Insulin autoimmune syndrome is the third leading cause of spontaneous hypoglycemic attacks in Japan.

From 1979 to 1981, questionnaires were sent to 2094 hospitals throughout Japan to investigate the causes of severe hypoglycemic attacks other than the administration of oral hypoglycemic agents or insulin preparations. The survey revealed three main causes for the attacks, of which the first was insulinoma, the second extrapancreatic neoplasms, and the third was insulin autoimmune syndrome (IAS), in descending order. Seven years later, a second survey was carried out, which showed the order of the three disorders as the cause of the hypoglycemic attacks to be the same as in the first survey. In both studies it was suggested that the IAS was frequently induced by thiol compounds.