ESPE Yearbook of Paediatric Endocrinology

Brief summary: The authors developed a model to estimate the worldwide prevalence of Type 1 diabetes (T1D) in 2040. Compared to 2021, when an estimated 8.4 million individuals had T1D (including 18% < 20 years), the prevalent cases are expected to increase to 13.5–17.4 million in 2040, with the largest relative increase taking place in low- and middle-income countries.

This model, using published data (available from only 97 countries worldwide) provides a global projection of T1D prevalence, incidence and mortality that will serve as a bedrock for later updates as more information becomes available. Besides the projection that the number of patients with T1D will increase by 60–107% in 2040 compared to 2021, the data highlight several important points that all call for better education, better epidemiological data, better understanding of the differences in pathophysiology of T1D between ethnic groups and, potentially, different management approaches in particular in low- and middle-income countries. First, the contrast in remaining life expectancy for 10-year-old children diagnosed with T1D in 2021 between different socio-economic contexts is shocking. In low-income countries, the remaining life expectancy is estimated to be only 13 years, contrasting with 61 years in high-income countries. Second, 47% of the estimated 175 000 deaths due to T1D worldwide in 2021 took place in Sub Saharan Africa and in South Asia. Non diagnosis (estimated in people aged <25 years only) was also the cause of death in a majority (66%) of patients in Sub Saharan Africa and in South Asia.

Finally, separate assumptions were made for Africa, reflecting the fact that the peak age of T1D occurs later in this region, for reasons that remain poorly understood. Specifically, the genetic susceptibility of patients in Sub Saharan Africa and the relative contribution of HLA genes and of other genetic and non-genetic factors are unclear. Indeed, the lower rate of positivity for the islet antibodies traditionally used to confirm an autoimmunity origin of T1D suggest that autoimmunity may not explain all cases of T1D in Sub Saharan Africa and raises the possibility that different therapeutic approaches need to be developed (1).

Reference: 1. Katte JC, McDonald TJ, Sobngwi E, Jones AG. The phenotype of type 1 diabetes in sub-Saharan Africa. Front. Public Health 2023; 11:1014626. DOI: 10.3389/fpubh.2023.1014626.