Since 1964, 29 surgeon generals have issued reports on the dangers of tobacco use, calling it the single most avoidable cause of disease, disability and death in the United States.

Despite these efforts to educate the public, the 2007 Smoker Misperceptions survey reveals there are significant differences between what smokers believe are the risks associated with smoking and the realities of tobacco-related disease and death.

Researchers from the American Legacy Foundation and GlaxoSmithKline Consumer Healthcare examined the responses of 900 adult men and women smokers in the U.S. who smoke cigarettes every day. The "average" respondent in the survey was 48 years old, started smoking at the age of 16 and currently smokes 20 cigarettes -- one pack -- per day.

Some of the data gathered from the survey indicates how ill-informed smokers are:

— Sixty-six percent didn’t know that their chance of developing lung cancer was greater than that of a non-smoker.

— Forty percent incorrectly believed that developing lung cancer depends primarily on genes, not on behaviors like smoking.

— Eight percent didn’t know that smoking has been proven to cause blindness.

— Ten percent didn’t know that smoking has been proven to cause hair loss.

— Twenty-six percent didn’t know that smoking has been proven to cause impotence.

— Thirty-three percent mistakenly thought that they could reverse the harmful effects of smoking by exercising and taking vitamins.

Dr. Richard D. Hurt, of the Nicotine Dependence Center at the Mayo Clinic, knows first hand about the myths that have developed around smoking.

Hurt, who is involved with EX, an online support group for smokers who wish to quit, said the following are the five most common misconceptions about smoking:

1. Myth: Nicotine causes cancer.

Fact: Nicotine is not a carcinogen. However, there are 4,000 known chemicals in cigarettes, and more than 60 of them are carcinogens.

2. Myth: Smoking is just a bad habit that you can stop at any time.

Fact: There is a habit component to smoking, but there are also biological changes to the brain that create the addiction.

Nicotinic acetylcholine receptors, which occur naturally in the brain, are activated when nicotine is consumed. The activation period is followed by a desensitized state in which the receptors become unresponsive. As more nicotine is consumed, and the number of unresponsive receptors increases, the smoker experiences less pleasure from each cigarette. This makes it necessary to increase the number of cigarettes smoked to achieve the desired level of pleasure.

3. Myth: Low nicotine cigarettes are safer.

Fact: The blend of tobacco in a low nicotine cigarette is exactly the same as in a regular cigarette. The reason cigarette companies can call them "low" has to do with the way nicotine levels are tested.

As the regulator of cigarettes, the Federal Trade Commission tests for nicotine and tar levels with machines that draw air through a cigarette in two-second puffs, repeated once per minute, until the cigarette is burned to the filter. The smoke that is generated in this manner tests low in nicotine.

However, this test doesn’t approximate the way people really smoke. Smokers will compensate for the lower yield of nicotine by puffing more, or taking longer drags. Consequently, the smoker will actually inhale the same or more nicotine and tar, even though it is considered a low-nicotine cigarette.

Another reason the machine tests are considered inaccurate is cigarette manufacturers put ventilation holes in the filters. These holes allow more air to be drawn in, which dilutes the smoke going into the machine, making it seem as though the cigarette being tested contains less tar and nicotine. But when people actually smoke these cigarettes, their fingers generally cover the holes in the filters.

4. Myth: Medicinal nicotine found in nicotine patches and nicotine gum is just as addictive as smoking.

Fact: The delivery system used to bring nicotine to the brain is what determines the level of addictiveness. Medicinal nicotine is released slowly through the venous system. The brain receives only small quantities, reducing the potential for addiction.

Inhaling brings nicotine to the brain extremely fast, which is why it is so addictive.

“Inhaling gets nicotine to the brain within five heartbeats,” Hurt said.

5. Myth: A smoker who tries to quit without assistance can maintain abstinence over the long term.

Fact: Chances of long-term abstinence for smokers who try to go it alone are less than 5 percent. With assistance, the smoker’s chance of staying away from cigarettes increases to 30 to 35 percent.