Washington

Smokers puffing on low-tar cigarettes may be deluding themselves, according to the US Institute of Medicine (IoM). Research has yet to show that these modified cigarettes are any safer than their conventional counter-parts, a report by the IoM concludes.

In its study, the IoM found no evidence that using low-tar cigarettes reduces a smoker's exposure to carcinogens. And even if these cigarettes do lower the amount of carcinogens inhaled, there is also no evidence that this would necessarily reduce the smoker's susceptibility to disease.

“No one knows whether decreased exposure translates into decreased risk for disease,” says Stuart Bondurant, medical professor at the University of North Carolina, Chapel Hill, and chair of the IoM committee that studied the problem.

The independent panel made its assessment of the harm reduction potential of low-tar cigarettes and other nicotine products at the request of the US Food and Drug Administration (FDA). Its report, “Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction”, was published last week.

Cigarettes that are low in tar and nicotine raise a public health concern because they may use implied but unsubstantiated safety claims to keep smokers hooked on tobacco and attract new users, the report says. And there is no guarantee that the products reduce harmful exposure because the smokers tend to suck harder and smoke more frequently to maintain their nicotine levels.

The IoM panel found that more research is needed to establish whether there is a link between exposure reduction and harm reduction. Such research, it says, could improve understanding of dose-response relationships of specific smoke components, develop and validate biomarkers that link smoke exposure to disease risk, and explore the epidemiology of smoking and health.

The report also suggests preclinical studies to determine harmful smoke components and their pathogenic effects. For example, new genomic and proteomic technologies could be used to look at the effect of tobacco exposure on gene translation and expression in disease.

FDA-approved nicotine products were also examined by the panel. These include patches, sprays and chewing gum, which deliver pure nicotine at low doses. The products are approved only for short-term use to help smokers quit the habit, but research has not established long-term safety for those smokers using them to continue to get low levels of nicotine, the report says.

The report recommends new regulations requiring manufacturers to disclose ingredient, exposure and experimental data to back up any risk-reduction claims. But it did not suggest a particular agency to take on this regulatory task. It also emphasizes the need for a national, comprehensive surveillance system to monitor product characteristics and usage patterns.

Although both the National Institutes of Health and the tobacco industry have conducted some research into the health effects of the products covered in the report, the field is “in its infancy,” according to Peter Shields, a panel member and associate director of Georgetown University's Lombardi Cancer Center.

→ http://books.nap.edu/catalog/10029.html