November 11, 2005

Oral tobacco not safe substitute for smoking

By Megan Rauscher

NEW YORK (Reuters Health) - Smokeless oral tobacco products such as moist snuff and hard snuff lozenges are not a safe alternative to cigarettes for people trying to kick the habit, as these products contain high levels of cancer-causing compounds.

Instead, the best aids appear to be medicinal nicotine replacement products such as the nicotine patch or gum as these products contain only trace amounts of cancer-causing compounds, according to research presented at a cancer prevention conference in Baltimore this month.

Dr. Stephen Hecht and colleagues from the University of Minnesota Cancer Center in Minneapolis compared the levels of cancer-causing nitrosamines in popular smokeless tobacco products and medicinal nicotine products such as the nicotine patch, nicotine gum, and nicotine lozenges.

The results "clearly showed that the levels of cancer-causing nitrosamines are far higher in smokeless tobacco products than they are in medicinal nicotine products," Hecht said during a press briefing.

Nitrosamine levels were highest in oral snuff tobacco products made in the US, following by Swedish 'snus' (another type of smokeless tobacco), whereas the lowest levels were found in hard snuff lozenges. The snuff lozenges actually did "quite well in our study -- it does appear to have lower levels of carcinogenic nitrosamines" than most of the other smokeless tobacco products, Hecht said.

By contrast, only trace amounts of these cancer-causing nitrosamines were found in the nicotine patch and gum.

While smokeless tobacco has "demonstrably less carcinogens and toxins than cigarette smoke," said Hecht, smokeless tobacco still has "remarkably high levels of carcinogenic tobacco-specific nitrosamines -- levels that are 100 to 1,000 times higher than in any other consumer product that is designed for oral consumption."

In a separate study, the team evaluated carcinogen biomarker levels in individuals using these products. They had 54 users of popular US smokeless tobacco products use their usual brand for two weeks and then had them switch to either Swedish snus or a nicotine patch for four weeks.

The team found that carcinogen levels in urine were statistically significantly lower after the switch from US-made smokeless tobacco brands to snus or to the nicotine patch. When comparing snus users to patch users, levels of cancer-causing compounds were significantly lower in patch users, indicating that medicinal nicotine is safer than snus, Hecht said.

These results conflict with some prior studies that suggested that smokeless tobacco including moist snuff may be a less harmful habit than cigarette smoking because many of the carcinogens in cigarette smoke are either reduced or absent in smokeless tobacco.

The bottom line, Hecht said, is that "smokeless tobacco products are dangerous."

"The evidence suggests," he continued, "that smokeless products are in fact a cause of oral cancer and pancreatic cancer in humans. The current evidence does not support smokeless tobacco as a substitute for cigarette smoking."