Over the years, smoking has been proven to cause dreading diseases that can lead to death. After a series of testing and deeper experimentation, scientists have found out another dangerous effect of smoking on human's DNA.
"Our study has found compelling evidence that smoking has a long-lasting impact on our molecular machinery, an impact that can last more than 30 years," said Roby Joehanes of Hebrew SeniorLife and Harvard Medical School.
Reviewing results from blood samples taken from almost 16,000 people, the researchers also have proven that for those who stopped smoking, their DNA modification was back to normal after five years.
"Although this emphasizes the long-term residual effects of smoking, the good news is the sooner you can stop smoking, the better off you are," said study author Dr. Stephanie London, deputy chief of the epidemiology branch of the U.S. National Institute of Environmental Health Sciences.
DNA Methylation
A study published online in the American Heart Association's journal Circulation: Cardiovascular Genetics found that smoking leaves its "footprint" on the genome through DNA methylation, the process by which cells control gene expression.
The researchers found out that the smokers have methylation patterns that can alter almost 7,000 genes due to smoking and if smokers quit, some genes are returned to normal but others are permanently damaged. The genes affected are the source of heart diseases and cancers.
Identifying the DNA-related genes can be the first step of evaluating the smoking pattern of the patient. London said, "We could use this type of data to estimate people's previous smoking. No one says they smoke when they don't, but they say they don't smoke when they do, so we could use these signals to find that out."
Though DNA return back to normal after five years of quitting smoking, some damages retain up to 30 years. Researchers were able to determine the gene that is highly affected and concluded that they are still at risk of getting life-threatening diseases.
Smoking And Its Long-term Effects
Dr. Norman Edelman, senior scientific advisor for the American Lung Association, said the new research raises alarming issues. Edelman wants to study how the genes and smoking are related and raise awareness of what smoking can do.
"The message here is that smoking has an enormous, widespread impact on your genes," Edelman explained. "Most of it is reversible, but some is not. So if you smoke, you're going to alter your genetic makeup in a way that's not totally reversible."
