Number of T1D Cases Expected to Double Worldwide by 2040

Approximately 8.4 million people around the world lived with type 1 diabetes (T1D) in 2021, and this number is predicted to rise to 17.4 million by 2040, according to a modelling study published in The Lancet Diabetes & Endocrinology.

The study was conducted by researchers from the United States, Canada, Australia, and Luxembourg. These researchers also estimated around 3.1 million individuals with T1D would have been alive in 2021 if they had not died prematurely as a direct result of poor T1D care, and that an additional 700,000 individuals would still be alive if they had not died due to a lack of diagnosis.

As reported by BMJ, these findings have been entered into an open source database for the T1D Index Project, which was launched by the non-profit Juvenile Diabetes Research Foundation (JDRF) this month and shows how many people live with T1D around the world and what actions can be made to reduce its effects. The study was funded by JDRF.

The researchers set a discrete-time illness-death model (Markov model) to data on T1D incidence and associated mortality to estimate T1D incidence, prevalence, association mortality, and life expectancy in 201 countries.

Incidence and mortality data were available from 97 and 37 countries, respectively, and data from an expert survey were used to estimate T1D diagnosis rates. Random-forest regression of published T1D mortality data was used to model estimated mortality, and life expectancy was calculated using life tables.

These estimates were validated against observed prevalence data from 15 countries.

The authors found between 8.1 and 8.8 million people lived with T1D globally in 2021.

Of this group, 1.5 million (18%) were aged younger than 20 years, 5.4 million (64%) were aged between 20 and 59 years, and 1.6 million (19%) were aged 60 and older.

“There is a systemic trend towards other published estimates having lower paediatric prevalence and higher adult prevalence than in our model,” the authors noted.

In 2021, half a million new cases of T1D were diagnosed, with a median age of onset of 39 years. Further, roughly 35,000 individuals who did not receive a T1D diagnosis died within 12 months of symptom onset.

“The burden of type 1 diabetes in 2021 is vast and is expected to increase rapidly, especially in resource-limited countries,” the authors said, noting 1.8 million, or one-fifth, of individuals living with T1D globally in 2021 lived in low-income or lower–middle-income countries.

Additionally, the mean remaining life expectancy for a 10-year-old diagnosed with T1D in 2021 ranged from 13 years in low-income countries to 65 years in high-income countries.

In 2040, researchers predict between 13.5 and 17.4 million prevalent type 1 diabetes (T1D) cases, reflecting a 60% to 107% increase in global cases compared with 2021.

The researchers also estimated 3.7 million missing prevalent cases of T1D in 2021.

“The substantial missing prevalence highlights the premature mortality of type 1 diabetes and an opportunity to save and extend lives of people with type 1 diabetes,” the authors said. “Our new model, which will be made publicly available as the Type 1 Diabetes Index model, will be an important tool to support health delivery, advocacy, and funding decisions for type 1 diabetes.”

Reference

Gregory GA, Robinson TIG, Linklater SE, et al. Global incidence, prevalence, and mortality of type 1 diabetes in 2021 with projection to 2040: a modelling study. Lancet Diabetes Endocrinol. 2022;S2213-8587(22)00218-2. doi:10.1016/S2213-8587(22)00218-2