The causal relationship between depression and frozen shoulder: A two-sample Mendelian randomization

Area of Science:

• Genetics
• Epidemiology
• Psychiatry

Background:

• Depression is a common mental health disorder.
• Frozen shoulder (adhesive capsulitis) is a debilitating musculoskeletal condition.
• The potential causal relationship between depression and frozen shoulder remains unclear.

Purpose of the Study:

• To investigate the potential causal relationship between depression and frozen shoulder.
• Utilize a Mendelian randomization (MR) approach for robust causal inference.
• Analyze large-scale genome-wide association study data.

Main Methods:

• Selected independent genetic loci associated with depression and frozen shoulder as instrumental variables.
• Employed inverse variance weighting (IVW) as the primary analysis method.
• Conducted sensitivity analyses including weighted median, MR-Egger, heterogeneity, and pleiotropy tests.

Main Results:

• The primary IVW analysis indicated no statistically significant causal effect of depression on frozen shoulder (OR: 1.18, 95% CI: 0.91-1.53, P=0.204).
• Sensitivity analyses revealed no significant heterogeneity or pleiotropy, supporting the robustness of the findings.
• The two-sample MR analysis demonstrated no evidence of a causal association.

Conclusions:

• This study provides no evidence for a causal relationship between depression and the development of frozen shoulder.
• The findings suggest that other factors may underlie the observed association, if any.
• Larger sample sizes and diverse populations are recommended for future investigations.