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Table 4 Results from single-pollutant linear mixed-models: β -values are percent change in the outcome per IQR increase in exposure, controlling for sex, age, smoking status, ethnic origin, time of day, and study day

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)           
 5-min 3314 9.82 0.97 0.06 2.36 0.08 0.86 0.46 −1.69 0.10
 30-min 3140 10.5 1.22 0.19 6.87 0.005 2.42 0.23 −4.12 0.01
 60-min 2939 8.72 1.70 0.08 7.33 0.003 3.97 0.04 −3.05 0.06
 90-min 2733 8.34 1.94 0.07 7.66 0.004 5.90 0.007 −1.64 0.37
Ozone (ppm)           
 5-min 4406 65.2 −0.98 0.09 −3.96 0.01 −2.03 0.13 2.53 0.04
 30-min 4118 66.4 −3.12 0.005 −8.36 0.003 −9.48 <0.0001 −0.93 0.66
 60-min 3832 73.5 −4.60 0.004 −15.20 0.0001 −13.22 <0.0001 2.22 0.47
 90-min 3550 65.0 −5.66 0.0008 −16.48 <0.0001 −15.45 <0.0001 1.47 0.65
CO (ppm)           
 5-min 4353 7.60 −1.17 0.06 −1.98 0.24 −1.49 0.30 0.01 0.99
 30-min 4086 10.2 −4.19 0.0006 4.13 0.22 −1.20 0.65 −4.86 0.03
 60-min 3806 10.5 −3.79 0.008 0.95 0.80 −2.17 0.47 −3.12 0.23
 90-min 3524 9.35 −2.96 0.04 0.38 0.92 −1.59 0.60 −2.09 0.42
CO2 (ppm)           
 5-min 4371 96.3 −0.63 0.24 2.86 0.053 1.21 0.34 −1.86 0.10
 30-min 4088 106 −3.38 0.001 1.23 0.66 −4.44 0.045 −5.55 0.003
 60-min 3802 104 −4.07 0.0005 −0.88 0.78 −4.55 0.07 −3.69 0.08
 90-min 3520 105 −4.00 0.003 −1.61 0.64 −3.54 0.21 −2.15 0.39
Formaldehyde (ppb)           
 5-min 1784 25.5 0.03 0.94 1.16 0.39 −0.09 0.94 −1.27 0.22
 30-min 1663 29.8 −2.55 0.04 −6.21 0.07 −6.58 0.03 −0.44 0.86
 60-min 1519 31.0 −2.95 0.06 −8.03 0.047 −3.72 0.32 4.49 0.15
 90-min 1379 34.4 −5.53 0.003 −12.09 0.01 −8.94 0.04 3.55 0.35
NO2 (ppb)           
 5-min 4406 114 −1.87 0.0004 0.75 0.60 −1.61 0.18 −2.56 0.02
 30-min 4118 137 −3.39 0.0002 0.99 0.69 −2.40 0.22 −3.22 0.06
 60-min 3832 155 −3.90 0.0007 −0.92 0.76 −2.63 0.28 −1.75 0.41
 90-min 3550 156 −3.04 0.02 −0.84 0.81 −1.96 0.49 −1.21 0.62
NOx (ppm)           
 5-min 4406 186 −3.48 <0.0001 −0.01 0.995 −2.20 0.15 −2.58 0.06
 30-min 4118 240 −4.40 0.0001 0.44 0.88 −3.70 0.13 −3.95 0.06
 60-min 3832 237 −3.53 0.005 −0.78 0.81 −2.71 0.30 −1.81 0.43
 90-min 3550 226 −2.94 0.03 −1.71 0.62 −2.33 0.41 −0.71 0.77
  1. Sample sizes are the total number of repeated observations across all 16 subjects.