Rheumatoid arthritis is a disease of unknown cause. It has a slight tendency to be familial; the sex ratio in peripheral rheumatoid arthritis is 3 women to 1 man, and 80% of the cases occur between the ages of 25 to 50, with the peak at 35 to 40. No indexes of abnormal function of the pituitary or adrenal glands can be detected by current methods. Rheumatoid arthritis is variously claimed to be (1) an infectious disease, (2) a metabolic disease, (3) a disease with an endocrinologic basis, (4) a disease of the peripheral circulatory apparatus, (5) a disease of the nervous system, (6) a psychogenic disease, and (7) a disease of hypersensitivity. Such a list indicates how little actually is known about the cause of this disease.
Rheumatoid arthritis is invariably described as a systemic disorder. Scudamore, as early as 1827, pointed out that the
Committee of the American Rheumatism Association. PRIMER ON THE RHEUMATIC DISEASES. JAMA. 1953;152(5):405-414. doi:10.1001/jama.1953.63690050007009