Ever wonder why some teens who try cigarettes get hooked
quickly and others don't? The answer may lie in their genes, according to a new
study that spans nearly four decades.
Researchers used data from earlier studies to construct a
genetic risk score for heavy smokers. Next, they screened the genes of about 1
000 New Zealanders from birth to age 38 to see whether those with high risk
scores got hooked on cigarettes more quickly as teens and whether they had a
harder time kicking the habit as adults.
Teens with a high-risk genetic profile who tried smoking were
24% more likely to become daily smokers by age 15 and 43% more likely to smoke a
pack a day by the time they were 18, the study showed.
These high-risk participants were also 27% more apt to become
hooked on nicotine and 22% more likely to fail their quit-smoking attempts as
adults, when compared to people with lower scores. Participants with high-risk
gene scores had smoked about 7 300 more cigarettes than the average smoker by
age 38, the study showed.
A person's genetic risk profile did not predict whether they
would try cigarettes. About 70% of study participants had tried smoking. Those
who did try cigarettes and had a high-risk gene score were more likely to become
heavy smokers. The risk score was a greater predictor of becoming a smoker than
family history, the study showed.
"These genes accelerate the progression of smoking behaviours
among adolescents," said study author Daniel Belsky, a postdoctoral research
fellow at Duke University's Center for the Study of Aging and Human
"Most participants had tried smoking cigarettes when they were
around 15, but most did not go on to become heavy smokers," he said.
There was no relationship between these genes and risk of
becoming a heavy smoker when people took up smoking as adults. The crucial
window appears to be in the teen years, said Belsky, also with the Duke
University Institute for Genome Sciences & Policy.
"Adolescent manifestations of genetic risks are critical. If we
can intervene and prevent teens from becoming smokers, we may be able to protect
them for their whole lives," he said.
Anti-smoking campaigns that target youth are on the right
track, he said. The next step is to find out how these genes influence smoking
risk, and see if new quit-smoking drugs that interfere with the process can be
Another expert talked about adolescents and smoking
"These gene factors are critical for the rapid progression of
smoking among teens," said Dr Len Horovitz, a pulmonary specialist at Lenox
Hill Hospital, in New York City.
"It's clear that there is a window of time where we can
intervene and stop the progression of a teen becoming a heavy smoker," Horovitz
said. "The previous thinking was that people who couldn't quit had just been
smoking for too long." Instead, "it is a predestined, predetermined genetic
factor that turns many teen smokers into lifelong heavy smokers."
Want to quit smoking, but don't know how? Visit
Centers for Disease Control and Prevention.