It affects people over 50 years old. This hyperviscosity interferes with blood flow through small blood vessels and causes many of the symptoms of the disease.
Risk factors are unknown.
The incidence is 5 out of 100,000 people. The cause is unknown, therefore prevention is unknown. A CBC shows low red blood cell count and platelet count . This may be seen as a serum immunoelectrophoresis that shows an IgM spike or a serum immunofixation that shows an IgM spike. Bone lesions are very rare.