Marlboro cigarettes, the world’s most popular brand, contained much higher levels of some cancer-causing substances than non-U.S. brands sold abroad, according to a new study by the U.S. Centers for Disease Control and Prevention.
The compounds typically were two to 22 times more concentrated in the smoke of Marlboros than of the local brands, according to the CDC study, which appears today in the journal Nicotine and Tobacco Research. The study compared concentrations of tobacco-specific nitrosamines, the most abundant and, according to experts, among the most significant carcinogens in tobacco smoke.
The cigarettes were purchased in 2000 and 2001 in the U.S. and 13 other countries, including China, India, Indonesia and Russia. A spokesman for Philip Morris USA, which produces Marlboro, said the firm during the last year has cut nitrosamine levels by working with growers to improve tobacco curing methods.
The CDC report is the first major study to suggest that Western-style brands could be more hazardous than the locally produced cigarettes. The study focused on Marlboro because it is the most popular cigarette in the U.S. and the world.
According to David Ashley, lead author of the study, nitrosamine levels in Marlboro are similar to those of most other American brands, which generally contain more of the compounds than do foreign cigarettes because of the tobacco blends used. For that reason, the study is likely to fuel criticism of marketing efforts by tobacco companies in the developing world -- which was a major impetus for a new tobacco control treaty, sponsored by the World Health Organization, that seeks a global ban on cigarette advertising.
Although tobacco companies say they are just trying to compete for sales in countries where people already smoke, critics contend that their marketing prowess will cause higher rates of smoking in the developing world.
Tobacco-specific nitrosamines are formed during the processing and burning of tobacco. There are five groups of suspected carcinogens in cigarette smoke, but most experts consider nitrosamines to be one of the two most important.
Their levels can be controlled. Virginia-based Star Scientific Inc. has developed a curing process that greatly reduces the amount of the chemicals in tobacco leaf. Two reduced-nitrosamine cigarettes -- Omni, made by Vector Group, and Advance, by Brown & Williamson Tobacco Corp. -- are in test markets.
Ashley said in an interview Thursday that there was no proof that lowering nitrosamines by itself would reduce cancer rates. But “if it is technically feasible to reduce levels of carcinogens in tobacco, we should reduce levels of carcinogens in tobacco,” Ashley said. “That’s simply good public health practice.”
The CDC researchers analyzed 15 packs each of Marlboros and a local brand in the U.S. and 13 other countries. The local brands purchased in two countries -- Mexico and Brazil -- had higher concentrations of nitrosamines than did Marlboros. The Marlboros were 30% higher in nitrosamines than their Russian rival and two to 22 times higher than brands purchased in Japan, China, Indonesia, India, Bangladesh, Germany, Pakistan, Egypt, Nigeria and Kenya, the study found.
The Campaign for Tobacco-Free Kids, a Washington-based anti-smoking group, said the study findings were the latest example of “the tobacco industry’s reckless disregard for the health of smokers.”
The group said high nitrosamine levels in U.S. cigarettes could help explain why lung cancer rates have not fallen as expected with overall reductions in levels of tar, of which nitrosamines are one component.
The study noted that nitrosamine levels may have increased in the late 1960s and early ‘70s, when direct-fire burners fueled by propane gas came into wide use for curing tobacco. The burners exhaust gases directly into the curing barns, exposing tobacco to gases that are precursors of nitrosamines.
Brendan McCormick, a Philip Morris spokesman, said the firm moved to address the risk in 2000, when it invested $35 million to convert barns to an indirect curing method. The result, he said, is an 80% to 90% reduction in nitrosamines in the 2002 tobacco crop, McCormick said.
“I don’t want to oversell the progress,” he said, but “it’s delivering results.”
Matthew Myers, president of the Campaign for Tobacco-Free Kids, said the study was further evidence of the need to grant authority to the Food and Drug Administration to regulate cigarettes -- including design changes that might raise or reduce health risks.
Alone among major tobacco firms, Philip Morris also is pushing FDA legislation, though with less-stringent terms than those sought by anti-smoking groups.