Islet cell antibodies in the Japanese population and subjects with type 1 (insulin-dependent) diabetes.

Islet cell antibodies were studied in 1,112 non-diabetic adults, 473 normal school children and 162 Type 1 (insulin-dependent) diabetic patients in a Japanese population. The prevalence of islet cell antibodies was 0.5%, 0.4% and 32%, respectively. Most islet cell antibodies positive subjects with Type 1 diabetes had short duration of the disease. No patients who had over 10 years from the onset had islet cell antibodies. Six non-diabetic adults with islet cell antibodies were followed for 4 years. Only one with Hashimoto's thyroiditis showed a diabetic pattern in her oral glucose tolerance test. However, none developed overt insulin-dependent diabetes until 1984. Two out of these six subjects continued to be positive for both islet cell antibodies and antithyroid antibodies or antinuclear antibodies. Islet cell antibodies in the remaining four patients disappeared during the second year. It is difficult to predict the onset of Type 1 diabetes by islet cell antibodies in non-diabetic individuals because they may be transient.