Scientists have pinpointed a genetic link that makes people more prone to tobacco, smoke more cigarettes longer, and develop deadly lung cancer

it may lay the groundwork for more tailored quit-smoking treatments

A smoker who inherits this genetic variation from both parents has an 80 per cent greater chance of lung cancer than a smoker without the variants, the researchers reported

And that same smoker on average lights up two extra cigarettes a day and has a much harder time quitting than smokers who don't have these genetic differences

The scientists surveyed genetic markers in more than 35,000 people in Europe, Canada and the United States, zeroing in on the same set of genetic differences