Smoking causes significant damage to the genome.

Bad news for current and past smokers: New research by scientists indicates that for every 15 cigarettes smoked...cigaretteYour genome will mutate once. Even if you quit smoking, you can't step into a safe zone from disease. Accordingly, habitssmokeLeaves will leave damaging "footprints" on your genes for three decades.

For every 15 cigarettes you smoke, your genes mutate once. (Image: Internet)

This is caused by DNA methylation, an epigenetic process in which a methyl group is inserted into DNA, altering its function. Abnormal DNA methylation may be a cause of cancer and cardiovascular disease.

Although the number of smokers has decreased each year, it remains the leading cause of preventable deaths worldwide. A key reason is that even after quitting, you remain at high risk of many serious diseases, even decades later. Cancer, cardiovascular disease, and chronic obstructive pulmonary disease (COPD) continue to threaten those who thought they were safe after quitting.

Scientists collected blood samples from nearly 16,000 volunteers, including both smokers and those who had quit smoking a long time ago. Analyzing DNA methylation patterns in their genomes, the scientists found that up to 7,000 genes would be affected by smoking.

Most of these methylation patterns disappear about five years after a person has quit smoking. However, in some cases, DNA methylation persists in their genes for up to three decades. Some of these have been shown to be responsible for the development of cancer and cardiovascular disease.

However, if you're still smoking in your 50s, it's not too late to make a change. "The encouraging news is that once you stop smoking, most DNA methylation signals return to normal levels within five years. This means your body is also working to heal the harmful effects of smoking."