Cigarette smoke causes harmful changes in the lungs even at the lowest levels

Aug 20, 2010

Casual smokers may think that smoking a few cigarettes a week is "no big deal." But according to new research from physician-scientists at NewYork-Presbyterian Hospital/Weill Cornell Medical Center, having an infrequent smoke, or being exposed to secondhand smoke, may be doing more harm than people may think. The findings may further support public smoking bans, say the authors.

According to a new study published today in the , being exposed to even low-levels of cigarette smoke may put people at risk for future lung disease, such as lung cancer and (COPD).

Epidemiological studies have long shown that is dangerous, but there have never been conclusive biological tests demonstrating what it does to the body at a gene function level, until now.

"Even at the lowest detectable levels of exposure, we found direct effects on the functioning of genes within the cells lining the airways," says Dr. Ronald Crystal, senior author of the study and chief of the division of pulmonary and critical care medicine at NewYork-Presbyterian/Weill Cornell and chair of the department of at Weill Cornell Medical College in New York City.

Dr. Crystal explains that genes, commonly activated in the cells of heavy smokers, are also turned on or off in those with very low-level exposure.

"The genetic effect is much lower than those who are regular smokers, but this does not mean that there are no health consequences," says Dr. Crystal. "Certain genes within the cells lining the airways are very sensitive to tobacco smoke, and changes in the function of these genes are the first evidence of 'biological disease' in the lungs or individuals."

To make their findings, Dr. Crystal and his collaborators tested 121 people from three different categories: "nonsmokers," "active smokers" and "low exposure smokers." The researchers tested urine levels of nicotine and cotinine -- markers of cigarette within the body -- to determine each participant's category.

The research team then scanned each person's entire genome to determine which genes were either activated or deactivated in cells lining the airways. They found that there was no level of nicotine or cotinine that did not also correlate with genetic abnormalities.

"This means that no level of smoking, or exposure to secondhand smoke, is safe," says Dr. Crystal. He goes on to say that these genetic changes are like a "canary in a coal mine," warning of potential life-threatening disease, "but the canary is chirping for low-level exposure patients, and screaming for active smokers."

Dr. Crystal says that this is further evidence supporting the banning of smoking in public places, where non-smokers, and employees of businesses that allow smoking, are put at risk for future lung disease.

Explore further: New Dominican law OKs abortion if life at risk

Related Stories

Exposure to secondhand smoke in the womb has lifelong impact

Jun 30, 2010

Newborns of non-smoking moms exposed to secondhand smoke during pregnancy have genetic mutations that may affect long-term health, according to a University of Pittsburgh Graduate School of Public Health study published online ...

Secondhand smoke damages lungs, MRIs show

Nov 26, 2007

It’s not a smoking gun, but it’s smoking-related, and it’s there in bright medical images: evidence of microscopic structural damage deep in the lungs, caused by secondhand cigarette smoke. For the first ...

Women more susceptible to harmful effects of smoking

May 18, 2009

Women may be more susceptible to the lung damaging effects of smoking than men, according to new research by Inga-Cecilie Soerheim, M.D., and her colleagues from Channing Laboratory, Brigham and Women's Hospital and University ...

Smokers at risk from their own 'second-hand' smoke

Jan 29, 2010

It is well known that smokers damage their health by directly inhaling cigarette smoke. Now, research published in BioMed Central's open access journal Environmental Health has shown that they are at additional risk from b ...

Recommended for you

The hunt for botanicals

Dec 19, 2014

Herbal medicine can be a double-edged sword and should be more rigorously investigated for both its beneficial and harmful effects, say researchers writing in a special supplement of Science.

Mozambique decriminalises abortion to stem maternal deaths

Dec 19, 2014

Mozambique has passed a law permitting women to terminate unwanted pregnancies under specified conditions, a move hailed by activists in a country where clandestine abortions account for a large number of maternal deaths.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.