Causal Relationship Between Vitamin D and Anxiety and Depression: A Bidirectional Mendelian Randomization Study

Area of Science:

• Nutritional Neuroscience
• Psychiatric Genetics
• Epidemiology

Background:

• Vitamin D deficiency is increasingly recognized as a potential factor in mental health disorders.
• Understanding the causal relationship between vitamin D and mental health is crucial for developing effective interventions.

Purpose of the Study:

• To investigate the causal link between serum 25-hydroxyvitamin D (25(OH)D) levels and the risk of depression and anxiety.
• To utilize Mendelian Randomization (MR) analysis to explore genetic variations associated with these conditions.

Main Methods:

• Genome-wide association study (GWAS) summary statistics for 25(OH)D, depression, and anxiety were obtained from the IEU Open GWAS Project.
• A two-sample MR analysis was performed with 25(OH)D as the exposure and depression/anxiety as outcomes.
• Sensitivity analyses including heterogeneity and pleiotropy tests (Cochran's Q, MR-Egger) were conducted.

Main Results:

• MR analysis with 32 SNPs indicated a significant causal association between higher 25(OH)D levels and reduced depression risk (ORs ranging from 0.68-0.98 across methods).
• Genetically predicted depression showed a potential causal association with lower 25(OH)D levels (IVW OR = 0.98, p = 0.02).
• No significant causal relationship was identified between 25(OH)D levels and anxiety in either direction.

Conclusions:

• Higher serum 25(OH)D levels are associated with a lower risk of depression, suggesting its potential as an early biomarker.
• Vitamin D supplementation could be a potential intervention strategy for depression prevention and management.
• No causal association was found between 25(OH)D levels and anxiety, necessitating further research.