Genes may be to blame for chain smoking

SMOKERS who find it hard to cut down or quit may be at the mercy of their genes, new research suggests.

Scientists identified three genetic mutations that increase the number of cigarettes people smoke a day.

Several also appear to be associated with taking up smoking, and one with smoking cessation.

Some of the findings will now be incorporated into risk factor DNA tests developed by the Icelandic company deCODE, which took part in the research.

A previous study two years ago found a common single-letter change in the genetic code linked to nicotine addiction and lung cancer risk.