Type 1 diabetes (T1D) is an autoimmune disease that happens when the immune system mistakenly attacks the pancreas’ insulin-producing cells. But, T1D is often not the only autoimmune disease a person might face. In fact, people living with one autoimmune disease are unfortunately more likely to develop another compared to those without.
Some autoimmune diseases that can occur alongside T1D include thyroid diseases (like Hashimoto’s or Graves’ disease), celiac disease (reaction to gluten from food), some joint or dermatology problems (e.g., lupus, rheumatoid arthritis, psoriasis, vitiligo, etc.) and some neurological diseases such as multiple sclerosis.
Is this unfortunate coexistence of 2 or more autoimmune diseases frequent? What happens when T1D and other autoimmune diseases coexist? Do people living with additional autoimmune diseases face greater challenges in regulating their blood sugar or preventing hypoglycemia? Are they at higher risk of developing complications such as cardiovascular disease, retinopathy, neuropathy, or kidney disease? And could managing multiple autoimmune diseases increase the likelihood of mental health struggles, including depression or emotional difficulties related to diabetes care? Thanks to data from the BETTER registry, we were able to explore these important questions.
Other autoimmune diseases are common
Out of 3,222 adults with T1D in the BETTER registry, over one-third (36.3%, or 1,170 people) also had at least one other autoimmune disease. These additional conditions were especially common among women and older adults. The most frequent were thyroid diseases, including both underactive (hypothyroidism) and overactive (hyperthyroidism) thyroid.
Autoimmune disease and severe low blood sugar episodes
People with additional autoimmune diseases were more likely to report having had severe hypoglycemia — dangerous episodes of very low blood sugar, since their T1D diagnosis. This may indicate that managing blood sugar is even more challenging for this group.
Higher risk of vascular complications
Those with other autoimmune conditions also experienced more vascular complications, such as heart and blood vessel problems. This was true even after considering differences in age and sex, highlighting an important health risk.
Greater emotional challenges
When it comes to mental health, people with multiple autoimmune diseases scored higher on depression scales and had higher use of depression or anxiety medications, suggesting they may face more emotional difficulties. However, their levels of diabetes-specific stress (worry or burnout directly related to diabetes) were similar to those with only T1D.
Why it matters
This study contributes to a growing understanding of what it might mean to live with other autoimmune disease(s) for people with T1D. The high frequency and possible associated physical and mental health consequences are probably underestimated by a lot of healthcare professionals. This data obtained from the BETTER registry shows that living with both T1D and other autoimmune diseases may bring extra health risks and emotional burdens. It highlights the importance of providing personalized medical and psychological support to help people manage these overlapping conditions.
More research is needed to figure out which autoimmune diseases create the greatest risks and how best to support people living with multiple conditions—for both their diabetes and mental well-being. In the long term it is hoped that strategies to prevent both type 1 diabetes and other auto-immune conditions can be developed.
Want to get involved?
If you live with T1D and want to contribute your lived experience to research, consider joining the BETTER registry! Your experiences can make a difference.
Reference:
Locatelli CAA, Talbo MK, Messier V, Grou C, Lebbar M, Mulvihill EE, Brazeau AS, Rabasa-Lhoret R. In adults living with type 1 diabetes, additional autoimmune diseases are associated with more chronic complications and depression. A BETTER registry analysis. Diabetes Metab. 2025 Jun 4:101667. doi: 10.1016/j.diabet.2025.101667. Epub ahead of print. PMID: 40544067.
Written by: Cassandra Locatelli, research assistant
Reviewed by:
- Sarah Haag, Clinical Nurse, B.Sc.
- Anne-Sophie Brazeau, RD, PhD
- Rémi Rabasa-Lhoret, MD, PhD
- Darrin Davis, Ayush Chadha, Pamela Dawe, patients partners
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