Type 1 Diabetes and NIH Women's Health Research

Signs, Symptoms, and Risk Factors

Type 1 diabetes, sometimes called insulin-dependent or juvenile diabetes, is a chronic autoimmune condition in which the immune system destroys insulin-producing cells in the pancreas, leaving the body with little or no insulin.¹ Without enough insulin, glucose accumulates in the bloodstream, causing excessive thirst, frequent urination, hunger, weight loss, and fatigue.^{1 , 2} Type 1 diabetes most often begins in childhood or young adulthood but can appear at any age. Left unchecked, high blood glucose can cause serious long-term complications that affect the eyes, kidneys, nerves, and heart.^{1 , 2} It can also trigger diabetic ketoacidosis, a life-threatening emergency in which the blood becomes dangerously acidic.

Type 1 diabetes develops from a mix of genetic susceptibility and immune system dysfunction.¹ Environmental factors, such as air pollutants and viral infections, may trigger the immune system to attack insulin-producing cells in people who are genetically at risk.³ Having a parent or sibling with type 1 diabetes raises the risk of developing the disease, but a family history is not required.⁴ Certain immune-related genes, particularly in the human leukocyte antigen region, increase disease risk, and diabetes-related autoantibodies often appear before symptoms begin.^{3 , 5}

Impact on Women’s Health

Unlike many autoimmune conditions, which occur more often in women, the rates of type 1 diabetes are relatively comparable between the sexes before puberty, and a male predominance emerges after puberty in many higher-incidence populations.^{6 , 7} However, women with type 1 diabetes face unique health challenges that can change across their lifespan. Women with type 1 diabetes are more prone to urinary tract and vaginal infections, depression, and a higher risk of cardiovascular disease than those without the disease.⁸ Careful blood glucose control before and during pregnancy is important, as high glucose levels increase the risk of birth defects and other complications.⁹ Insulin needs change considerably across the trimesters, and continuous glucose monitoring, often paired with automated insulin delivery systems, is now recommended to help women stay within range.^{10 , 11} After menopause, lower estrogen levels can make glucose control more difficult and may increase cardiometabolic and bone health risks.¹²

Diagnosis and Treatment

Diagnosis of type 1 diabetes relies on tests that measure glucose levels, such as fasting or random blood glucose, along with the A1C test, which reflects average blood glucose levels over the past few months.^{1 , 2} Antibody testing is then used to confirm the cause is autoimmune. Treatment requires lifelong insulin therapy through injections or insulin pumps, regular glucose monitoring, and education to support daily self-management. Newer technologies that link continuous glucose monitoring devices with insulin pumps are helping improve glucose control and reduce the frequency of episodes of low blood sugar.¹³ Teplizumab, a recently approved disease-modifying therapy, can delay the onset of clinical type 1 diabetes in people who show early signs of the autoimmune process.^{5 , 14}

Ongoing Research

Research is exploring whether earlier treatment with teplizumab could prevent or further delay the development of type 1 diabetes.¹⁴ Female relatives of individuals with type 1 diabetes can be screened for the autoantibodies that mark early stage disease to identify candidates for preventive therapy.

NIH-supported research has helped shape current care for type 1 diabetes. Through the Special Statutory Funding Program for Type 1 Diabetes Research, NIH supports studies to prevent, treat, and ultimately cure type 1 diabetes, including major research networks, such as TrialNet.^{13 , 15} Landmark studies funded by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) demonstrated that tighter blood glucose control reduces long-term complications, an important finding for women, whose hormone changes can influence glucose levels over time.¹⁶ The recently completed Estrogen in Diabetes study also found that estrogen, which is normally protective for blood vessels in women, may instead contribute to blood vessel dysfunction in premenopausal women with type 1 diabetes.^{17 , 18}