Study Finds Causal Links Between Type 1 Diabetes and Key Autoimmune Skin Diseases

The MR analysis revealed a causal relationship between type 1 diabetes and systemic lupus erythematosus (SLE), multiple sclerosis (MS), and rheumatoid arthritis (RA) in Europe. However, the researchers observed no causal relationship between T1DM and SLE in East Asia.

The findings showcase the importance of regularly monitoring relevant immunological markers of RA, SLE, and MS in T1DM patients and taking preventive measures, the study stated.

Type 1 diabetes, an autoimmune disorder characterized by the destruction of insulin-producing beta cells in the pancreas, has long been associated with a range of other autoimmune conditions. T1DM may be associated with various autoimmune diseases, but there is no clarity on the causal relationship between T1DM and autoimmune skin diseases.

Against the above background, Xiaolan Li, Department of Dermatology and Venereology, The Second Affiliated Hospital of Kunming Medical University, Kunming, China, and colleagues aimed to analyze the causal association between T1DM and autoimmune skin diseases for prevention and management better. They used MR to clarify this issue and understand the unique effects of T1D on autoimmune skin diseases from a genetic perspective.

For MR analysis, the summary statistical data on T1DM and nine autoimmune skin diseases in European populations were extracted. The analysis was subsequently replicated in East Asian populations.

In the MR estimation, MR-Egger, inverse variance-weighted (IVW), simple mode, weighted median, and weighted mode methods were utilized. Outliers were removed using MR-PRESSO, and horizontal pleiotropy was evaluated with MR-Egger. Furthermore, a multivariable Mendelian randomization analysis was performed to determine if type 1 diabetes has an independent effect on autoimmune skin diseases while accounting for potential confounders.

The following were the key findings of the study:

· In Europe, the MR estimated based on IVW method indicated a causal association between genetically determined T1DM and systemic lupus erythematosus (OR = 1.38), rheumatoid arthritis (OR = 1.15), as well as multiple sclerosis (OR = 1.17), but there is no association between T1DM and atopic dermatitis (AD), lichen planus (LP), vitiligo, alopecia areata (AA), hidradenitis suppurativa (HS), and systemic sclerosis (SS).

· After adjusting for time spent watching television, body mass index, type 2 diabetes mellitus, and body fat percentage, a causal relationship was found between T1DM and SLE (OR = 1.29), RA (OR = 1.28), and MS (OR = 1.11).

· No genetic causal association was found between TIDM and SLE, and AD in East Asia.

· These results did not exhibit horizontal pleiotropy, and the “leave-one-out” analysis demonstrated result stability.

"Our Mendelian randomization study suggests a causal relationship between type 1 diabetes and SLE, RA, and MS in European populations. However, we found no evidence of a causal link between T1D and AD, vitiligo, LP, HS, AA, or Sjögren's syndrome (SS)," the researchers concluded.

"Consequently, it is essential to regularly monitor relevant immunological markers for SLE, RA, and MS in patients with T1D and implement appropriate preventive measures."

Reference:

Liu J, Xu Y, Liu Y, Zhu Y, Li X. Associations between type 1 diabetes and autoimmune skin diseases: Mendelian randomization analysis. Heliyon. 2024;10(12):e32781. Published 2024 Jun 10. doi:10.1016/j.heliyon.2024.e32781