you to quit. When used over a long period, tobacco and related chemicals such as tar and nicotine can increase your risk of:

• Blood clots, which may lead to aneurysms and strokes
• Cancer (especially in the lung, mouth, larynx, esophagus, bladder, kidney, pancreas, and cervix)
• Coronary artery disease, including angina and heart attacks
• Decreased ability to taste and smell
• Delayed wound healing
• High blood pressure
• Lung problems such as emphysema and chronic bronchitis
• Pregnancy-related problems, including miscarriage, premature labor, low birth weight, and risk for sudden infant death syndrome ( SIDS)
• Tooth and gum diseases

You have the same risks if you use smokeless tobacco (chewing tobacco, snuff, etc.) for a long time. In addition, smokeless tobacco users have a 50 times greater risk for mouth cancer than those who do not use such products.

SECONDHAND SMOKE

Those who are regularly around the smoke of others (secondhand smoke) have a higher risk of:

• Coronary artery disease
• Lung cancer
• Sudden and severe reactions, including those involving the eye, nose, throat, and lower respiratory tract

Infants and children that are exposed regularly to secondhand smoke are at risk of:

• Asthma
• Infections, including virus-caused upper respiratory infections, ear infections, and pneumonia
• Lungs that do not work as well (poor lung function)
• Sudden infant death syndrome (SIDS)

TIME TO QUIT

There are a lot of ways to quit smoking and many resources to help you. Family members, friends, and coworkers may be supportive or encouraging, but the desire and commitment to quit must be your own.

Most people who have been able to successfully quit smoking made at least one unsuccessful attempt in the past. Try not to view past attempts to quit as failures, but rather as learning experiences.

Feel ready to quit? Here are some tips:

• List the reasons you want to quit. Include both short- and long-term benefits.
• Ask your health care provider for help. Find out whether prescription medications might help. Also ask about nicotine patches, gum, and sprays.
• Ask your family, friends, and coworkers for support.
• Set a quit date, and get rid of all of your cigarettes by that date.
• Quit completely -- cold turkey.
• Get more exercise. It relieves the urge to smoke.
• Learn self-hypnosis from a qualified practitioner. This helps some people.
• Make a plan about what you will do, instead of smoking, when stressed or other times you have the urge for tobacco. Be as specific as possible.
• Avoid smoke-filled settings and situations in which you are more likely to smoke.

Like any addiction, quitting tobacco is difficult, particularly if you are acting alone. If you join smoking cessation programs, you have a much better chance of success. Such programs are offered by hospitals, health departments, community centers, and work sites.

The best quit-smoking programs combine multiple strategies, including peer support and ways to overcome potential relapse situations. Counseling by telephone can be a very helpful reinforcement, even as effective as face-to-face counseling.

Short-term use of the antidepressant medication bupropion (Wellbutrin, Zyban), along with a quit-smoking program, may increase your success. Bupropion requires a prescription from your health provider and should not be used if you have a history of seizures or kidney failure.

If you aren't successful the first time, simply look at what occurred or what didn't work, develop new strategies, and try again. Many attempts are often necessary to finally "beat the habit."

THE BENEFITS OF QUITTING

• Within 20 minutes of quitting - your blood pressure and pulse rate drop to normal and the temperature of your hands and feet increases to normal.
• Within 8 hours of quitting - your carbon monoxide levels drop and your oxygen levels increase, both to normal levels.
• Within 24 hours of quitting - your risk of a sudden heart attack decreases.
• Within 48 hours of quitting - nerve endings begin to regenerate and your senses of smell and taste begin to return to normal.
• Within 2 weeks to 3 months of quitting - your circulation improves and walking becomes easier; even your lung function increases up to 30%.
• Within 1 to 9 months of quitting - your overall energy typically increases and symptoms like coughing, nasal congestion, fatigue, and shortness of breath diminish; also, the small hairlike projections lining your lower airways begin to function normally. This increases your lungs' ability to handle mucus, clean the airways, and reduce infections.
• Within 1 year of quitting - your risk of coronary heart disease is half that of someone still using tobacco.
• Within 5 years of quitting - the lung cancer death rate decreases by nearly 50% compared to one pack/day smokers; the risk of cancer of the mouth is half that of a tobacco user.
• Within 10 years of quitting - your lung cancer death rate becomes similar to that of someone who never smoked; precancerous cells are replaced with normal cells; your risk of stroke is lowered, possibly to that of a nonuser; your risk of cancer of the mouth, throat, esophagus, bladder, kidney, and pancreas all go down.

WHEN TO CONTACT A MEDICAL PROFESSIONAL

Call your doctor if you are a smoker and:

• You want an individual health risk profile
• You want to learn about methods to stop tobacco use
• You are pregnant, planning a pregnancy in the future, or using birth control pills
• You have symptoms of specific diseases associated with tobacco use (even if you are a nonsmoker exposed to secondhand smoke)

Other resources include local chapters of the American Lung Association and the American Cancer Society. Both organizations have a wide range of resource materials and comprehensive smoking cessation programs.

Metz CN, Gregersen PK, Malhotra AK. Metabolism and biochemical effects of nicotine for primary care providers. Med Clin North Am. 2004;88:1399-1413.

Anderson JE, Jorenby DE, Scott WJ, Fiore WC. Treating tobacco use and dependence: an evidence-based clinical practice guideline for tobacco cessation. Chest. 2002;121:932-941.

Parkes GT, Greenhalgh T, Griffin M, Dent R. Effect on smoking quit rate of telling patients their lung age: the Step 2 quit randomised controlled trial. BMJ. 2008:336:598-600.