Nicotine May Accelerate Atherosclerosis, May Be as Dangerous as Tar

It's well known that smoking cigarettes increases risk for a host of serious health problems from cancer to heart disease. Now a new study from Weill Cornell Medical College in New York City looks at how they do their dirty work by contributing to atherosclerosis, or hardening of the arteries. The evidence points to nicotine, the addictive chemical in cigarettes.

By comparing reduced-nicotine cigarettes like Quest 3 and Eclipse with regular cigarettes, researchers discovered that the extent of cigarette-smoke induced atherosclerosis in mice correlated with the levels of nicotine - the higher the nicotine, the more disease.

"Right now, the general consensus is that the problem with cigarettes is tar and that nicotine is safe. That's why you can buy nicotine gum or patches to help you stop smoking. Our study presents new evidence that nicotine may not be safe at all, especially for your heart," says Dr. Daniel F. Catanzaro, principal investigator of the study, recently published in the journal Cardiovascular Toxicology. Dr. Catanzaro is associate research professor of physiology and biophysics in the Departments of Medicine and Cardiothoracic Surgery at Weill Cornell Medical College.

Previous studies have suggested that nicotine in cigarettes can hurt the heart by activating the sympathetic nervous system and increasing the heart rate - potentially leading to fatal arrhythmias. (Nicotine also affects most organ systems - including the gastrointestinal tract, the skin and the central nervous system.)

The new Weill Cornell study looked at two so-called "potentially reduced exposure products" (PREPs) - Eclipse and Quest. Eclipse cigarettes work by heating inhaled air to activate its contents without burning the tobacco. Quest cigarettes are made with tobacco that is genetically-modified to have lower nicotine. Eclipse and Quest 3 have nicotine yields of 0.2 and 0.05 mg per cigarette, respectively. This compares to the two regular cigarettes studied - 2R4F and Quest 1, with nicotine yields of 1 and 0.6 mg per cigarette, respectively. Eclipse and Quest cigarettes are marketed with the implication that they may be less harmful or addictive than conventional cigarettes. Quest cigarettes purportedly provide smokers the opportunity to taper their nicotine consumption by progressively moving to lower nicotine cigarettes. 2R4F is a research cigarette supplied by the University of Kentucky.

The study found that mice exposed to smoke from low-nicotine cigarettes had significantly smaller atherosclerotic lesions, compared to those exposed to regular cigarettes but still larger than lesions in control mice not exposed to cigarette smoke, which showed the least evidence of atherosclerosis. The accelerating effects of smoking on lesions was seen early, within weeks of smoke exposure.

"While our study seems to suggest that low-nicotine cigarettes are safer, we also know that smokers adjust their smoking habits to maintain their level of nicotine. In other words, if you switch to a low-nicotine product, you will probably increase the number of cigarettes you smoke, or change the way you smoke to get more nicotine out of each cigarette. The best thing to do is quit," says Dr. Catanzaro.