Smoking gun. People with certain variations in the nicotine-receptor gene are at greater risk of becoming addicted to smoking in adulthood.
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Peer pressure can lead adolescents to start smoking, but their DNA keeps hooked on the buzz of nicotine in their adult lives. So says a new study that found that people with variations in specific genes are more likely to become addicted if they start smoking in adolescence. The work may explain why some people find it harder to quit smoking and also stresses the importance of preventing children from smoking in the first place.
Previous research has shown that people who start smoking in adolescence are more likely to be heavy smokers as adults; They also find it more difficult to quit than those who start first turn later in life. Some genes may influence whether people are hooked on cigarettes during their teenage years, but no one had shown that. Three recent studies have shown that people with only one change of base nucleotides in genes encoding cell receptors that bind to nicotine - the chemical addictive in cigarettes - were more likely to develop lung cancer ( Science NOW, April 2). Because genes help produce the buzz of nicotine, a team led by Robert Weiss, a geneticist at the University of Utah in Salt Lake City, wanted to determine whether the variations in their sequences determine if people develop stronger addiction to cigarettes.
The research team compared the genes of receptors 2827 adults currently smoke more than a pack a day and have been enlightening on average for more than 30 years. 1051 smokers who started smoking at 16 or younger were 1.5 times more likely to have an addiction to nicotine worse if they had a particular pattern of six changes from a single base in the genes than those with other genetic models. However, subjects who had the same gene pattern, but started smoking after 16 years had no increased risk of a more severe habit, suggesting that addiction risk window of this particular genetic variation opens only during the teen years, the researchers report today in PLoS Genetics .
It is unclear how the genetic variant increases the chances of being caught young smokers. One possible explanation is that the adolescent brain responds differently to nicotine. "It could be that your brain matures, you become less susceptible to the addictive effects of nicotine because the genetic component that affects how nicotine interacts with these receptors may have less effect," said Chris Amos, genetic epidemiologist at University of Texas MD Anderson Cancer Center in Houston, who was not involved in the study.
Norman Edelman, a pulmonologist at the medical Center of Stony Brook University in New York, said the results show highlight the need to focus more on preventing adolescents from smoking. "most smokers, perhaps 0%, are hooked on cigarettes as adolescents or young people," he notes. "We spend a lot of 'efforts on smoking cessation in adults, but we do not spend enough on the prevention of smoking among children, which is really important because this place where the damage is done, according to this study. "
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