The study, released today by the National Institutes of Health National Cancer Institute, said that while smokers may think they are reducing their cancer risk by switching to the brands, there is no evidence risk is actually reduced.
While light cigarettes may measure as having less tar or nicotine, the study said smokers compensate by either smoking more cigarettes or smoking more deeply.
The study and anti-tobacco activists today called the use of the two terms a "scam" by tobacco makers "to intercept" smokers on the way to quitting.
The Federal Trade Commission, which currently tests cigarettes to see which can be identified as
Tobacco makers today denied that they are using the terms to claim light cigarettes carry less risk.
Philip Morris said its ads for lights carry a warning that the amount of tar and nicotine inhaled depends on smoking habits and that the terms "light" and "ultralight" are useful to consumers "as a point of reference."
Sharon Boyse, director of applied research at Brown & Williamson, said anti-tobacco groups are saying "that [if] tar levels don't differ at all, they're saying, in effect, smoke whatever you like."
Staff writer Cara B. DiPasquale contributed to this report.