DNA methylation: a potential mediator between air pollution and metabolic syndrome

Abstract

Given the global increase in air pollution and its crucial role in human health, as well as the steep rise in prevalence of metabolic syndrome (MetS), a better understanding of the underlying mechanisms by which environmental pollution may influence MetS is imperative. Exposure to air pollution is known to impact DNA methylation, which in turn may affect human health. This paper comprehensively reviews the evidence for the hypothesis that the effect of air pollution on the MetS is mediated by DNA methylation in blood. First, we present a summary of the impact of air pollution on metabolic dysregulation, including the components of MetS, i.e., disorders in blood glucose, lipid profile, blood pressure, and obesity. Then, we provide evidence on the relation between air pollution and endothelial dysfunction as one possible mechanism underlying the relation between air pollution and MetS. Subsequently, we review the evidence that air pollution (PM, ozone, NO₂ and PAHs) influences DNA methylation. Finally, we summarize association studies between DNA methylation and MetS. Integration of current evidence supports our hypothesis that methylation may partly mediate the effect of air pollution on MetS.

Keywords: Air pollution; DNA methylation; Epigenetics; Metabolic syndrome.

Fig. 1

Average air pollution (PM_2.5) across 31 countries where data were available for all three time spots of 2016, 2018, and 2019. WHO GHO repository (https://www.who.int/data/gho/data/indicators/indicator-details/GHO/concentrations-of-fine-particulate-matter-(pm2-5)) and IQair Web site (https://www.iqair.com) are used to retrieve average air quality indices (AVG). P values of one-tailed paired T tests for 2016 vs. 2018, and 2019 measures were 0.0028 and 0.067, respectively

Fig. 2

Hypothetical paths that might link criteria air pollutants exposures we discussed here to metabolic syndrome components through DNA methylation