Screening for Type 1 Diabetes in Adults: What Needs to Change

Contrary to longstanding beliefs, over half of all new type 1 diabetes (T1D) cases occur in adult patients, with different genetic, immune, and metabolic conditions than childhood T1D.¹

In an interview with HCPLive, Justin Gregory, MD, MPH, the field medical director for autoimmune T1D at Sanofi and a pediatric endocrinologist, and Steve Zortman, MPH, RN, the program manager of the Diabetes Education and Management Program at UVA Health, discussed the importance of frequent and in-depth screening and early recognition of T1D in adults.

“A real advantage of early detection is the opportunity for what I call the soft landing,” Gregory told HCPLive. “In other words, contrast; you’ve been diagnosed in the hospital, you have multiple IVs in your body, and it’s such a horrible anxiety-provoking event. Contrast that with detecting it early, gradually easing you into living with type 1 diabetes in the sense that you’re doing more monitoring and more insulin therapy. Which would you prefer to have?”

The American Diabetes Association (ADA) Standards of Care in Diabetes 2025 highlight the critical importance of screening patients early and often for both biological and social determinants of metabolic health. The sooner T1D is caught in patients, the more time those patients have to adapt to regular monitoring and regulating of symptoms – waiting too long, on the other hand, naturally invites the risk of diabetic ketoacidosis or other complications.²

Recent data have shown that adult-onset T1D may be more common than childhood-onset T1D, with some studies reporting similar incidence between individuals aged 0-19 years and those aged 40-100 years. Despite this, clinical practice and training have long focused on T1D as a childhood disease, often mistakenly categorizing adults as having type 2 diabetes (T2D) instead.¹

Adults with T1D are also at an increased risk of other autoimmune conditions, with roughly 30% of patients also presenting with thyroid autoimmunity, and those with multiple islet autoantibodies are at an increased risk of progression to hypothyroidism. Additionally, adult patients are often diagnosed with C-peptide decline more frequently than children, attributed in part to a higher average body mass index (BMI).¹

The ADA’s guidelines primarily recommend HbA1c and fasting plasma glucose, among other methods, in screening for T1D, as well as detecting prediabetes. They also point out the fact that diabetes can manifest at any point along the spectrum of clinical presentations, from patients who appear low-risk to those with established symptoms. The document reemphasizes the need for early, frequent, and routine screening to protect these underrepresented adults with T1D.²

Ultimately, Gregory and Zortman discuss the value of being conscious of the differences in presentation between autoimmune diabetes and typical T2D to avoid misdiagnosis and to provide optimal care for patients of all ages.

“Let’s imagine that you’re a family health doctor or a family practice doctor who mostly sees adults. You see so much type 2 that pattern recognition sets in,” Gregory said. “Let’s say you’ve already seen 9 patients who you’ve identified as having type 2 diabetes or prediabetes – pretty soon, everything starts to look like type 2 diabetes.”

Editors’ Note: Gregory reports disclosures with Sanofi, Medtronic, vTv Therapeutics, Beckman Coulter Inc., and DRI Capital, Inc. Zortman reports no relevant disclosures.

References

1. Leslie RD, Evans-Molina C, Freund-Brown J, et al. Adult-Onset Type 1 Diabetes: Current Understanding and Challenges. Diabetes Care. 2021;44(11):2449-2456. doi:10.2337/dc21-0770

2. American Diabetes Association Professional Practice Committee; 1. Improving Care and Promoting Health in Populations: Standards of Care in Diabetes—2025. Diabetes Care 1 January 2025; 48 (Supplement_1): S14–S26. https://doi.org/10.2337/dc25-S001