Smoking tinkers with your DNA, leaving a trail

September 22, 2016 Providence Health Team

It turns out that, in addition to all the other detrimental effects of smoking tobacco, the habit leaves tracks in your genes. And that may explain how smoking-related diseases develop even years after people quit the habit.

Researchers from the U.S. National Institute of Environmental Health Sciences studied the effects of smoking on what is called DNA methylation. These are potential changes in the way genes are activated, or turned on.

They found that smoking cigarettes can change the way some of your genes operate even decades after you quit. And the habit leaves biomarkers that give clinicians a way to determine how much and how long you’ve smoked.

Stephanie London, M.D., an author of the study and deputy chief of epidemiology at the USNIEHS, said the findings could be used to develop new tests to tell clinicians about their patients’ smoking histories. They also could lead to the development of targeted therapies for smoking-related illnesses.

"We could use this type of data to estimate people's previous smoking," she said. That will be useful for those working on therapies.

The way diseases such as cancer, chronic obstructive pulmonary disease and stroke develop years after a person stops smoking is not fully understood. But researchers think methylation may be the molecular mechanism that enables the process.

While the study focused on the long-term, hidden effects of smoking, even many years after you’ve quit, London emphasized that the sooner you quit, the better off you will be.

Another reason to quit: Parents who smoke are a big influence on whether their children will end up smokers. A study in 2014 found that teenagers whose parents currently smoked were 10 times more likely to become regular smokers or to try cigarettes at an early age than teens whose parents didn’t smoke.

Other hazards of smoking

Smoking has declined in the United States since the first Surgeon General’s report on the subject, in 1964. Yet the epidemic of smoking over the last century has been “an avoidable public health tragedy,” in the words of the Surgeon General’s 2014 report.

Among the report’s major conclusions were:

  • More than 20 million premature deaths in the United States since 1964 can be attributed to smoking.
  • Smoking has been found to causes disease in “nearly all organs of the body” and to harm unborn babies.
  • Secondhand tobacco smoke also causes cancer, and respiratory and cardiovascular diseases.
  • Health risks of smoking to women have risen to be on par with health risks to men.

To learn more

The study, “Epigenetic Signatures of Cigarette Smoking,” was published in the journal Circulation: Cardiovascular Genetics.

You’ve heard a lot about the damage smoking can do to your health and to the health of people around you. For deeper reading on smoking’s effects and for tips on how to quit, visit the U.S. Centers for Disease Control and Prevention’s page on “Smoking & Tobacco Use.”

You can also read the landmark “2014 Surgeon General’s Report: The Health Consequences of Smoking – 50 Years of Progress” at the CDC site.

Providence has many resources to help you quit smoking, from smoking cessation classes to nicotine-replacement medications. You can find a Providence provider in our multistate directory.

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