New York, July 22 (IANS): Simply reducing the nicotine content of cigarettes may not be enough to make smokers kick the habit, shows new research.

"We do not know that very low nicotine cigarettes will not work to reduce nicotine dependence and enhance quitting, but progressively reducing nicotine content of cigarettes in the way we did, without other means of supporting smokers, did not produce the desired results," said lead study author Neal Benowitz from University of California San Francisco in the US.

The US Food and Drug Administration (FDA) is supporting research into how very low nicotine content (VLNC) cigarettes might function as a regulatory measure to make cigarettes non-addictive, reduce smoke exposure, and improve public health, even among people who do not want to quit smoking.

However, the new research published in the scientific journal Addiction showed that progressively reducing nicotine content in cigarettes may not eliminate smoking dependence.

In this two-year study involving 135 smokers, those in the test group smoked five levels of progressively lower nicotine content cigarettes over the course of one year, the lowest nicotine-content cigarette being smoked for seven months.

Participants in the control group smoked their usual brand of cigarettes for 12 months. All participants were then followed for another 12 months after returning to their own cigarettes or quitting.

During the 12-month follow-up, the lower levels of cotinine (a nicotine derivative found in plasma that provides an accurate record of the nicotine intake from smoking in recent days) in test group participants returned to levels similar to smokers in the control group, suggesting that they had returned to their former levels of smoking.

Quitting remained low: at 24 months the percent of smokers in the test group who quit smoking was not significantly higher than that of the control group.