A REVIEW OF THE RECENT EPIDEMIOLOGIC DATA ON THE WORLDWIDE INCIDENCE OF TYPE-1 (INSULIN-DEPENDENT) DIABETES-MELLITUS

Nearly 70 registries from more than 40 countries have collected and pu blished incidence data of childhood Type 1 (insulin-dependent) diabete s mellitus up to the end of the 1980s. The majority of incidence data comes from regions of high incidence i. e. from Europe and North Ameri ca. All these published data facilitate the descriptive comparison of incidence and variation of the occurrence of Type 1 diabetes roughly t hroughout the northern hemisphere. The aim of this paper is to review and compare the most recent epidemiology data on the incidence of Type 1 diabetes among children under the age of 15 years. A clear differen ce in incidence appeared between northern and southern hemisphere with no countries below the equator having an incidence-greater than 15.0 per 100,000. In contrast above the equator the disease is common. Betw een continents the variation in incidence showed that the lowest incid ences were found in Asia, followed by Oceania (Australia and New Zeala nd), South and North America, and the highest rates were in Europe. Th e incidence varied from 0.6 per 100,000 in Korea and Mexico to 35.3 pe r 100,000 in Finland showing prominent worldwide variation in incidenc e of Type 1 diabetes. The largest intracontinental variation in incide nce appeared in Europe, varying from the highest in Finland to the low est (4.6 per 100,000) in northern Greece. The highest incidence in the world was in northern Europe, but within the continent scale there we re some striking exceptions from the overall level of incidence. In Ic eland, the northern-most island nation in Europe, the incidence is onl y one-half of that in Norway and Sweden and one-third of that in Finla nd. In contrast, in Sardinia in southern Europe the Type 1 diabetes in cidence is virtually the same as in Finland, three times higher than o verall incidence in Europe. Large variation was also seen in small ''p ockets'' of countries, particularly in the Baltic sea region. The worl dwide variation in incidence reflects the distribution of ethnic popul ations and demonstrates the importance of the differential genetic sus ceptibility between populations.