Tobacco companies adjusted the menthol levels in cigarettes in order to make them more appealing to young smokers, according to researchers from the Harvard School of Public Health.

The New York Times reported July 17 that the study stated, "Tobacco companies researched how controlling menthol levels could increase brand sales among specific groups. They discovered that products with higher menthol levels and stronger perceived menthol sensations suited long-term smokers of menthol cigarettes, and milder brands with lower menthol levels appealed to younger smokers."

Based on this research, tobacco firms manipulated "sensory elements of cigarettes to promote initiation and dependence" among young smokers. For example, the authors said, Philip Morris designed Marlboro Milds to have lower menthol levels to appeal to young smokers, while it boosted the menthol content in Marlboro Menthol to appeal to older smokers.

Philip Morris denied that menthol levels were manipluated to addict young smokers. "We disagree with the conclusions that menthol levels in our products were manipulated to gain market share among adolescents," said David M. Sylvia, a spokesperson for Philip Morris parent Altria. "We do not do research among, nor design products for, nor market to those who are underage. Our efforts are designed to appeal to current adult smokers, whether they are menthol smokers or non-menthol smokers."

The researchers based their conclusions on reviews of tobacco-industry documents and an analysis of how menthol levels in cigarettes varied over time.

Noting that 44 percent of teen smokers prefer menthol cigarettes, the study authors called for greater regulation of the tobacco industry and menthol cigarettes. In a major concession to tobacco companies, a bill pending in Congress that would give the Food and Drug Administration regulatory control over tobacco would exempt menthol from a broader ban on flavored cigarettes.

The study was published in the American Journal of Public Health.

* Correction notice (July 18, 2008): As originally published, the title erroneously stated "Tobacco Companies Manipulated Nicotine, Researchers Say." This study found that tobacco companies manipulated Menthol, as is now correctly noted.