Causal association of micronutrients and supplements with pressure ulcer: A Mendelian randomization study

Pressure ulcer (PU) is known to be associated with abnormalities of micronutrient status. However, to date, it is not clear whether a causal relationship exists between circulating levels of micronutrients and their supplementations and PU.

A two-sample Mendelian randomization (MR) study was conducted using summary statistics from Genome-Wide Association Studies (GWAS). Genetic instrumental variables (IVs) for 13 micronutrients were identified from a GWAS of 67 582 participants, IVs for supplement zinc were acquired from 18 826 cases and 44 255 880 controls, and IVs for PU were obtained from 663 PUs and 207 482 controls. The MR analysis was conducted using the MR base platform. The main analysis method was inverse variance weighted (IVW) analysis, supplemented by MR Egger, Weighted median, Weighted mode, and Simple mode analyses. Heterogeneity was assessed using Cochran's Q statistic for MR-IVW and Rucker's Q statistic for MR-Egger. Pleiotropy was determined by the MR-Egger regression. Sensitivity analysis was conducted using the leave-one-out method, and publication bias was evaluated using funnel plots.

Genetically predicted lower circulating zinc levels were found to be causally linked to the development of PU (OR = 0.758, 95%CI 0.583-0.987, P = 0.040). However, there was no significant evidence of a causal relationship between supplemental zinc intake and PU development (P > 0.05). Additionally, no causal association was observed between the other circulating micronutrients and the occurrence of PU. Furthermore, there was no indication of horizontal pleiotropy or heterogeneity among genetic variants (P > 0.05), and the robustness of the findings was confirmed through leave-one-out tests and funnel plots.

Our findings indicate a potential causal association between circulating zinc levels and decreased risk of PU. However, zinc supplementation did not demonstrate a significant reduction in the risk of PU. Further research is warranted to elucidate the underlying mechanisms through which zinc influences the pathogenesis of PU and evaluate the efficacy of zinc supplementation in the prevention and management of PU.