Table 3.
1-year particulate matter 2.5 (PM2.5) and component species as predictors of DNA methylation (DNAm) age.
| Particle | Difference in Horvath DNAm-age for IQR (95% CI) | P | Difference in Hannum DNAm-age for IQR (95% CI) | P | N |
|---|---|---|---|---|---|
| Model framework 1 | |||||
| PM2.5 | 0.64 (0.20, 1.09) | 0.005 | 0.06 (−0.28, 0.40) | 0.74 | 940 |
| Model framework 2 | |||||
| EC | 0.27 (−0.25, 0.80) | 0.30 | −0.09 (−0.48, 0.29) | 0.64 | 940 |
| OC | 0.93 (0.37, 1.50) | 0.001 | 0.35 (−0.05, 0.77) | 0.09 | 940 |
| Sulfate | 0.59 (0.37, 0.81) | <0.0001 | 0.08 (−0.09, 0.25) | 0.36 | 940 |
| Nitrate | 0.58 (0.11, 1.04) | 0.01 | 0.30 (−0.04, 0.65) | 0.08 | 940 |
| Ammonium | 0.59 (0.26, 0.92) | 0.0004 | 0.06 (−0.18, 0.30) | 0.63 | 940 |
| Model framework 3 | |||||
| PM2.5 | 0.18 (−0.30, 0.66) | 0.45 | – | – | 940 |
| Sulfate | 0.51 (0.28, 0.74) | <0.0001 | – | – | 940 |
| Ammonium | 0.36 (0.02, 0.70) | 0.04 | – | – | 940 |
Model framework 1: adjusted for chronological age, blood cell types, temperature, pack years, smoking status, season, BMI, alcohol consumption, and education. Model frame-work 2: PM2.5 component species as independent predictors of DNAm-age adjusted for PM2.5 in addition to model 1 covariates. Model framework 3: PM2.5, sulfate, and ammonium as joint predictors of DNAm-age (given selection of sulfate and ammonium by the adaptive LASSO) adjusted for model 1 covariates. No species were selected as predictors of Hannum DNAm-age. Bold values indicate significance at P < 0.05.