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What are the most common co-existing auto-immune diseases that occur for people with T1D?

Recently a client asked questions about which other autoimmune diseases (AID) are more common for people with Type 1 Diabetes (T1D). 

It is an important question that I think requires an in-depth overview.  This question led to an in-depth discussion at our next Integrated Diabetes Services staff meeting.  It turns out that very few of our team were told much about other autoimmune diseases either when we were diagnosed, or at any time along the way.  A few of us were told about the connection between some people’s genetics and autoimmune thyroid disease and Celiac disease.

While some people have monoglandular (consisting of only 1 gland) T1D, other people have polyglandular (consisting of more than 1 gland, or many, glands) AID, while still other people have a variety of glandular (Endocrine or Exocrine related) and non-glandular (having nothing to do with the Endocrine system) AID.

An interesting piece of trivia:

There are more than 80 autoimmune diseases identified in the world today.

Large studies looking at AID in thousands of people with T1D over a 30-to-50-year time span show around a 20 to 35% co-occurrence of at least 1 other AID. 

  • The longer the duration of living with T1D, the more common it is to see an additional AID present.
  • It is almost twice more likely to have an additional AID if you are biologically a woman compared to a man.

What are the most common co-existing auto-immune diseases that occur for people with T1D

In a published study done in 2020 in Finland titled “Every Fifth Individual With Type 1 Diabetes Suffers From an Additional Autoimmune Disease: A Finnish Nationwide Study” it showed that there were:

  • 20% of people with T1D had 1 additional AID
  • 3% of people had 2 additional AIDs
  • 0.13% had 3 additional AIDs
  • 0.02% had 4 additional AIDs together with T1D

Of course, if someone has T1D that counts as AID number 1.

In comparison in the same study:  only 7.3% of people in the study who did not have T1D, did have 1 AID, and only 0.7% had 2 AIDs.

What are the most common co-existing auto-immune diseases that occur in people with T1D?

1. The most common glandular AIDs that co-occur with Type 1 Diabetes, are autoimmune thyroid diseases.  Autoimmune thyroid diseases include:

2. According to a study published in 2020 in the World Journal of Diabetes titled “Type 1 diabetes and associated autoimmune diseases”, the second most common AID that co-occurs in about 15% of people with T1D is atrophic autoimmune gastritis (otherwise called Type A Gastritis).

Autoimmune atrophic gastritis is a chronic inflammation and thinning in the lining of the stomach.  It can be mild and cause no symptoms, or can be severe and cause pain, tenderness, and signs and symptoms caused by Pernicious Anemia (low Vitamin B12 and iron).  Symptoms of anemia (fatigue, fast heart rate, shortness of breath, dizziness and/or nerve tingling and numbness) are common symptoms that bring people to the doctor’s office.  Of note, other studies indicate the incidence may be closer to 1-12% of people with T1D also have atrophic autoimmune gastritis.

3. Celiac disease co-occurs in 3% – 12% of people with T1D

4. Addison’s disease in 0.4-1% of people with T1D. 

5. Vitiligo occurs in 1-7% of people with T1D.

While the percentage of people living with 1 or more additional AID appears low, if you compare the frequency of 1 or more AID to co-occur in someone with T1D to people who do not have T1D, there is a 2-5 times higher likelihood that there will be an additional 1 or more AID.

It is recommended that people are tested at diagnosis of T1D for autoimmune thyroid disease and celiac disease.

According to some studies, it appears that testing for atrophic autoimmune gastritis should also take place.   There is a higher frequency of Celiac disease in people with T1D who are diagnosed at a young age, and a higher frequency of people with T1D diagnosed as an adult have a higher frequency of atrophic autoimmune gastritis.  Regardless of the age of T1D diagnosis, it is recommended to screen for thyroid disease, Celiac disease, or atrophic autoimmune gastritis at any time that symptoms or blood tests indicate one of these autoimmune diseases may exist.

Family Ties

There is a high incidence of family members of people with T1D with autoimmune markers for a variety of AID compared to the general population.  Even if you are, or your child is, the only person in your family with T1D, there is a very strong likelihood that other family members have other AID.

The moral of the story?

If you are living with T1D and you have new symptoms that are not likely related to T1D, ask your family members if anyone else has the same symptoms. If they do, ask if they have an AID diagnosis and tell your doctor.  If you have symptoms that sound different than other family members experience, or you have symptoms that a doctor has not been able to connect to a diagnosis yet, be sure to point out that it is far more common for people living with T1D to have another AID than the general population.  If you look up your symptoms and wonder if you have a specific AID, do not be deterred by any healthcare provider that dissuades you from getting a proper evaluation by a specialist such as an Endocrinologist, Rheumatologist, Gastroenterologist, or Dermatologist, depending on the symptoms.

It can take an average of 3-5 years (or longer) and an average of 5-10 doctor’s appointments to receive a diagnosis for certain, less common, AID.  Even though certain AIDs are considered “rare” in the general population, they are far more common in people living with T1D!