Pulmonary sarcoidosis can cause loss of lung volume and increased lung stiffness. The cause of sarcoidosis remains a mystery. It has been suggested that an exaggerated defense reaction against some event or substance perceived as a threat by the immune system may trigger the condition and that there may be contributing genetic factors. The Swedish study followed 474 patients from 1966 to 1980 and followed 8,541 patients from 1964 to 1994. Thereafter, the risk for lung cancer was significantly decreased, while the risk for non-Hodgkin's lymphoma was the same in patients with and without sarcoidosis.
Spontaneous remissions occur in nearly two-thirds of sarcoidosis patients.
Despite the often favorable prognosis in sarcoidosis, the new study indicates that these patients deserve increased medical attention, the researchers write in the November issue of the American Journal of Respiratory and Critical Care Medicine7, published by the American Lung Association. They also note that although the underlying mechanism is unclear, chronic inflammation in sarcoidosis may be involved in the increased risk of cancer. Occurrence of sarcoidosis among African-Americans is more than three times that among whites. It is also more common in whites of northern European descent than in other whites. Swedes, Danes and U.S. blacks have the highest prevalence rates in the world.