The Changing Epidemiology of Type 1 Diabetes: A Global Perspective.

The prevalence of type 1 diabetes is increasing, with significant implications for public health systems worldwide. This review provides a global overview of the current epidemiology of type 1 diabetes, examining the trends, risk factors, and regional variations in incidence. We explore the influence of genetic, environmental, and socio-economic factors on the rising incidence of type 1 diabetes. The review also highlights temporal trends in the management of type 1 diabetes and the risk of mortality and morbidity from acute and long-term complications, including hypoglycaemia, diabetic ketoacidosis, and retinopathy. By synthesizing global and regional data, we aim to provide valuable insights for local health service planning, disease prediction, and tailored interventions. This article underscores the importance of continued research into the epidemiology of type 1 diabetes to better inform prevention, treatment, and management strategies of this growing global health challenge. Plain Language Summary Type 1 diabetes (T1D) is an autoimmune condition that begins silently, with the body attacking insulin-producing cells in the pancreas. This process occurs in two early, silent stages, detectable through blood tests for antibodies, before symptoms appear. It eventually progresses to stage 3, when symptoms develop and insulin treatment becomes necessary. Prevalence T1D affects about 9 million people globally, including over 1.5 million children. In addition to those with symptoms, many children and adults may unknowingly have early stage T1D. These can be detected through screening and are estimated to affect around 0.3% of the population. Incidence In 2024, there were over 500,000 new diagnoses of T1D worldwide, with cases increasing each year. Rates vary by region, age, and sex. Most diagnoses occur in childhood or early adulthood, with a peak around puberty, though it can develop later in life. Rates are highest in high-income countries such as Finland and Australia. Lower rates in other regions may reflect limited surveillance. Some countries have reported fluctuating trends, possibly linked to infections. Improved awareness and diagnostics explain and changing risk factors may also play a role. Risk Factors The risk of T1D is impacted by genetic, demographic, and environmental factors. Family history increases risk, though the majority of people diagnosed don't have a family history. Genetic risk scores can also help identify children at higher risk. Risk changes with age, early signs often appear before age 3, and younger children tend to progress more quickly. Two childhood diagnosis peaks occur at ages 4-7 years and 10-14 years. Researchers are exploring possible subtypes of T1D based on age and disease behaviour. White European populations have the highest rates, but increases are also seen in other groups. Environmental factors like viral infections, caesarean birth, and early diet are being studied. Complications Managing T1D is complex, however poor control can lead to short-term emergencies like hypoglycaemia or diabetic ketoacidosis (DKA), and long-term complications affecting the eyes, kidneys, and nerves. In recent decades, treatment has improved with better insulin regimens and technologies such as insulin pumps, continuous glucose monitors, and hybrid closed-loop systems. These reduce complications and improve quality of life. Yet challenges remain, including high DKA rates at diagnosis-especially in young children and ethnic minorities, and high diabetic retinopathy rates that can impact vision. Early, tight glucose control reduces long-term risks, but people with T1D still face a higher risk of early death. Future Research Directions Major research gaps remain, especially in low- and middle-income countries. Data on early-stage and adult-onset T1D is limited but improving. As new therapies emerge, like teplizumab which is used to delay progression to stage 3, disease patterns may shift. Long-term data from modern technologies is still developing, with linked administrative data offering a promising solution. Conclusion T1D is rising globally and still carries serious health risks. Understanding who is affected, when, and how the disease progresses is essential to improving prevention, care, and outcomes.