Greg has type 1 diabetes, so when he started feeling sluggish and tired all the time — even after getting a good night's sleep — he chalked it up to high blood sugar levels. But he'd been doing a great job sticking to his meal plan, exercising, and taking his diabetes medicines, and his blood sugar checks showed his levels were in a healthy range. What was going on? Greg went to see his doctor, and tests revealed that he had a problem with his thyroid.

People with type 1 diabetes have a greater risk for certain health problems (like Greg's thyroid problem). Like type 1 diabetes, these are often autoimmune disorders.

Most teens with type 1 diabetes never need treatment for any other autoimmune disorder. But some do. So it can help to find out more about the diseases that can happen to people with type 1 diabetes.

What Are Autoimmune Disorders?

In autoimmune disorders, a person's immune system mistakenly attacks the body's healthy tissues as though they were foreign invaders. If the attack is severe enough, it can affect how well that body part works. For example, type 1 diabetes is an autoimmune disease that affects the pancreas. In type 1 diabetes, the pancreas can't make insulin because the immune system attacks the pancreas and destroys the cells that make insulin.

People with type 1 diabetes are also more prone to having other autoimmune problems. Doctors aren't exactly sure why autoimmune diseases happen, but a person's genes probably play a role. Doctors think this is because family members of people with type 1 diabetes are more likely to have autoimmune diseases, too.

Although certain autoimmune disorders are linked to diabetes, they are not actually caused by the diabetes — they're just more likely to happen to people who have the disease. Autoimmune diseases that people with type 1 diabetes are more likely to get include:

• thyroid disorders
• celiac disease
• Addison's disease

Sometimes people develop one or more of these problems before they develop type 1 diabetes. And sometimes doctors discover these other autoimmune diseases around the same time they find out that a person has type 1 diabetes. In other people, the disorder may not develop until months or years after they've been diagnosed with type 1 diabetes.

Thyroid Disorders

The thyroid is a gland located behind the skin and muscles at the front of the neck, just at the spot where a bow tie would rest. The thyroid makes hormones that help control metabolism and growth. These hormones play a role in bone development, puberty, and many other body functions.

Thyroid disease is fairly common in people with type 1 diabetes — about 15% to 20% show some signs of autoimmune disease of the thyroid gland.

Thyroid disease can cause the thyroid gland to make too much thyroid hormone (hyperthyroidism, pronounced: hi-per-thi-roy-dih-zem, also known as overactive thyroid) or too little hormone (hypothyroidism, pronounced: hi-po-thi-roy-dih-zem, also known as underactive thyroid).

People with overactive thyroid and underactive thyroid also may have a thyroid gland that is larger than normal. This is called a goiter (pronounced: goy-ter). Normally, you can't see the thyroid gland, but when a person has a goiter, the gland bulges so it's visible.

Overactive thyroid can cause:

• nervousness
• irritability
• increased perspiration
• intolerance to heat
• fatigue
• difficulty sleeping
• a fast heartbeat
• irregular menstrual periods in girls
• muscle weakness
• weight loss even though the person is eating more than usual
• eye irritation, swelling, and bulging

Someone with a mildly underactive thyroid may feel just fine — in fact, the condition might cause no symptoms at all. However, symptoms can become more obvious if underactive thyroid gets worse. People with underactive thyroids might:

• feel depressed and sluggish
• gain weight, even though they're not eating more or getting less exercise than usual

They might also have:

• slow growth in height
• slow sexual development
• irregular menstrual periods (in girls)
• muscle weakness
• dry skin
• hair loss
• poor memory
• difficulty concentrating

To check for thyroid disorders, the doctor may ask whether you've had the symptoms of a thyroid problem (see the lists above). He or she may also feel your neck for an enlargement of the thyroid gland or order blood tests to check the levels of thyroid hormones in your blood.

To treat underactive thyroid, people may need to take pills that keep their thyroid hormone levels normal. Doctors may prescribe pills or other treatments for people with overactive thyroid to bring their thyroid hormone levels back down to normal and keep them there.

Celiac Disease

Celiac disease is another type of autoimmune disorder that's more likely to affect people with type 1 diabetes. In fact, about 1 in 20 has it. Celiac disease affects the intestine's ability to tolerate a protein called gluten, which is found in grains like wheat, rye, and barley.

When people with this disease eat foods containing gluten, their immune system reacts to the protein. Over time, eating the protein damages the small intestine and prevents it from properly absorbing nutrients from food.

Some people with celiac disease have no symptoms, but others may have frequent diarrhea, abdominal pain, gas, bloating, weight or appetite loss, or fatigue. Some have growth problems because they aren't getting enough nutrients.

If it's not treated, celiac disease can lead to serious health problems during childhood or adulthood, including hypoglycemia, osteoporosis (a disease that causes brittle, fragile bones), and certain types of cancer.

If you have type 1 diabetes, your doctor will do a blood test to check for celiac disease, even if you don't have symptoms. If the tests indicate that you might have it, the doctor also might need to remove a piece of tissue from the small intestine and examine it under a microscope (this is called a biopsy) to tell for sure whether you have celiac disease.

People who have celiac disease need to follow a special diet that's free of foods that contain gluten. To make sure you're eating the right gluten-free foods to stay healthy and help keep your blood sugar levels in a healthy range, you can meet with a registered dietitian. He or she can help you learn about choosing and preparing tasty gluten-free foods.

Addison's Disease

Addison's disease is an autoimmune disease that affect the adrenal glands, which are located just above the kidneys. The adrenal glands produce hormones, including cortisol (pronounced: kor-tuh-sol) and aldosterone (pronounced: al-dass-tuh-rone).

These hormones control many body functions, like blood pressure, fluid balance, heart function, use of insulin, and a person's sense of alertness and well-being. If someone has Addison's disease, the adrenal glands don't produce enough cortisol or aldosterone or both.

Signs and symptoms of Addison's disease start slowly. Someone might have:

• fatigue
• muscle weakness
• appetite loss
• weight loss
• nausea, vomiting, and diarrhea
• dizziness and low blood pressure
• changes in skin color (like darkening where the skin creases)
• irritability
• depression
• irregular periods

For about 1 in 4 people with Addison's disease, symptoms don't appear until they're triggered by a stressful event, such as illness or an accident. These symptoms can be more severe and come on suddenly, so getting medical help right away is important.

When doctors think that a person has Addison's disease, they can perform tests, including urine and blood tests, to diagnose it. Addison's disease is treated with pills that bring adrenal hormone levels up to normal.

What You Can Do

Although you can't prevent the health problems related to type 1 diabetes, the good news is that thyroid disorders, celiac disease, and Addison's disease can usually be treated successfully.

If you have type 1 diabetes, your doctor will check for these problems during your regular checkups. That's one reason why it's important to keep your doctors' appointments and let your health care team know if you're having any symptoms of these conditions.

Reviewed by: Steven Dowshen, MD
Date reviewed: October 2010