Patterson CC, et al. - In this article, researchers sought to describe the methods, results, and limitations of the International Diabetes Federation (IDF) Diabetes Atlas 9th edition estimates of worldwide numbers of cases of type 1 diabetes in children and adolescents. In the published literature, incidence rates derived from registers of newly-diagnosed cases were mostly reported. For 45% of countries, incidence rates (ranging from 6% in the sub-Saharan Africa region to 77% in the European region) were available. The under 15 year (under 20 year) age-groups exhibited worldwide annual incidence of 98,200 (128,900) new cases. Corresponding prevalence estimates were 600,900 (1,110,100) existing cases. Most IDF regions showed an increase in numbers compared with estimates in earlier Atlas editions. This indicates increases in incidence rate, but decreases in prevalence estimates in sub-Saharan Africa were noted because allowance has been made for heightened mortality in those with diabetes. Findings thereby suggest a continuous increase in Worldwide estimates of numbers of children and adolescents with type 1 diabetes.