Young smokers can become addicted to nicotine within two days of first inhaling, according to a disturbing new study quoted in media reports Wednesday.

The study, conducted by a team of physicians from the University of Massachusetts Medical School, contradicts the belief that long-term smoking is necessary to develop an addiction.

"The importance of this study is that it contradicts what has been the accepted wisdom for many decades," said Dr. Joseph DiFranza, the lead author, "which is that people had to smoke at least five cigarettes a day over a long period of time to risk becoming addicted to nicotine." DiFranza is a professor of family medicine at the University of Massachusetts.

The study also finds children need only smoke seven cigarettes a month to report symptoms of dependence.

The definition of tobacco addiction is controversial, but the scientists used widely accepted criteria to diagnose dependence and a well-validated questionnaire to determine the extent to which smokers had allowed the habit to dictate their behavior.

The student volunteers were interviewed 11 times over a four-year period. They also took saliva samples to determine blood levels of nicotine and link them to addictive behavior.

Most of the youths began inhaling at just under age 13 (average age of 12.8 years), 38 percent developed tobacco dependence, and 70 percent had cravings that were difficult to control before they were smoking every day.

The study's authors urged that teenagers be warned that it might only take "one cigarette to initiate a life-long dependence on tobacco."

(Xinhua News Agency via Agencies August 1, 2007)