Genetic variations put youth at higher risk for lifetime of tobacco addiction

These common gene variations, called single nucleotide polymorphisms (SNPs), are changes in a single unit of DNA. Scientists call SNPs that are linked and inherited together a haplotype. The researchers found that one haplotype for the nicotine receptor put European American smokers at greater risk of heavy nicotine dependence as adults, but only if they began daily smoking before the age of 17. A second haplotype actually reduced the risk of adult heavy nicotine dependence for people who began smoking in their youth.

The researchers studied 2,827 long-term European American smokers, recruited in Utah and Wisconsin, and to the National Heart, Lung, and Blood Institute's Lung Health Study. They assessed the level of nicotine dependence for all smokers, and recorded the age they began daily smoking, the number of years they smoked, and the average number of cigarettes smoked per day. DNA samples were taken from all smokers, and the researchers recorded the occurrence of common SNPs, grouped into four haplotypes, which had been identified earlier in a subset of participants.

They found that people who began smoking before the age of 17 and possessed two copies of the high-risk haplotype had from a 1.6-fold to almost 5-fold increase in risk of heavy smoking as an adult. For people who began smoking at age 17 or older, presence of the high-risk haplotype did not significantly influence their risk of later addiction. The high-risk haplotype is common in the three study populations, and European American populations in general, ranging in frequency from 38 percent to 41 percent.

Although the authors caution that different haplotype frequencies would likely be observed in different ethnic populations, Robert Weiss, Ph.D., professor of human genetics at the University of Utah and lead author of the study explains, "We know that people who begin smoking at a young age are more likely to face severe nicotine dependence later in life. This finding suggests that genetic influences expressed during adolescence contribute to the risk of lifetime addiction severity produced from the early onset of tobacco use."

According to Dr. Nora Volkow, director of the National Institute on Drug Abuse (NIDA), "In recent years we've seen an explosion in the understanding of how small genetic variations can impact all aspects of health, including addiction. As we learn more about how both genes and environment play a role in smoking, we will be able to better tailor both prevention and cessation programs to individuals." The study was funded in part by NIDA and the National Heart, Lung, and Blood Institute (NHLBI), parts of the National Institutes of Health (NIH).

The NIDA-funded 2007 Monitoring the Future Study showed that 7.1% of 8th graders, 14.0% of 10th graders, and 21.6% of 12th graders had used cigarettes at least once in the month prior to being surveyed. Although cigarette use has declined slightly in youth in recent years, just over 3 million young people between the ages of 12 and 17, or 13 percent of those in the United States, still smoke cigarettes.

Source: University of Utah

Parental warning: second-hand smoke may trigger nicotine dependence symptoms in kids
Parents who smoke cigarettes around their kids in cars and homes beware – second-hand smoke may trigger symptoms of nicotine dependence in children. The findings are published in the September edition of the journal Addictive Behaviors in a joint study from nine Canadian institutions.
Do 'light' cigarettes deliver less nicotine to the brain than regular cigarettes?
For decades now, cigarette makers have marketed so-called light cigarettes — which contain less nicotine than regular smokes — with the implication that they are less harmful to smokers' health. A new UCLA study shows, however, that they deliver nearly as much nicotine to the brain.
Exercise effective in helping pregnant women kick the habit
Exercise could be a useful tool in helping pregnant women to give up smoking, according to new research published today in the open access journal BMC Public Health. Despite the warnings, 17% of women in the UK and 20% of women in the US still admit to smoking during pregnancy. This often leads to lower birth weight, higher infant mortality, and is linked to learning difficulties, problem behaviour and asthma in childhood.
'Electronic' cigarettes leave WHO fuming
The World Health Organisation on Friday angrily denounced "bogus, untested, and false" claims that it endorses so-called electronic cigarettes as a means to stop smoking.
Genetic region linked to a 5 times higher lung cancer risk
A narrow region on chromosome 15 contains genetic variations strongly associated with familial lung cancer, says a study conducted by scientists at Washington University School of Medicine in St. Louis and other institutions in the United States and the United Kingdom.
Research suggests that cigarettes' power may not be in nicotine itself
There may be a very good reason why coffee and cigarettes often seem to go hand in hand. A Kansas State University psychology professor's research suggests that nicotine's power may be in how it enhances other experiences. For a smoker who enjoys drinking coffee, the nicotine may make a cup of joe even better. And that may explain why smoking is so hard to quit.
Newly-defined factors may prevent postpartum smoking relapse
Although many women quit smoking during pregnancy to protect their unborn children from the effects of cigarettes, half of them resume the habit within a few months of giving birth.
Trouble quitting?: New smoking study may reveal why
A new study from researchers at the University of Pittsburgh and Carnegie Mellon University sheds light on why smokers' intentions to quit "cold turkey" often fizzle out within days or even hours.

Genetic variations put youth at higher risk for lifetime of tobacco addiction

Related stories:

News discussion: