No causal association between serum vitamin D levels and bronchiectasis: A Mendelian randomization analysis

Area of Science:

• Medical Research
• Genetics
• Pulmonology

Background:

• Observational studies suggest a link between vitamin D deficiency and increased bronchiectasis risk.
• The causal relationship between vitamin D and bronchiectasis requires further investigation.
• Mendelian randomization (MR) analysis is a robust method for inferring causality.

Purpose of the Study:

• To investigate the causal relationship between serum 25(OH)D levels and bronchiectasis.
• To assess causality in both directions: vitamin D influencing bronchiectasis and vice versa.
• To utilize large-scale genome-wide association studies (GWAS) data for robust analysis.

Main Methods:

• Two-sample Mendelian randomization (MR) analysis using GWAS data from European ancestry.
• Primary analysis employed the inverse-variance weighted (IVW) method.
• Sensitivity analyses included MR-Egger, weighted median, simple mode, and weighted mode; pleiotropy and heterogeneity were tested.

Main Results:

• No significant causal effect of serum 25(OH)D levels on bronchiectasis was found (IVW OR = 1.550, P = 0.120).
• Sensitivity analyses confirmed the absence of a causal link in either direction.
• No significant heterogeneity, pleiotropy, or bias was detected in the instrumental variables.

Conclusions:

• This MR study found no evidence of a significant causal association between serum 25(OH)D levels and bronchiectasis.
• The findings contradict previous observational associations, suggesting no direct causal link.
• Larger sample-sized randomized controlled trials are recommended for further validation.