MEDICAL EDUCATION

Type 1 diabetes

Whether you have type 1 diabetes, are a caregiver or loved one of a person with type 1 diabetes, or just want to learn more, the following page provides an overview of type 1 diabetes.

New to type 1 diabetes? Check out "Starting Point: Type 1 Diabetes Basics," which answers some of the basic questions about type 1 diabetes: what is type 1 diabetes, what are its symptoms, how is it treated, and many more!

Want to learn a bit more? See our “Helpful Links” page below, which provides links to diaTribe articles focused on type 1 diabetes. These pages provide helpful tips for living with type 1 diabetes, our patient-perspective column by Adam Brown, drug and device overviews, information about diabetes complications, and some extra pages we hope you’ll find useful!

Starting Point: Type 1 Diabetes Basics

• What is type 1 diabetes?
• Can type 1 diabetes be prevented?
• What is the risk of developing type 1 diabetes if it runs in my family?
• What are its symptoms?
• How is it diagnosed?
• How is it treated?
• Do all people with type 1 diabetes wear pumps? 
• How many people with type 1 diabetes use continuous glucose monitors?
• What is hypoglycemia?
• What is hyperglycemia?
• What are the complications of type 1 diabetes?
• Does type 1 diabetes affect life expectancy?

What is Type 1 Diabetes? Type 1 diabetes is disease in which the body can no longer produce insulin. Insulin is normally needed to convert sugar (also called glucose) and other food sources into energy for the body’s cells. It is believed that in people with type 1 diabetes, the body’s own immune system attacks and kills the beta cells in the pancreas that produce insulin. Without insulin, the body cannot control blood sugar, and people can suffer from dangerously high blood sugar levels (called hyperglycemia). To control their blood glucose levels, people with type 1 diabetes take insulin injections. Before the discovery of insulin, type 1 diabetes was a death sentence (and it still is for patients with poor access to insulin).

Can Type 1 Diabetes Be Prevented? Unfortunately, the genetic and environmental triggers for the immune attack that causes type 1 diabetes are not well understood, although we know that family members of people with type 1 diabetes are at more risk. There is currently no known way to prevent type 1 diabetes, although Diabetes TrialNet runs studies testing various treatments that could potentially prevent or slow progression of the disease.

What is the Risk of Developing Type 1 Diabetes if it Runs in My Family? People who have family members with type 1 diabetes are more likely to develop it themselves. According to the Joslin Diabetes Center, if an immediate relative (parent, brother, sister, son or daughter) has type 1 diabetes, your risk of developing type 1 diabetes is about 10 to 20 times the risk of the general population (normally a 1% risk). If one child in a family has type 1 diabetes, their siblings have about a 1 in 10 risk of developing it by age 50. Interestingly, a child from a father with type 1 diabetes has about a 10% chance of developing it, while a child with a mother with type 1 diabetes has about a 4% risk of developing it if the mother was 25 or younger at birth, and a 1% risk of developing it if the mother was older than 25 at birth (consistent with the general population risk).

What are its Symptoms? According to the American Diabetes Association, the common symptoms of type 1 diabetes are:

• Urinating often
• Feeling very thirsty
• Feeling very hungry even though you are eating
• Extreme fatigue
• Blurry vision
• Cuts/bruises that are slow to heal
• Weight loss even though you are eating more

How is it Diagnosed? 

According to the ADA, diabetes can be diagnosed through any one of the following tests:

1. A glycated hemoglobin test, which is commonly referred to as an HbA1c, or simply A1c, test. This test measures the body’s average blood sugar levels from the past 3 months. An A1c of 6.5% or higher is considered a diagnosis of diabetes, 5.7% to 6.4% is considered prediabetes, and an A1c of under 5.7% is considered normal.
2. A fasting plasma glucose (FPG) test, which measures the body's glucose level after fasting (no caloric intake) for eight hours. An FPG result of 126 mg/dl or greater indicates a positive diagnosis of diabetes.
3. An oral glucose tolerance test (OGTT), which measures the body's blood glucose level two hours after the intake of 75-grams of glucose. An OGTT result of 200 mg/dl or greater indicates a positive diagnosis of diabetes.
4. In someone with classic symptoms of hyperglycemia (high blood sugar), a random plasma glucose test with a result of 200 mg/dl or greater indicates a positive diagnosis of diabetes.
5. *Note, it is possible to get a diabetes-related antibody test to confirm a diagnosis of type 1 diabetes specifically (and not another kind of diabetes).

How is it Treated? People with type 1 diabetes use insulin daily in order to help control their blood sugar levels. There are two main types of insulin: basal insulin and prandial (meal-time) insulin. Basal insulin is designed to be injected once or twice per day to provide a constant low level of insulin over time. Basal insulin helps keep blood sugars at a consistent level when you are not eating, but it is not enough to cover glucose spikes after mealtime. Prandial insulins, on the other hand, are taken before mealtime and act rapidly on the body, serving to bring down the high sugar levels following meals. Other drugs like Symlin (pramlintide) can help lower appetite and lower post-meal blood sugar levels, and some people with type 1 diabetes take other drugs off-label that may also help control blood sugar. For a full overview of diabetes drugs available today, please see our diabetes drugs resource page.

Do All People with Type 1 Diabetes Wear Pumps? According to data from the T1D Exchange, about 50% of people with type 1 diabetes in the US use insulin pumps. These patients are seen at the best centers, so the overall number on pumps is likely lower. Most patients with type 1 diabetes choose to inject their insulin manually with insulin pens or syringes. 

How Many People with Type 1 Diabetes Use Continuous Glucose Monitors? According to data from the T1D Exchange, about 15%-20% of people with type 1 diabetes in the US use continuous glucose monitors (CGMs). Many patients and healthcare providers find CGMs to be incredibly valuable to diabetes management (you can read more in Adam’s account of how CGMs improved his management here). However, some patients have found that CGMs can be expensive and may not be covered under some insurance plans. CGMs are currently not reimbursed through Medicare (although hopefully that changes soon!).

What is Hypoglycemia? A blood sugar level of under 70 mg/dl (3.9 mmol/l) is typically considered hypoglycemia (low blood sugar), and can result in irritability, confusion, and even seizures and unconsciousness for extreme lows. To correct hypoglycemia, patients commonly use fast-acting carbohydrates to bring their blood sugar back to normal. In extreme cases, a glucagon injection pen can be used. According to the Mayo Clinic, symptoms of hypoglycemia are:

• Early signs and symptoms: shakiness, dizziness, sweating, hunger, irritability or moodiness, anxiety or nervousness, and headache
• Nighttime symptoms: damp sheets or bed clothes due to perspiration, nightmares, tiredness, and irritability or confusion upon waking
• Severe symptoms: clumsiness or jerky movements, muscle weakness, difficulty speaking or slurred speech, blurry or double vision, drowsiness, confusion, convulsions or seizures, and unconsciousness

What is Hyperglycemia?  A blood glucose level of over 180 mg/dl (10 mmol/l) is considered hyperglycemia (high blood sugar), and can result in nausea, fatigue, and eventually lead to long-term complications. To correct hyperglycemia, patients commonly use a dose of rapid-acting insulin. According to the Mayo Clinic, symptoms of hyperglycemia are:

• Early signs and symptoms: frequent urination, increased thirst, blurred vision, fatigue, and headache
• Later signs and symptoms: fruity-smelling breath, nausea and vomiting, shortness of breath, dry mouth, weakness, confusion, coma, and abdominal pain

What are the Complications of Type 1 Diabetes? Type 1 diabetes increases the risk of developing several medical complications. The risk of these complications decreases with better blood sugar control. Diabetes complications include:

• Heart and blood vessel problems
• Diabetic ketoacidosis (DKA)
• Nerve damage (neuropathy)
• Kidney damage (nephropathy)
• Eye damage (retinopathy)
• Foot damage and amputation
• Pregnancy complications
• Depression or diabetes distress

Does Having Type 1 Diabetes Affect My Life Expectancy? According to the JDRF, some research shows that in the absence of kidney damage, the life expectancy in people with type 1 diabetes is no different than in the general population. The literature on life expectancy in type 1 diabetes is sparse, but studies show a positive trend, due in part to advancements in therapies and technologies. A recent study published in 2012 found that people with type 1 diabetes diagnosed between 1965-1980 had a life expectancy of 69 - a major improvement compared to those diagnosed between 1950-1964, who had an average life expectancy of 53 years. However, there is still much to be done in ensuring that all patients have access to appropriate healthcare and treatments, and take care of themselves correctly, so their life expectancy becomes similar to the general population.