In fact, "switching to ['light' cigarettes] for any reason is associated with continuing to smoke," said study author Dr. Hilary Tindle, a researcher at the University of Pittsburgh's Division of General Internal Medicine.

However, she acknowledged that the research does not prove that switching leads directly to a lower rate of quitting.

According to the authors, an estimated 84 percent of cigarettes sold in the United States are so-called low-tar and low-nicotine, with many of them called "lights." Some smokers may assume they're healthier than other cigarettes, but medical researchers say smokers still suck in about the same level of carcinogens. And research has shown that "lighter" cigarettes don't reduce smoking-related illness and death.

Regardless of what brand they smoke, "the average smoker dies 13 to 14 years earlier than he or she would die if he or she did not smoke," Tindle said.

In the new study, published online Nov. 3 in the journal Tobacco Control, researchers examined the results of a 2003 survey of 30,800 people in the United States who had smoked within the past year. Thirty-eight percent of them had switched to "lighter" cigarettes, with the largest percentage of those -- 26 percent -- saying they'd done so for better flavor. Forty-three percent mentioned one, two or three reasons for switching, with quitting smoking being one of those reasons.

However, those who had switched were 46 percent less likely to have quit smoking.

Why might switchers be more likely to continue smoking? "Prior research suggests that switching may resolve smokers' cognitive dissonance about smoking -- something along the lines of, 'Well, since I'm smoking a [supposedly] healthier cigarette, I really don't have to worry about lung cancer, heart disease, impotence, wrinkles, early death [fill in the blank] because my health is not at risk,'" Tindle said. "This type of rationale may keep more health-conscious smokers smoking."

But there are other possible explanations, added Robert West, a researcher who studies tobacco use at University College London in England. It's possible, for example, that people who switch are already more dependent on cigarettes and less able to quit, he said.

What to do? "In Europe, tobacco companies are not allowed to call cigarettes low tar or imply that they are in any way safer," West said.

Regardless of how cigarettes are marketed, Tindle said, "the best solution for the problem of how to live longer and healthier is to quit smoking now."

In related news, a study published Nov. 3 in the Journal of Epidemiology and Community Health finds that smoking during pregnancy is linked to a higher level of behavioral problems in offspring later in life, even among those as young as 3.

A team from the University of York in the England tracked 14,000 mother-and-child pairs and found that maternal smoking during pregnancy was associated with significantly higher odds for attention-deficit hyperactivity disorder (ADHD) and other behavioral woes, compared to children born to nonsmoking mothers.

More information

Find out more about smoking and its consequences at the U.S. Centers for Disease Control and Prevention.