Lung function tests do not always diagnose lung disease

We all know smoking is not good for us.   In fact, it causes damage to nearly every organ in the human body.  A recent study came out from the National Jewish Health, a hospital in Denver, Colorado, which found that many long-term smokers, passed a known test which should detect signs of lung disease, even though they actually had lung disease. The flaw in the widely used lung-function tests may be leaving millions undiagnosed. One of the study’s senior author James D. Crapo found that you cannot use a lung-function test alone to test for lung disease.  He found that many smokers who had lung-function tests fall within population norms have lung disease.
The research team examined 8,872 people between the ages of 45 to 80, who smoked a pack a day for 10 to 50 years. Half of the group passed a lung-function test, which measures how much air you can take into and blow out of your lungs, and how fast you can do it by blowing into a spirometer. According to the National Heart, Lung, and Blood Institute, the test is designed to diagnose asthma, scarring of the lung, and chronic obstructive pulmonary disease (COPD).
When the group that passed the lung-function test was reevaluated based on CT scans, patients’ physical abilities, use of respiratory medication, and respiratory symptoms, 55 percent actually had respiratory problems. Researchers believe it’s likely that many of those patients have early-stage COPD. The disease causes inflammation and thickening of the airways, making it the third leading cause of death in the United States.
Early detection of COPD leads to an earlier treatment intervention, ultimately lessening symptoms, slowing the progression, and improving overall quality of life. By demonstrating the lung-function test’s failure, the researchers hope to prove screening with CT scans should be routine in order to detect early stages of lung cancer and COPD.
On the CT scans alone, researchers were able to see airway thickening or emphysema in 42 percent of the undiagnosed participants. Twenty-three percent had a significant shortness of breath, and 15 percent not could walk 350 meters in six minutes, compared to the four percent of those who never smoked. Undiagnosed participants also had a considerably worse quality of life than those who had never smoked.
Source: Regan E and Crapo JD. JAMA Internal Medicine. 2015

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