1 in 5 with T1D has another autoimmune disease

  • Mäkimattila S & al.
  • Diabetes Care
  • 5 Mar 2020

  • curated by Miriam Tucker
  • Clinical Essentials
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Takeaway

  • More than a fifth of the Finnish population with type 1 diabetes (T1D) has another autoimmune disease (AD), most commonly hypothyroidism, celiac disease, and hyperthyroidism.
  • People with T1D should be screened for ADs throughout life.

Why this matters

  • Most studies have been in young individuals with short-term T1D, but ADs often arise later in life.

Study design

  • Study included 4758 individuals with T1D from the Finnish Diabetic Nephropathy (FinnDiane) Study, with data linked to nationwide health registries, 1970-2015.
  • Funding: Folkhälsan Research Foundation; Academy of Finland; Novo Nordisk Foundation; Finnish Diabetes Research Foundation; others.

Key results

  • An additional 1245 ADs were identified in 1087 individuals with T1D, including:
    • Hypothyroidism in 18.1%; 
    • Celiac disease in 4.4%;
    • Hyperthyroidism in 2.4%; 
    • Atrophic gastritis in 1.0%; and
    • Addison's disease in 0.4%.
  • Overall, 22.8% with T1D had ≥1 additional AD: 31.6% women and 14.9% men (P<.0001>
  • Females significantly outnumbered men for all ADs except atrophic gastritis.
  • Hypothyroidism risk increased 1.7% (P<.0001 by each increasing year of age at t1d onset.>
  • Celiac disease risk increased by 1.5% for each decreasing year of age at T1D onset (P=.048).

Limitations

  • Age at onset not known for all ADs.
  • Potential ADs underestimated because of deaths.