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Table 5 Results from two-pollutant linear mixed-models: β -values are percent change in the outcome per IQR increase in a given pollutant, controlling for sex, age, smoking status, ethnic origin, time of day, study day, and the other pollutant in the model

From: Traffic-related air pollution exposures and changes in heart rate variability in Mexico City: A panel study

    SDNN HF LF LF/HF
  n IQR β p-value β p-value β p-value β p-value
PM2.5 (μ g/m3) Ozone (ppm)           
 5-min 3292 9.82 0.96 0.06 2.41 0.08 0.84 0.47 −1.77 0.08
65.2 −0.55 0.50 −3.82 0.07 −2.33 0.20 1.88 0.25
 30-min 3118 10.5 1.21 0.20 6.82 0.005 2.41 0.22 −4.09 0.01
66.4 −4.51 0.001 −7.81 0.02 −8.65 0.003 −0.81 0.75
 60-min 2917 8.72 1.80 0.06 7.66 0.002 4.15 0.03 −3.16 0.06
73.5 −6.97 0.0003 −13.59 0.003 −11.63 0.002 1.98 0.58
 90-min 2711 8.34 2.29 0.03 8.13 0.003 6.53 0.003 −1.49 0.42
65.0 −6.35 0.002 −14.64 0.002 −15.66 0.0001 −1.03 0.78
PM2.5 (μ g/m3) CO (ppm)           
 5-min 3240 9.82 1.02 0.049 2.37 0.08 0.83 0.47 −1.73 0.09
7.60 −1.32 0.09 −1.79 0.37 −2.45 0.15 −1.16 0.45
 30-min 3086 10.5 1.17 0.22 6.28 0.01 2.14 0.28 −3.84 0.02
10.2 −2.66 0.08 9.16 0.02 −1.52 0.63 −9.51 0.0003
 60-min 2891 8.72 1.45 0.14 6.49 0.009 3.55 0.08 −2.69 0.11
10.5 −1.77 0.32 5.81 0.20 −2.38 0.50 −7.75 0.01
 90-min 2685 8.34 1.83 0.09 6.94 0.01 5.65 0.01 −1.17 0.53
9.35 −0.59 0.74 4.87 0.27 −1.34 0.70 −6.19 0.04
PM2.5 (μ g/m3) NO2 (ppb)           
 5-min 3292 9.82 1.08 0.04 2.30 0.09 0.97 0.40 −1.53 0.13
114 −2.06 0.004 0.54 0.77 −2.68 0.09 −3.41 0.01
 30-min 3118 10.5 1.36 0.15 6.61 0.007 2.56 0.20 −3.76 0.02
137 −2.29 0.05 4.02 0.19 −1.82 0.46 −5.52 0.007
 60-min 2917 8.72 1.75 0.07 7.32 0.003 4.01 0.04 −2.98 0.07
155 −2.07 0.16 4.54 0.23 −1.34 0.65 −5.59 0.03
 90-min 2711 8.34 1.98 0.06 7.38 0.006 5.71 0.009 −1.54 0.40
156 −1.06 0.53 4.71 0.26 −0.19 0.96 −4.89 0.09
  1. Each cell contains the value for each of the two pollutants in a given model (in the order given in the left most column). Sample sizes are those used in the regression models and are the total number of repeated observations across all 16 subjects.