People commonly know that second-hand smoke creates problems for those with breathing difficulties, such as cystic fibrosis. Now, for the first time, researchers says they have genetic evidence that explains why. VOA's Carol Pearson reports.
"I'm very lucky. I've been very lucky," says cystic fibrosis patient Anne Governor.
Cystic fibrosis is an inherited disease that clogs the lungs and pancreas with sticky mucus, making breathing and digestion difficult.
Antibiotics help prevent lung infections, and breathing machines can help loosen mucus, but there is no cure.
Stacy Danko also has cystic fibrosis. She has always wondered why she has made it past her 40th birthday, while her sister -- who also had the disease -- died at the age of 12. She recalls, "My sister was just so sick from the day that she was born. She just had such a different disease than I have."
Dr. Garry Cutting and other researchers at Johns Hopkins University School of Medicine may have found the answer to Danko's question. "What we really wanted to know is what makes one patient or helps one patient do better than another," he said.
Dr. Cutting found that exposure to second-hand smoke in the womb or in the household damaged the lungs of all patients with cystic fibrosis. But he also found a slight mutation in a different gene accelerates the disease.
Both Stacy Danko and her sister were exposed to second-hand smoke as children, and Stacy would like to know if she has the mutated gene. "If you know you carry the gene that is going to make it affect you more, then you are going to be that much more careful."
Patients in the Johns Hopkins study that had the mutated gene and cystic fibrosis reacted more strongly to second-hand smoke than their brothers or sisters. The damage to their lungs from second-hand smoke doubled.
"For the first time, we now see that other genes play a role in how bad that effect is on the lungs of CF [cystic fibrosis] patients," Dr. Cutting said.
The researchers chose people with cystic fibrosis because they say it is easier to study the impact of environmental changes in them than in the general population. They believe their work may also apply to people with asthma and other respiratory problems. The study was published in the Journal of the American Medical Association.
Some video courtesy of The Journal of the American Medical Association