WASHINGTON, July 22 (UPI) -- While electronic cigarettes may pose less health risk than cigarettes, they may be just as addictive or more because e-liquids contain the most addictive form of nicotine and many bottles of the liquid are mislabeled as to their level of the drug, according to new research.
A separate study found that gradually decreasing the amount of nicotine in cigarettes did not help smokers to quit, finding that only one person did so over the course of a year.
Electronic cigarettes are seen as a healthier alternative for smokers who don't want to actually kick the habit because rather than burning tobacco, liquids containing nicotine and flavorings are heated and vaporized. Researchers sought, in a study published in Chemical Research in Toxicology, to find the levels of nicotine in the liquids and what type of nicotine they contained.
Of the three types of nicotine, researchers found that all the brands of e-liquid they tested were the strongest form -- free-base nicotine that is easily absorbed by the body. More significantly, the researchers wrote that levels of nicotine contained in e-liquids often didn't match the label.
In a separate two-year study, published in the journal Addiction, reducing the level of nicotine in cigarettes was not shown to help people quit the habit.
"We don't 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 Dr. Neal Benowitz, a professor at the University of California San Francisco, in a press release.
Researchers recruited 135 smokers who were not interested in quitting, asking some to smoke cigarettes they were given and the rest to continue smoking their regular brand. Those in the experimental group were given cigarettes with progressively less nicotine in them over the course of 6 months, and then were asked to smoke the free, lower-nicotine cigarettes for 6 months.
Participants were followed for another year after the 6 months of low-nicotine cigarettes. Researchers found that almost none of the 153 people -- who had not been interested in quitting in the first place -- had reduced or quit their smoking.
The participants reported smoking about 20 cigarettes per day at the start of the study, and many who received research cigarettes reported this had plunged to about 13 per day. In many cases, researchers reported, people returned to their former brand and nicotine level when no longer being provided with the lower-nicotine option.
Benowitz said the study shows reducing nicotine alone doesn't help with nicotine addiction, but that a combination of tactics, including e-cigarettes, which have benefits over burning paper and tobacco., is required.
"Nicotine reduction would work best in the context of public education, easy access to smoking cessation services and the availability of non-combustible sources of nicotine for those who have difficulty stopping nicotine completely," Benowitz said.