Impact of particulate-matter air pollution on 25-hydroxyvitamin D levels: a mendelian randomisation study.

OBJECTIVES

In observational studies, the 25-hydroxyvitamin D (25(OH)D) level in body has been found to be closely related to particulate matter (PM) air pollution. In this study, we used the two-sample mendelian randomisation (MR) method to investigate and discuss the potential causal relationship and mode of influence.

STUDY DESIGN

MR study.

METHODS

PM data (PM, PM, PM PM absorbance) came from the UK Biobank database, and 25(OH)D data came from European Bioinformatics Institute (EBI) database. The analysis was conducted utilising three prominent methods (inverse-variance-weighted [IVW], MR-Egger, weighted median, weighted mode, and simple mode). The primary emphasis was placed on IVW, accompanied by heterogeneity and horizontal pleiotropy tests. Furthermore, sensitivity analysis was undertaken.

RESULTS

The MR analysis revealed a significant association between exposure to PM and a decrease in levels of 25(OH)D (odds ratio [OR]: 0.878, 95% confidence interval [CI]: 0.789-0.977). However, no significant relationship was observed between PM exposure and 25(OH)D (OR: 0.943, 95%CI: 0.858-1.037). Further analysis indicated that the main contributor to the decline in 25(OH)D levels is linked to PM exposure (OR: 0.840, 95%CI: 0.751-0.940) and PM absorbance (OR: 0.875, 95%CI: 0.824-0.929). No heterogeneity and horizontal pleiotropy existed.

CONCLUSIONS

The MR results suggest that PM (PM, PM and PM absorbance) exposure lowers vitamin D (VD) levels, but PM2.5 was not found to have a significant effect on VD in humans.