Only 5% of people with diabetes have been diagnosed with type 1, by far the least common form of the disease1. In this lifelong condition, the pancreas, a large organ behind the stomach, stops producing a hormone known as insulin. Insulin’s job is to break down the carbohydrates you eat and turn them into glucose, or “blood sugar”. 

The glucose travels through the bloodstream, providing energy and nourishment. Without insulin to let glucose into the cells, the body is literally starving for energy. Meanwhile, excess glucose can’t be broken down, so it accumulates in the bloodstream where it can cause serious damage.

People with type 1 diabetes must take insulin injections to survive. For this reason, type 1 diabetes is sometimes called “insulin dependent” diabetes. 

Because type 1 diabetes is usually diagnosed in children, teens and young adults, it also used to be known as “juvenile diabetes”.

Scientists are still working to identify the exact cause of type 1 diabetes, but it is classified as an “autoimmune disease”. In most people with this form of the diabetes, the body's own immune system starts destroying the insulin-producing cells in the pancreas. Several factors may contribute to this, including genetics and certain viruses.

Once the pancreas stops producing insulin, the symptoms or type 1 come on very rapidly. These include:

  • Increased thirst
  • Frequent urination
  • Bedwetting (in children who no longer wet the bed during the night)
  • Extreme hunger
  • Unintended weight loss
  • Irritability and other mood changes
  • Fatigue and weakness
  • Blurred vision
  • Vaginal yeast infections in women

Consult your doctor right away if you, or your child, develop any of these symptoms.

Type 1 diabetes has to be managed so it doesn’t damage your body over time. Uncontrolled blood sugar can cause a variety of serious complications:

  • Diabetes dramatically increases the risk of cardiovascular problems, including coronary artery disease, heart attack, stroke, narrowing of the arteries, and high blood pressure.
  • Excess glucose can damage tiny blood vessels that supply blood to the nerves in the hands and feet. This nerve damage, known as diabetic neuropathy, can cause tingling, numbness, burning or pain at the ends of the fingers and toes. If neuropathy is allowed to progress, a person may eventually lose all feeling in the affected limbs.
  • Nerve damage and poor blood flow in the feet lead to foot complications. People may injure their feet and not notice due to lack of sensation, and cuts and bruises heal poorly. In advanced cases, toe, foot, or leg amputation may be necessary.
  • Nerve damage in the gastrointestinal tract can lead to nausea, vomiting, diarrhea or constipation.
  • In men, damage to small blood vessels in the penis can lead to erectile dysfunction.
  • Nephropathy is damage to blood vessels in the kidneys. Over time, nephropathy may lead to kidney failure. If that occurs, a person needs to go on dialysis or have a kidney transplant.
  • When diabetes damages the tiny blood vessels of the retina, it can cause a condition known as diabetic retinopathy, which potentially leads to blindness. Diabetes also increases the risk of cataracts and glaucoma.
  • Diabetes increases the risk of bacterial and fungal infections of the skin.
  • During pregnancy, high blood sugar levels can be dangerous for both  mother and baby. Unless diabetes is carefully managed, there is an increased risk of miscarriage, stillbirth and birth defects. In the mother, complications may include high blood pressure and preeclampsia. 

While type 1 diabetes has no cure, with proper care, people can travel well through life with type 1 diabetes. This requires a combination of insulin, blood sugar management, support and education:

  • Medication (Insulin): Every person with type 1 diabetes must learn to monitor their blood glucose and administer their insulin using insulin pens or syringes, or an insulin pump. Medical supervision may be required to determine which insulin regimen works best for each individual, and make adjustments in response to daily life.
  • Exercise: Understanding how exercise affects the blood sugar and how to adjust insulin to prevent hyper- and hypo- glycemia requires support from providers knowledgeable in Type 1 diabetes.
  • Nutrition: Every person with diabetes benefits from working with a RD, CDE to understand the relationship between food, blood glucose, and insulin needs.
  • Daily testing: Daily monitoring of blood glucose is an essential aspect of managing type 1 diabetes. The American Diabetes Association recommends that people with type 1 diabetes and insulin-dependent people with type 2 diabetes test their blood at least three times a day. If you have been diagnosed with type 1 diabetes, your diabetes educator will explain the testing process and help you plan a testing routine. When to test is something the patient and care team work out together, depending on a person’s age, activity level, general health, and other factors. Some common testing situations include:
    • Before each meal
    • 1 or 2 hours after a meal
    • Before a snack
    • In the middle of the night
    • Before exercising
    • During and after physical activity
    • If you think your blood sugar may be high, low, or dropping.  
    • When you're sick or under stress
    Your doctor will set your blood glucose target based on the following factors:
    • How long you have had diabetes
    • Age
    • Hypoglycemic events and awareness
  • A1C Testing: Once a person has been diagnosed, their doctor will periodically prescribe an A1C test to determine the level of blood sugar control. This blood test provides information about a person’s average blood sugar levels over the three months preceding the test. An A1C test result is reported as a percentage.
  • Ketone Testing: Ketone are a chemical the body produces when there isn’t enough insulin in the blood and the body starts using fat for energy instead of glucose. This is more likely to occur in type 1 diabetes than in type 2. Ketones upset the chemical balance of your blood and are toxic to the body. Combined with high blood glucose, ketones in the blood are a sign of poorly managed diabetes. Ketones can be detected through a simple urine test you can buy at the pharmacy. Talk to your doctor at once if your urine results show moderate to large amounts of ketones.
    Signs of Elevated Ketone Levels
    • Blood glucose of more than 300 mg/dl
    • Nausea, vomiting and/or abdominal pain
    • Feeling tired all the time
    • Thirst and dry mouth
    • Flushed skin
    • Breathing difficulties
    • A strange, fruity breath odor
    • Feeling confused or "in a fog"

Taking steps to manage your diabetes does more than lower your blood glucose and improve your health. It significantly reduces your risk of serious long-term complications and helps build the confidence you need for successful lifelong diabetes management.

The Diabetes Care Program at Marin General Hospital provides a continuum of expert care and resources for diabetes patients, their families, and caregivers. With the proper education, support, and medical supervision, patients can learn to successfully manage their diabetes and live healthier lives.

Click here to listen, as Dr. Linda Gaudiani explains how Marin General Hospital partners with you to help make life with diabetes a full and satisfying journey


  1.  ADA: