A new US study has shown it is possible to reduce smokers’ dependence on nicotine by gradually reducing the nicotine content of their cigarettes and thereby making it easier to quit altogether.

The study is the work of researchers at the University of California, San Francisco (UCSF), and San Francisco General Hospital Medical Center and is to be published in the November 14th issue of the journal Cancer Epidemiology, Biomarkers & Prevention, although it has not yet appeared in the early online edition.

Dr Neal Benowitz, professor of medicine, biopharmaceutical sciences, psychiatry and clinical pharmacy at UCSF, and co-leader, tobacco control program at UCSF Comprehensive Cancer Center, led the study and with his colleagues enrolled 20 healthy adult smokers to participate in the study.

The participants smoked their usual brand of cigarettes for a week and then switched to six weeks where they were given cigarettes with progressively diminishing amounts of nicotine. After this time they could go back to their usual brand, which most did.

However, when they were followed up a month later, the participants were smoking about 40 per cent fewer cigarettes a day compared to what they were smoking before the study. Also, one quarter of them gave up entirely during the course of the study.

Benowitz said their findings supported the idea that if tobacco companies were forced to reduce levels of nicotine in cigarettes, young people starting out as smokers could avoid becoming addicted, and older longer term smokers could quit or reduce their smoking. “This could spare millions of people from the severe health effects of long-term smoking,” he added.

The current system of tobacco companies offering products advertised as low nicotine alternatives does not change the level of nicotine that smokers absorb, said the researchers.

Congress is currently looking at bringing in legislation to give the Food and Drug Administration (FDA) powers to force tobacco companies to reduce nicotine yields in cigarettes so they would be less addictive, said Benowitz.

The new study counters the argument put forward by some experts that reducing the nicotine content of cigarettes would just cause smokers to smoke more of them, which would then increase health risks due to toxins, which is what happens with smokers who use the currently marketed low nicotine products, explained Benowitz.

Studies have shown that cigarettes currently marketed as low nicotine do not contain lower absolute levels of nicotine although they do reduce nicotine intake when they are tested by smoking machines. The total nicotine content of these cigarettes is still high, but the manufacturers use paper that is more porous and engineer the cigarettes to burn faster, so when smoked by a machine the nicotine yield over the course of the cigarette is lower than a comparable normal nicotine cigarette. However real smokers compensate by taking bigger and more frequent puffs, said the researchers.

The cigarettes used in the study had a lower total overall level of nicotine, so it was impossible, or very difficult, to compensate by taking bigger and more frequent puffs.

In this study Benowitz and colleagues also tested the participants’ exposure to carbon monoxide, carcinogens in the tobacco smoke, and risk factors for cardiovascular diseases. All levels of these variables stayed the same or went down, showing that the smokers were not taking in higher amounts of tobacco smoke toxins when they changed over to the reduced nicotine cigarettes.

Benowitz and another research colleague, Jack Henningfield, wrote a paper in the New England Journal of Medicine in 1994 suggesting that legislation should be brought in forcing manufacturers to gradually reduce the nicotine in all cigarettes on sale in the US.

The researchers are now in the process of setting up a larger scale clinical study to replicate the findings in a more robust way. They are also looking at whether reduced nicotine cigarettes reduce the potential for addiction among adolescents smokers who are still at the experimenting stage.

Click here for the journal Cancer Epidemiology, Biomarkers & Prevention.

Click here for UCSF website.

Written by: Catharine Paddock