Type 1 Diabetes
Type 1 diabetes is a chronic health condition in which the body’s own immune system attacks and kills the cells in the pancreas that produce insulin. Insulin is needed to convert sugar (also called glucose) from food into energy for the body’s cells. Without insulin, the body cannot manage blood sugar, and people can experience dangerously high blood sugar levels (called hyperglycemia). To manage blood sugar levels, people with type 1 diabetes must take insulin injections or receive insulin through a pump. Read our resource page to learn more about the symptoms, complications, and various treatment options for type diabetes.
There is currently no way to prevent type 1 diabetes, though research has made significant strides in recent years. Unfortunately, the genetic and environmental triggers for the immune attack are not well understood, and 80% of people with the condition do not have a family history of type 1 diabetes.
People who have family members with type 1 diabetes are more likely to develop it themselves. If an immediate relative (parent, sibling, or child) has type 1 diabetes, your risk of developing the condition is much greater than the risk of the general population (normally a 1% risk). Depending on whether a father or mother has type 1 diabetes, and when they developed the condition, the chance of a child having type 1 diabetes can range from 1% to 12%, or 10% to 25% if both parents have diabetes.
If someone in your family has type 1 diabetes, talk with your healthcare team about screening for the other family members. Discovering diabetes early on is an effective way to reduce the chances of dangerous health complications.
Common symptoms of type 1 diabetes include:
Feeling very thirsty
Feeling very hungry, even though you are eating
Cuts or bruises that are slow to heal
Weight loss, even though you are eating more
Type 1 diabetes can be diagnosed through any of the following tests:
An A1C test, formally called a glycated hemoglobin test or HbA1C test. This blood test gives an estimate of a person’s average blood sugar levels from the past two or three months. An A1C of 6.5% or higher is considered diabetes (5.7% to 6.4% is considered prediabetes, and an A1C below 5.7% is considered normal.)
A fasting plasma glucose (FPG) test measures a person’s blood glucose level after a period of fasting (not eating) for eight hours. An FPG of 126 mg/dl or higher indicates diabetes.
An oral glucose tolerance test (OGTT) measures the body's blood glucose level two hours after consuming a sugary drink. An OGTT result of 200 mg/dl or higher at two hours indicates diabetes.
In someone with symptoms of high blood sugar (or hyperglycemia), a random plasma glucose test can be used to check blood sugar levels. A blood sugar level above 200 mg/dl indicates diabetes.
Your healthcare professional may also suggest a diabetes-related antibody test to specifically confirm a diagnosis of type 1 diabetes.
People with type 1 diabetes must take insulin daily to help manage their blood sugar levels. There are two main types of insulin: basal insulin and prandial (mealtime) insulin. Basal insulin is taken once or twice per day to provide a constant, low level of insulin action – it helps keep blood sugars at a consistent level when you are not eating, but it can’t cover glucose spikes after mealtime. Prandial insulin, on the other hand, is taken before meals and acts rapidly in the body, stabilizing blood sugar levels after eating. Some people with type 1 diabetes also take other medications to support diabetes management. For an overview of diabetes drugs available today, please see our diabetes drugs resource page.
In 2017, about 31% of adults with type 1 diabetes in the US used continuous glucose monitors (CGM), and this number has been increasing dramatically – in 2021, the T1D Exchange reported that more than 80% of their participants are using CGM. CGM devices track glucose levels every few minutes throughout the day and night, providing extremely helpful information for staying in your target blood glucose range. Unfortunately, CGMs can be expensive and may not be covered under some insurance plans; CGMs are currently reimbursed through Medicare for people with type 1 diabetes.
Hypoglycemia refers to low blood sugar levels. A blood sugar level below 70 mg/dl (3.9 mmol/l) is typically considered hypoglycemia, and you may experience a host of symptoms when your blood sugar dips this low.
Symptoms of hypoglycemia include confusion, headache, irritability, trouble concentrating, fatigue, hunger, sweating, shaking, and fast heartbeat. Symptoms of severe hypoglycemia include combativeness, disorientation, seizures, difficulty speaking, loss of consciousness, or a coma.
To raise blood sugar levels, people commonly eat a specific amount of fast-acting carbohydrates. In severe cases, emergency glucagon can be used.
Hyperglycemia refers to high blood sugar levels. A blood glucose level of 180 mg/dl (10 mmol/l) or higher is considered hyperglycemia and can result in acute symptoms and if persistent, eventually lead to long-term complications. To bring blood glucose levels back down, people commonly take a "correction dose" of rapid-acting insulin.
Symptoms of hyperglycemia include confusion, headache, frequent and excessive urination, extreme thirst, blurry vision, weakness, shortness of breath, and nausea.
Diabetic ketoacidosis (DKA) is an emergency that can occur when someone is experiencing hyperglycemia. Without enough insulin to help cells take up glucose from the blood, the body burns fatty acids for energy, and the blood becomes acidic. Symptoms of DKA include dehydration, shortness of breath, fruity-smelling breath, nausea and vomiting, confusion, or loss of consciousness. If someone with type 1 diabetes is showing signs of DKA, that person should measure glucose and ketones levels and seek medical attention immediately.
Having type 1 diabetes increases a person’s risk of developing long-term health complications. Over time, the high blood sugar levels that are associated with diabetes can damage the body, affecting the nervous system, blood vessels, eyes, heart, and kidneys. Careful management, and maintaining stable blood glucose levels, can reduce a person’s risk for complications. To read more about complications, click here.
Because people with type 1 diabetes often develop the condition at a young age, many decades of high blood sugar levels challenge the body. While research is sparse, a 2020 study revealed that type 1 diabetes may reduce life expectancy by about eight years. However, as more people gain access to appropriate treatment with improved diabetes therapy and technology, life expectancy for people with type 1 diabetes is approaching that of the general population.
*Please note, this page is not a comprehensive list of all the available resources.