Type 1 Diabetes as a Causal Risk Factor for Suicide or Selfharm: A Bidirectional Mendelian Randomization Study

Area of Science:

• Genetics and Epidemiology
• Mental Health Research

Background:

• Observational studies suggest a link between type 1 diabetes (T1D) and suicidal/self-harm behaviors.
• The causal nature of this association remains unclear, necessitating further investigation.

Purpose of the Study:

• To investigate the potential causal relationship between T1D and suicidal or self-harm behaviors using a bidirectional Mendelian randomization (MR) approach.
• To assess the genetic influence of suicidal or self-harm behaviors on T1D.

Main Methods:

• A 2-sample bidirectional Mendelian randomization (MR) analysis was performed using publicly available genome-wide association study summary statistics from individuals of European descent.
• Standard MR methods (IVW, MR-Egger, weighted median) and sensitivity analyses (Cochran's Q, MR-Egger, MR-PRESSO, leave-one-out) were employed to ensure result robustness.

Main Results:

• The inverse variance weighted (IVW) method revealed a significant association between T1D and suicidal or self-harm behaviors (OR = 1.011, P = .002).
• No significant genetic influence of suicidal or self-harm behaviors on T1D was detected.

Conclusions:

• This bidirectional MR study provides genetic evidence supporting T1D as a risk factor for suicidal or self-harm behaviors.
• Findings are limited to European-descent populations, and generalizability to other ethnicities requires further study.