Narrator: This is Science Today. Each year, pulmonary fibrosis causes more than five thousand Americans to die of suffocation. This happens after progressive scarring and inflammation in the lungs prevent oxygen from getting into the bloodstream. Dr. Dean Sheppard, of the University of California, San Francisco says pulmonary fibrosis affects over one hundred thousand people nationwide.
Sheppard: It's actually not really one disease - it's the end effect of a number of different diseases, so actually there are probably over a hundred different individual causes of pulmonary fibrosis.
Narrator: One of the more common causes is a disease called sarcoidosis, which is of unknown origin, but usually targets the lungs.
Sheppard: There are also people who have what are called rheumatologic diseases - one's called lupus, another's called scleroderma, rheumatoid arthritis sometimes can lead to pulmonary fibrosis and then one of the largest categories is something we call idiopathic pulmonary fibrosis, which means we don't know what causes it.
Narrator: For Science Today, I'm Larissa Branin.