Greater residential greenness is associated with reduced epigenetic aging in a population survey in North Carolina
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Background and aim. Epigenetic age acceleration (EAA) or the difference between DNA methylation-predicted age and chronological age is affected by environmental and social factors, and predictive of systemic diseases. This study assessed associations between residential greenness and EEA, and between EEA and systemic inflammation.
Methods. This analysis applied three alternative EEA formulas proposed by Horvath and Hannum et al. in 2013, and Li et al. in 2018 to Illumina EPIC DNA methylation data on 116 blood samples from adult participants of a cross-sectional survey in North Carolina. Inflammation score was based on a sum of 18 biomarkers including multiple cytokines, which were dichotomized at 90th percentile of sample distribution. ELISA tests were applied to determine Helicobacter pylori, Toxoplasma gondii and cytomegalovirus IgG seropositivity, and calculate the number of chronic infections. Proportion of vegetated land cover (trees, shrubs, and grass) was calculated within 500 m of each residence using high resolution landcover data.
Results. Li’s epigenetic age formula [Li et al. 2018. Exposure to polycyclic aromatic hydrocarbons and accelerated DNA methylation aging; EHP 126] produced the strongest correlation between DNA methylation age and chronological age. Using this formula, an interquartile increase (23%) in vegetated land cover was associated with -2.3 (95% CI -3.4; -1.2) years predicted change in EEA in generalized additive regression analysis adjusting for obesity, sex, race, chronic infections, daily screen time and two-dimensional spline function of geographic coordinates. Individuals with three chronic infections had 10.3 (5.9; 14.7) years greater adjusted EEA than those with no infections. One extra year of EEA was predictive of 6.2% (2.5%; 10.2%) greater mean adjusted inflammation score in Poisson regression.
Conclusions. This is the first study to demonstrate that residential greenness is associated with reduced epigenetic aging.
Keywords. Epigenetic age, DNA methylation, inflammation, greenness, green space.
This abstract does not represent EPA policy.