Subjects: Public health
Levels of cancer-causing nitrosamines are higher in US-made cigarettes than those from other countries, according to scientists at the Center for Disease Control. That means they can potentially cause more cases of lung cancer.
To reach these conclusions, David Ashley and colleagues group measured mouth levels of a highly carcinogenic substance known as NNK, and urinary levels of its major metabolite, NNAL in 126 smokers from New York, Minnesota, Australia, Canada and England. The US smokers used several popular brands including Camel Light, Marlboro, Newport and Newport Light. The scientists counted butts to assure smokers from each location consumed the same numbers of cigarettes.
It turned out that 24 hour mouth levels of NNK (in nanograms) were 1,490 in New York, 1,150 in Minnesota, 1,010 in England, 449 in Canada and 350 in Australia. There was a direct correlation between mouth levels of NNK and urinary levels of NNAL.
Of note, 2 recent studies have shown a direct relation between urinary NNAL levels and lung cancer risk.
Together, these findings suggest that “higher levels of tobacco-related nitrosamines in the smoke of US cigarette varieties lead to higher mouth-level exposure to NNK and increased NNAL, which may be associated with excess lung cancer burden,” wrote the scientists.
The scientists also hypothesized that high levels of NNK in US tobacco products result from domestic curing processes and the blends of tobacco used during production.
Unfortunately, lowering nitrosamine levels in US cigarettes might not make them safer because that may increase the amounts of other carcinogenic substances.
As well, the scientists “did not look at the two dozen other cancer-causing toxins,” according to John Spangler of Wake Forest University. “And it did not examine chemicals that might affect heart disease, stroke, emphysema, and other diseases caused by tobacco use,” he added.
The findings appear in Cancer Epidemiology, Biomarkers & Prevention.