Smokers often choose light cigarettes as a way of lessening the damage to their bodies and abating their guilt. Light cigarettes do contain less tar and nicotine than the regular versions, but that does not mean a person who smokes them inhales less of those compounds, according to past research and a new study from Japan.

What they wanted to know: Do people who smoke light cigarettes have lower levels of nicotine in their bodies than people who smoke regular cigarettes?

What they did: The researchers wanted to examine nicotine levels in Japanese males, over half of whom smoke regularly. They studied a group of about 450 male smokers who filled out a questionnaire about their smoking habits and gave a urine sample. The scientists measured the amount of a chemical called cotinine in the urine sample; cotinine is manufactured by the body with nicotine and often used as a marker of nicotine levels.

What they found: Men who smoked light cigarettes did have a lower concentration of cotinine, but not nearly as low as might be expected given the reduced nicotine in the cigarettes. Though "light" cigarettes have up to 11 times less nicotine than regular cigarettes, the men who smoked them reduced the amount of cotinine in their urine by only about half.

What it means to you: These researchers corroborate previous studies, which have concluded that no matter how you slice it, smoking is bad for your health. Since the 1980s, studies have shown that low-tar, low-nicotine cigarettes pose just as much of a threat as their high-tar, high-nicotine cousins. Doctors think that even though light cigarettes may appear more healthful, people smoke them more often, inhale deeper, or take more puffs off those types.

Caveats: This particular study was done only in Japanese males, and so technically it can't be extrapolated to include a larger population. However, because other studies have come to similar conclusions, it's safe to say that these results probably apply to nearly everyone.

Find out more: One of the weirdest, and perhaps most caustic, websites with facts about the tobacco industry is http://www.thetruth.com. It is under an umbrella organization, the American Legacy Foundation, created in 1998 as part of a major settlement between tobacco companies and 46 U.S. states to promote anti-smoking campaigns. Another good place for facts about nicotine, presented in a more traditional manner than those on thetruth.com, is the National Institute on Drug Abuse.

Read the article: Nakazawa, A., Shigetal, M., Ozasa, K. "Smoking Cigarettes of Low Nicotine Yield Does Not Reduce Nicotine Intake as Expected: A Study of Nicotine Dependency in Japanese Males." BMC Public Health. 20 July 2004, Vol. 4, No. 28.

Full article available free online: http://www.biomedcentral.com