Impact of Particulate Matter Air Pollution on 25-Hydroxyvitamin D Levels: A Mendelian Randomization Study

Background In observational studies, the 25-hydroxyvitamin D (25(OH)D) level in body has been found to be closely related to Particulate matter air pollution (PM). In this study, we employed the two-sample Mendelian randomization method (MR) to investigate and discuss the potential causal relationship and mode of influence. Methods PM data (PM 10 , PM 2.5−10 , PM 2.5, PM 2.5 absorbance) came from the UKBiobank database and 25(OH)D data came from the EBI database. The analysis was conducted utilizing three prominent methods (Inverse-variance weighted (IVW), MR-Egger, weighted median, weighted mode, and simple mode). The primary emphasis was placed on IVW (random effects), accompanied by heterogeneity and horizontal pleiotropy tests. Furthermore, sensitivity analysis was undertaken. Results The Mendelian randomization analysis revealed a significant association between exposure to PM 10 and a decrease in levels of 25(OH)D (OR: 0.878, 95%CI: 0.789–0.977). However, no significant relationship was observed between PM 2.5 exposure and 25(OH)D (OR: 0.858, 95%CI: 0.728–1.012). Further analysis indicated that the main contributor to the decline in 25(OH)D levels is linked to PM 2.5−10 exposure (OR: 0.840, 95%CI: 0.751–0.940) and PM 2.5 absorbance (OR: 0.875, 95%CI: 0.824–0.929). No heterogeneity and horizontal pleiotropy existed. Conclusions The MR results suggest that PM exposure lowers VD levels by reducing UV rays, and no significant PM2.5 impact on VD within the human body has been found. Considering the important mediator of VD in osteoporosis, we recommend that people in highly polluted areas supplement appropriate amounts of VD.