The move to lower-tar cigarettes in the United States over the past few decades may be linked to an increased risk of a type of lung cancer called adenocarcinoma, according to a preliminary study.
Dr. David Burns, of the University of California, San Diego, and colleagues found that the increase in adenocarcinoma tumors was higher in the U.S. than in Australia, even though low-tar cigarettes were introduced in both countries at the same time.
"The most likely explanation for it is a change in the cigarette," Burns told the Associated Press.
He noted that Australian cigarettes contain lower levels of cancer-causing nitrosamines than those sold in the U.S. Levels of nitrosamines -- a by-product of tobacco processing -- vary due to a number of factors, including different curing methods.
The findings were presented at a meeting of the Society for Research on Nicotine and Tobacco.