Autoimmune Disorders That Often Accompany Type 1 Diabetes

By Savitha Subramanian, MD

Autoimmune Disorders That Often Accompany Type 1 Diabetes

Let me introduce you to a delightful patient of mine, Rachel (not her real name).

Rachel is a 26-year-old female, who has had Type 1 diabetes mellitus (T1D, the diabetes in which the pancreas cells do not produce insulin) since the age of 7. She tells me she recently lost 10 pounds in preparation for her wedding, with surprisingly little effort. She ate a bit less and didn’t change her normal physical activity habits. However, three months later, she found that she had lost five more pounds, now without trying.

She shares that she has begun to feel anxious without reason and has developed intermittent heart palpitations. And her blood sugars, which in the past were very easy to keep within recommended target, now are not so well-controlled. She reports many high blood sugars without an identified reason for them. She looks much thinner than I recall, she is restless and shifting about in her chair as we discuss her concerns, and her heart rate is 110 beats per minute (normally her heart rate is in the 70s).

Her hands are warm and moist, and they shake as I examine them. I order a few blood tests and we soon have an answer to what is going on. Rachel is hyperthyroid, a condition in which there is more thyroid hormone in the body than normal. As we discuss further testing to understand the cause of her hyperthyroidism and what options there are to bring her thyroid hormone level back to normal, she asks an important question: could her thyroid condition could be somehow related to her diabetes?

I answer - yes!

Autoimmune disorders are conditions where proteins called antibodies are made against specific cell types or tissues. Type 1 diabetes mellitus is one such autoimmune disorder, where the insulin-making beta cells of the pancreas are destroyed, resulting in insulin deficiency and a need for lifelong insulin injections. While the exact cause of T1D is not known, genetic and environmental factors are believed to play a role, probably jointly.

In recent times, it has become clear that if you develop T1D, you can often develop one or more other autoimmune diseases. Other autoimmune conditions that can develop in individuals with T1D include thyroid disorders, gastrointestinal (gut) disorders, adrenal gland disorders and certain skin disorders.

A recent study published in 2016 analyzed data from nearly 26,000 participants with T1D who were enrolled in the T1D Exchange Registry, a voluntary registry of individuals in the U.S. with Type 1 diabetes mellitus who are routinely questioned about various aspects of their diabetes. The data were used to analyze the types and frequency of autoimmune disease in people with T1DM and to learn whether there are relationships with gender, age, and race or ethnicity. The diagnoses of autoimmune diseases were obtained from the medical records of Registry participants.

Of the study participants, 27 percent were diagnosed with at least one autoimmune disorder. And the frequency of two or more autoimmune disorders increased from 4.3 percent in study participants under the age of 13 to 10.4 percent in those over 50 years of age.

The good news is that these autoimmune diseases are easy to identify and treat. The more commonly associated autoimmune diseases are described below.

Thyroid disease

Autoimmune thyroid disorders such as Hashimoto’s thyroiditis and Graves’ disease are the most common autoimmune diseases in individuals with T1D, occurring in 15 to 30 percent of patients. Both of these thyroid conditions are characterized by the presence of antibodies to the thyroid gland, which affect thyroid gland function. Hashimoto’s thyroiditis is more common and results from destruction of the thyroid gland by antibody proteins that target thyroid tissue; this eventually leads to hypothyroidism, or low thyroid levels. On the other hand, Graves’ disease results in overactivity of the thyroid, also known as hyperthyroidism. Hyperthyroidism increases the breakdown of insulin and can cause higher blood glucoses such as those Rachel was experiencing.

The American Diabetes Association recommends that individuals with T1D should have their thyroid levels checked every 1 to 2 years. Both hypothyroidism and hyperthyroidism are easily identified and treatable.

Celiac disease

Celiac disease is an autoimmune disorder of the gastrointestinal tract caused by intolerance to gluten, a protein present in certain plants like wheat, barley and rye. Eating gluten-containing foods triggers the production of a specific type of antibody that results in abnormalities in the absorptive surface of the small intestine. This results in malabsorption of certain nutrients such as vitamins, folic acid, iron and calcium. Malabsorption of nutrients in celiac disease can result in vitamin D deficiency, anemia from vitamin B or iron deficiency, or bone loss. Unrecognized celiac disease can also affect reproductive health and can contribute to infertility and miscarriages. Celiac disease can be diagnosed by blood tests and confirmed by an intestinal biopsy, as needed. Once the diagnosis is made, a lifelong, gluten-free diet is helpful in relief of symptoms as well as returning the inner gut lining to normal function.

Autoimmune gastritis

This condition results from damage to specific cells in the stomach. Individuals can develop anemia due to poor absorption of iron or vitamin B12. This condition typically does not give you any symptoms, but should be suspected and checked for by your health team if unexplained anemia develops.

Adrenal disorders

The adrenal glands (you typically have two – one located on top of each of your kidneys) produce hormones such as aldosterone, which controls blood pressure, and cortisol, a stress hormone. Antibodies against the adrenal gland can lead to destruction of this gland and result in adrenal insufficiency. Individuals with adrenal insufficiency have increasing fatigue, decreased appetite, weight loss and, in those with diabetes, unexplained low blood sugars (hypoglycemia). Adrenal insufficiency should be suspected when insulin doses can be decreased without any identifiable cause. Also, hypoglycemia may occur with increasing frequency. Diagnosis is made by measuring cortisol levels after what are called stimulation tests. These are specific tests normally done in a clinic setting. Treatment is replacement of the adrenal hormones with steroids. Currently there are no recommendations on how to screen for adrenal abnormalities.

Vitiligo

Vitiligo is a skin disorder that results from loss of the cells in the skin that make the skin pigment melanin. The loss of skin pigment occurs in patches, giving the affected skin areas a washed-out or pale look. Unfortunately, there is no treatment for this condition other than covering visible areas with makeup.

In summary, if you have Type 1 diabetes, take charge of your well-being by asking your healthcare team if/when you have had your thyroid hormone level tested or whether there is reason to check for any of the above conditions. And it helps to know these additional autoimmune conditions are quite treatable. Just one example: Rachel is doing well and is anticipating the birth of her first child!