Type 1 diabetes (T1D) is an autoimmune disease, which is caused by the immune system’s attack on healthy cells in the body. Type 1 diabetes results from the immune system’s attack on insulin-producing beta cells in the pancreas and the destruction of those cells. Most autoimmune diseases are incurable, so treatment is required for life.
People with T1D are also generally more likely to develop one or several other autoimmune diseases. A major study conducted in Finland found that 22.8% of people with T1D also live with another autoimmune disease (vs. 7.3% of people who don’t have T1D). A common genetic origin and similar environmental factors are potential causes of autoimmune diseases.
Most common autoimmune diseases for people with type 1 diabetes
Hypothyroidism is the most common autoimmune disease among people with T1D (18.1% in people with T1D vs. 6.0% in the general population). The following autoimmune diseases were the most commonly observed during the study:
- Celiac disease (4.4% in people with T1D vs. 0.99% in the general population)
- Hyperthyroidism (2.4% in people with T1D vs. 0.8% in the general population)
- Atrophic gastritis (1.03% in people with T1D vs. 0.20% in the general population)
- Addison’s disease (0.38% in people with T1D vs. 0.02% in the general population)
What is hypothyroidism?
Hypothyroidism is a dysfunction of the thyroid, a gland located at the front of the neck that produces T3 and T4 hormones. These hormones are vital to several functions of the basal metabolism. Their underproduction leads to hypothyroidism and causes several symptoms, such as fatigue, weight gain, hypersensitivity to cold, etc. Hypothyroidism is treated with medication to replace T3 and T4 hormones.
What is hyperthyroidism?
On the contrary, hyperthyroidism results from the overproduction of T3 and T4 hormones. This condition also affects the basal metabolism and causes symptoms such as nervousness, weight loss, excessive sweating, hypersensitivity to heat, accelerated heartbeat, etc. The treatment involves stopping the overproduction of hormones (e.g., through surgery) in order to reduce symptoms.
What is celiac disease?
Celiac disease is an intestinal condition caused by an intolerance to gluten, a protein found mostly in wheat, rye and barley products. In the long term, the disease leads to the malabsorption of essential nutrients. It is treated by cutting out all foods containing gluten.
What is atrophic gastritis?
Atrophic gastritis is an inflammation of the stomach’s mucous membrane that leads to the destruction of the stomach’s cells. These cells produce a substance that is essential (i.e., an “intrinsic factor”) for the absorption of vitamin B12. The vitamin B12 deficiency resulting from atrophic gastritis leads to a decrease in red blood cell count (i.e., anemia).
What is Addison’s disease?
Addison’s disease is caused by a dysfunction of the adrenal glands, located above the kidneys. These glands produce several hormones, including cortisol, which is necessary for basic bodily functions such as the regulation of blood pressure, blood sodium level and blood sugar. The main symptom of Addison’s disease is severe fatigue. The disease can be treated with cortisol replacement medication.
Gender and age as risk factors
The Finnish study also found that women with T1D are twice as likely as men with T1D to develop an additional autoimmune disease.
The risk of developing an additional T1D-related autoimmune disease also increases with age. It’s very important to follow up on a regular basis with your healthcare team and to let them know of any new symptoms.
We’re looking to understand the prevalence of other autoimmune diseases in people who are living with type 1 diabetes in Quebec.
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- Makimattila, S., Harjutsalo, V., Forsblom, C., & Groop, P.-H. (2019). Every fifth patient with type 1 diabetes suffers from an additional endocrinological autoimmune disease – a Finnish nationwide study. Endocrine Abstracts. doi: 10.1530/endoabs.63.oc2.1