The international team of researchers reviewed studies that looked at genetic links to smoking and pulled together a “genetic risk profile” for smoking.

The researchers applied this to a long-term study of 1000 Australians born in the early 1970s. Information on participants’ smoking behaviour was analysed alongside DNA samples, which identified those who matched the smoking risk profile.

Although the genetic risk score was unrelated to starting smoking, having a high-risk genetic profile predicted increased likelihood of heavy smoking and nicotine dependence among those who did try cigarettes.

The link was strongest for teenagers who tried cigarettes – those with a high-risk genetic profile were 24 percent more likely to become daily smokers by age 15, and 43 percent more likely to become pack-a-day smokers by age 18.

 As adults, those with high-risk genetic profiles were 22 percent more likely to fail in their attempts at quitting.

 “The effects of genetic risk seem to be limited to people who start smoking as teens. This suggests there may be something special about nicotine exposure in the adolescent brain, with respect to these genetic variants,” said the lead researcher, Dr Daniel Belsky of North Carolina’s Duke University in the US.

Tobacco control expert Dr Marewa Glover says the study reinforces the value of policies aimed at preventing young people from starting smoking.

Source: The New Zealand Herald