MIAMI--(BUSINESS WIRE)--A single gene nearly tripled the loss of lung function in some firefighters and paramedics exposed to the intense air pollution following terrorist attacks that leveled the World Trade Center a decade ago, researchers have found.
The gene for Alpha-1 Antitrypsin Deficiency (Alpha-1) led to severe loss of lung function that continued year after year, much longer than health effects reported in other studies of so-called “First Responders”.
In previous studies of about 12,000 firefighters and paramedics who were at the WTC site in the two weeks after 9/11, the Fire Department of New York found:
- Firefighters lost lung function in the first year more than 12 times faster than normal. Paramedics lost lung function at more than 10 times the normal rate.
- They never recovered that lung function.
- For most, after the first year, the lung function loss slowed to normal. (Everyone loses a small amount of lung function as they age.)
But one study by the Fire Department of New York raised a different question. What happened to those who had a risk factor for airway disease – specifically an Alpha-1 gene that lowers levels of a protective protein in the blood and lungs?
The study found:
- Those who were “mildly deficient” in levels of Alpha-1 protein – they had the “S” gene – continued to lose lung function at double the normal rate through the entire four years of the study.
- Those who were “moderately deficient” in Alpha-1 protein – they had a single “Z” gene – lost lung function at triple the normal rate.
- This accelerated loss of lung function continued through the duration of the study – even though none of the firefighters or paramedics tested was severely deficient (with two “Z” genes).
David Prezant, MD, Chief Medical Officer of the New York Fire Department, was the principal investigator for the study reported in the medical journal CHEST. Prezant said this study shows “a novel gene-by-environment interaction” – an association between even mild or moderate Alpha-1 and loss of lung function from an environmental disaster.
Adam Wanner, MD, scientific director of the Alpha-1 Foundation, said that doctors and researchers have known for many years that “low-dose environmental stress, such as cigarette smoking, and a high genetic predisposition to lung disease such as Alpha-1 (ZZ), very often leads to lung disease.”
But Wanner says the 9/11 study gave us a further lesson.
“The 9/11 experience suggests that a high dose of an environmental irritant can diminish lung function in individuals with a low genetic predisposition for lung disease, supporting the notion that environment-gene interaction can be expressed as an equation: Environmental stress x genetic predisposition = severity of lung disease."
A DIFFERENT KIND OF FIRE
Several studies done before 9/11 showed that firefighters often develop respiratory irritation and loss of lung function immediately after working to put out a major fire. But these studies found that the lung function losses were temporary. The World Trade Center disaster was much worse, “exposing thousands of persons to a dense, persistent dust cloud of pulverized building materials and chemical by-products of combustion,” according to researchers.
Prezant said in an interview with the New York Times, “This was not a regular fire. There were thousands of gallons of burning jet fuel and an immense, dense particulate matter cloud that enveloped these workers for days. It caused acute inflammation of the airways and the lungs. That inflammatory impact has been persistent.”
Prezant said firefighters or paramedics with a single Alpha-1 gene consistently reported more symptoms than most, such as coughing, wheezing, sore throat, shortness of breath and nasal drip or congestion. These differences remained four years after 9/11.
About Alpha-1 Antitrypsin Deficiency:
Alpha-1 Antitrypsin Deficiency (Alpha-1) is the most common known genetic risk factor for emphysema. For this reason, it is sometimes referred to as “genetic COPD.” There are about 100,000 people with Alpha-1 (ZZ) in the United States. Fewer than 10% of them have been correctly diagnosed. The cause of Alpha-1 is inherited gene defects. For a person to have a severe form, you must have inherited two copies of the defective gene, one from each parent. People with one normal and one defective gene (for example, MZ) are called “carriers”. An estimated 20 million people in the United States are carriers. Alpha-1 can cause both lung and liver disease; lung disease is the most common. Alpha-1 can be detected by a simple blood test.
About the Alpha-1 Foundation:
The mission of the Alpha-1 Foundation is to provide the leadership and resources that will result in increased research, improved health, worldwide detection, and a cure for Alpha-1 Antitrypsin Deficiency. For information, visit www.alpha-1foundation.org.