Air pollution, particulate matter composition and methylation-based biologic age.

ABSTRACT:

Background

Epigenetic age, as defined by DNA methylation, may be influenced by air pollution exposure.

Objective

To evaluate the relationship between NO₂, particulate matter (PM), PM components and accelerated epigenetic age.

Methods

In a sample of non-Hispanic white women living in the contiguous U.S. (n = 2747), we estimated residential exposure to PM_2.5, PM₁₀ and NO₂ using a model incorporating land-use regression and kriging. Predictive k-means was used to assign participants to clusters representing different PM_2.5 component profiles. We measured DNA methylation (DNAm) in blood using the Illumina's Infinium HumanMethylation450 BeadChip and calculated DNAm age using the Hannum, Horvath and Levine epigenetic clocks. Age acceleration was defined based on residuals after regressing DNAm age on chronological age. We estimated associations between interquartile range (IQR) increases in pollutants and age acceleration using linear regression. For PM_2.5, we stratified by cluster membership. We examined epigenome-wide associations using robust linear regression models corrected with false discovery rate q-values.

Results

NO₂ was inversely associated with age acceleration using the Hannum clock (β = -0.24, 95% CI: -0.47, -0.02). No associations were observed for PM₁₀. For PM_2.5, the association with age acceleration varied by PM_2.5 component cluster. For example, with the Levine clock, an IQR increase in PM_2.5 was associated with an over 6-year age acceleration in a cluster that has relatively high fractions of crustal elements relative to overall PM_2.5 (β = 6.57, 95% CI: 2.68, 10.47), and an almost 2-year acceleration in a cluster characterized by relatively low sulfur fractions (β = 1.88, 95% CI: 0.51, 3.25). In a cluster distinguished by lower relative nitrate concentrations, PM_2.5 was inversely associated with age acceleration (β = -1.33, 95% CI: -2.43, -0.23). Across the epigenome, NO₂ was associated with methylation at 2 CpG sites.

Conclusion

Air pollution was associated with epigenetic age, a marker of mortality and disease risk, among certain PM_2.5 component profiles.

SUBMITTER: White AJ 

PROVIDER: S-EPMC6754788 | biostudies-literature |

REPOSITORIES: biostudies-literature