STOCKHOLM, Sweden, Sept. 23, 2022 — The number of people living with type 1 diabetes worldwide is expected to double by 2040, with most of the new cases among adults living in low- and middle-income countries, new modelling data suggests.

The forecast, developed from available data collected in the new Type 1 Diabetes Index, provides estimates for type 1 diabetes rates, associated mortality, and life expectancy for 201 countries for the year 2021.

"The worldwide prevalence of type 1 diabetes is substantial and growing. Improved surveillance — particularly in adults who make up most of the population living with type 1 diabetes — is essential to enable improvements to care and outcomes,” the authors wrote. “There is an opportunity to save millions of lives in the coming decades by raising the standard of care (including ensuring universal access to insulin and other essential supplies) and increasing awareness of the signs and symptoms of type 1 diabetes to enable a 100% rate of diagnosis in all countries.

One in Five of All Deaths From Type 1 Diabetes is in the Under 25s

The new findings were published in the journal Lancet Diabetes & Endocrinology. The T1D Index Project database was published Sept.

According to the model, about 8.4 million people were living with type 1 diabetes in 2021 with one fifth from low- and middle-income countries. An additional 3.7 million died prematurely and would have been added to that count had they lived. The estimate is that about one in five of those who died because of type 1 diabetes in 2021 were younger than 25 years and had undiagnosed diabetes.

"It is unacceptable that, in 2022, some 35,000 people worldwide are dying undiagnosed within a year of onset of symptoms. There also continues to be a huge disparity in life expectancy for people with type 1 diabetes, hitting those in the poorest countries hardest," said Chantal Mathieu, MD, , senior vice-president of the European Association for the Study of Diabetes and an endocrinologist based in Belgium.

By 2040, the model predicts that between 13.5 and 17.4 million people will be living with the condition, with the largest relative increase from 2021 in low-income and lower-middle-income countries. A majority of both incident and prevalent cases of type 1 diabetes are adults, with an estimated 62% of 510,000 new diagnoses worldwide in 2021 occurring in people aged 20 years and older.