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. 2014 Jan 2;9(3):448–458. doi: 10.4161/epi.27584

Table 3. Association between air pollution exposure over the 4-week period preceding medical examination on gene-specific DNA methylation according to the smoking status.

Methylation mean ratio for an interquartile range increase in air pollution
  Particle number Black carbon Sulfate Ozone
(March to August)
  Estimate 95% CI Estimate 95% CI Estimate 95% CI Estimate 95% CI
F3        
Never smokers 0.739 0.648, 0.0.844 0.863 0.793, 0.939 0.936 0.828, 1.058 1.032 0.773, 1.377
Former and current smokers 0.719 0.644, 0.801 0.882 0.825, 0.943 1.037 0.948, 1.135 1.106 0.882, 1.387
ICAM-1        
Never smokers 0.910 0.826, 1.002 1.005 0.943, 1.071 0.976 0.899, 1.059 0.779 0.640, 0.948
Former and current smokers 0.880 0.810, 0.957 1.011 0.964, 1.060 0.933 0.877, 0.993 0.747 0.642, 0.868
TLR-2        
Never smokers 0.911 0.800, 1.037 1.016 0.943, 1.094 0.939 0.848, 1.039 0.864 0.681, 1.098
Former and current smokers 0.958 0.859, 1.069 1.040 0.981, 1.102 1.007 0.932, 1.088 0.953 0.789, 1.152
Change in methylation (% 5mC) for an interquartile range increase in air pollution
  Particle number Black carbon Sulfate Ozone
(March to August)
  Estimate 95% CI Estimate 95% CI Estimate 95% CI Estimate 95% CI
IFN-γ        
Never smokers –0.805 –1.664, 0.053 –0.651 –1.159, –0.143 1.197 0.411, 1.984 2.734 1.080, 4.388
Former and current smokers –0.870 –1.729, –0.012 –0.288 –0.796, 0.220 0.377 –0.410, 1.163 1.401 –0.253, 3.055
IL-6        
Never smokers 2.877 1.221, 4.534 0.553 –0.329, 1.436 –0.367 –1.738, 1.005 –3.536 –6.474, –0.598
         
Former and current smokers 0.886 –0.770, 2.543 0.896 0.014, 1.779 0.662 –0.710, 2.034 –2.028 –4.966, 0.910

Variables included in the models: f1(air pollutant)b, f2(temperature)b, f3(relative humidity)b, smoking status*f1(air pollutant)b, age, body mass index, smoking status, diabetes status, statin use, % neutrophils in blood count, % lymphocytes in blood count, seasonal sine and cosine, season, and methylation batch. f1(air pollutant), f2(temperature), and f3(relative humidity) represent the distributed-lag functions with sets of coefficients constrained by a natural spline (with 3 degrees of freedom) that correspond to the air pollution, temperature, and relative humidity associations at lags 0 and 27 days.