By Neil Wagner
Smokers often believe the damage smoking does to lungs is years away. The results from a new study paint an entirely different picture.
Researchers report that physical exams, lung function tests and chest x-rays are not sensitive enough to pick up early damage from smoking. In the study, 31 smokers who tested normal in every other way showed genetic changes in their lungs similar to those found in people with lung cancer. The findings suggest that lung damage is occurring much earlier than it is generally thought to be in smokers.
Cells lining the airways of the smokers' lungs, human embryonic stem cell genes had, according to the scientists, been turned on. These genes are normally active (turned on) in the developing embryo before cells are programmed with their specific assignment. The genes are then turned off as cells become specialized and normally will remain turned off for the rest of a person's life. But in all major lung cancers they are turned back on.
“The study doesn't say these people have cancer, but that the cells are already starting to lose control and become disordered,” Dr. Ronald G. Crystal, the study's senior investigator and professor of genetic medicine at Weill Cornell Medical College said in a statement. “The smoker thinks they are normal, and their doctor's exam is normal, but we know at the biologic level that all cigarette smokers' lungs are abnormal to some degree.”
To paraphrase Yogi Berra — it gets late real early once you start smoking.
In the study, 21 healthy nonsmokers were compared to 31 smokers who had no lung disease symptoms and had normal X-rays, as well as normal chest examinations. By sending a thin tube called a bronchoscope and a fine brush into the lungs, investigators gently brushed the inside of the airways to collect cells from the airway's epithelium (lining), the lungs' frontline defense against all invaders, including smoke particles. Researchers then genetically analyzed these cells, which are where lung cancer often begins. And they found noticeable changes.
“When you smoke a cigarette, some of the genetic programming of your lung cells is lost,” Dr. Crystal explains. “Your cells take on the appearance of a more primitive cell. It doesn't necessarily mean you will develop cancer, but that the soil is fertile to develop cancer.”
One reason younger people smoke is that they think they have time to quit later on before smoking does any significant damage. But research continues to find good reasons for quitting early. A study published earlier this year in the New England Journal of Medicine found that quitting smoking between the ages of 25 and 34 will add an average of ten years to your life.
Even if you happen to be over 60, there are still many health benefits awaiting you after you stop smoking.
The study is published online in Stem Cells and will also appear in a future print issue of the journal.
July 30, 2013