Smokers could soon benefit from new drugs that improve the function of their lungs, owing to the lucky few who smoke for years with little consequence. UK researchers scanned 50,000 smokers and non-smokers, including some who suffer from chronic obstructive pulmonary disease, and identified gene mutations that enhance lung function.

Basically, smokers with these “good genes” had a lower risk of COPD while those with “bad genes” were more likely to develop the disease. This helps explain why non-smokers sometimes get sick, reports the Guardian.

A researcher tells the BBC the genes affect how lungs grow and react to damage. But “there doesn’t appear to be any kind of magic bullet that would give anyone guaranteed protection against tobacco smoke,” he adds.

A smoker with good genes “would still have lungs that were unhealthier than they would be had they been a non-smoker.” The study, which involved scanning 28 million genetic variants in each participant, also identified five sections of DNA more commonly found in smokers that may affect how easily a person can become addicted to nicotine.

That finding, however, still needs to be confirmed. The study offers “fantastic new clues about how the body works that we really had little idea about before and it’s those things that are likely to lead to some really exciting breakthroughs for drug development,” says a researcher.

More specifically, understanding how a person’s genes relate to disease and tobacco addiction can help scientists “design and develop better and more targeted treatments that are likely to be more effective and have fewer side effects,” a scientist adds.

Researchers hope to expand the study group to 500,000 in 2016, per a release. (A similar study found some smokers may have genes that repair damage.)

This article originally appeared on Newser: Why Some Smokers Don’t Get Lung Disease