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Table 1 Symptoms, vital signs, lung function and inflammation parameters at baseline and following a 60-min period of air or e-liquid vaping in non-asthmatic and asthmatic subjects

From: Acute effects of nicotine-free and flavour-free electronic cigarette use on lung functions in healthy and asthmatic individuals

  Healthy Volunteers (N = 20) Asthmatic Volunteers (N = 10)
Placebo (no e-liquid) Experimental (with e-liquid) Placebo (no e-liquid) Experimental (with e-liquid)
T0a T60a Mean difference (95% CI Lower-Upper) T0a T60a Mean difference (95% CI Lower-Upper) T0a T60a Mean difference (95% CI Lower-Upper) T0a T60a Mean difference (95% CI Lower-Upper)
Symptoms
 Cough 0.1 ± 0.2 0.1 ± 0.2 0.025 (0.021 to 0.029) 0.1 ± 0.2 0.2 ± 0.5 0.10 (0.09 to 0.11) 0.1 ± 0.1 0 ± 0 −0.05 (−0.05 to − 0.05) 0.3 ± 0.9 0 ± 0 −0.30 (−0.32 to − 0.28)
 Chest tightness 0 ± 0 0.1 ± 0.2 0.050 (0.047 to 0.053) 0 ± 0 0.4 ± 1.1 0.38 (0.36 to 0.39) 0.1 ± 0.2 0.1 ± 0.2 0 (−0.01 to 0.01) 0 ± 0 0.6 ± 0.8 0.60 (0.58 to 0.62)
 Breathlessness 0 ± 0.1 0 ± 0.1 0 (−0.002 to 0.002) 0.1 ± 0.2 0.2 ± 0.7 0.10 (0.09 to 0.11) 0.1 ± 0.2 0 ± 0 −0.10 (−0.10 to − 0.10) 0.2 ± 0.4 0.2 ± 0.2 −0.05 (−0.06 to − 0.04)
 Secretions 0.1 ± 0.2 0.1 ± 0.2 0 (−0.004 to 0.004) 0.1 ± 0.2 0.3 ± 0.7 0.25 (0.24 to 0.26) 0 ± 0 0.2 ± 0.3 0.20 (0.19 to 0.21) 0.4 ± 0.7 0.3 ± 0.6 −0.10 (−0.11 to − 0.09)
 Wheezing 0 ± 0 0 ± 0 0 (0 to 0) 0 ± 0 0.1 ± 0.2 0.05 (0.05 to 0.05) 0 ± 0 0 ± 0 0 (0 to 0) 0.1 ± 0.3 0 ± 0 −0.10 (−0.11 to − 0.09)
 Heart rate (beat/min) 69 ± 9 63 ± 8 −6.4 (−6.5 to − 6.2) 69 ± 9 61 ± 10 −11.4 (−11.6 to − 11.1) 74 ± 10 69 ± 11 −5.2 (−5.3 to − 5.1) 78 ± 9 74 ± 10 −4.3 (−4.4 to − 4.2)
 Saturation (% O2) 98 ± 2 96 ± 7 0.25 (0.23 to 0.27) 97 ± 3 98 ± 1 0.80 (0.77 to 0.83) 98 ± 1 99 ± 1 0.40 (0.38 to 0.42) 98 ± 1 98 ± 1 0.70 (0.68 to 0.72)
 Respiratory rate (respiration/min) 16 ± 3 15 ± 3 −0.80 (−0.83 to − 0.77) 15 ± 3 15 ± 3 0.20 (0.15 to 0.25) 14 ± 3 14 ± 3 0 (−0.04 to 0.04) 17 ± 3 15 ± 3 −1.80 (−1.84 to − 1.76)
Spirometry
 FEV1 (L) 4.0 ± 0.7 4.0 ± 0.7 0.021 (0.020 to 0.021) 3.9 ± 0.7 3.9 ± 0.7 −0.021 (−0.022 to − 0.020) 3.4 ± 0.4 3.4 ± 0.4 −0.01 (−0.01 to − 0.01) 3.4 ± 0.4 3.4 ± 0.4 0.014 (0.013 to 0.015)
 FVC (L) 4.9 ± 0.9 4.9 ± 0.9 0.004 (0.002 to 0.005) 4.9 ± 0.9 4.9 ± 0.9 −0.043 (−0.044 to − 0.041) 4.4 ± 0.8 4.3 ± 0.8 −0.05 (−0.05 to − 0.05) 4.4 ± 0.8 4.3 ± 0.8 −0.069 (−0.070 to − 0.068)
 FEV1/FVC 0.80 ± 0.05 0.81 ± 0.05 0.010 (−0.016 to 0.036) 0.80 ± 0.05 0.81 ± 0.05 0.314 (0.296 to 0.332) 0.78 ± 0.09 0.79 ± 0.08 −1.10 (−1.13 to − 1.11) 0.78 ± 0.08 0.79 ± 0.08 1.550 (1.516 to 1.584)
FOT
 R5 (cm H2O.s/L) 2.656 ± 0.595 2.778 ± 0.688 0.121 (0.116 to 0.126) 2.766 ± 0.702 2.564 ± 0.633 −0.201 (−0.212 to − 0.190) 3.858 ± 0.717 3.812 ± 0.768 −0.046 (−0.054 to − 0.038) 3.583 ± 0.593 3.804 ± 0.591 0.221 (0.214 to 0.227)
 R19 (cm H2O.s/L) 2.717 ± 0.538 2.766 ± 0.597 0.048 to (0.044 to 0.053) 2.792 ± 0.592 2.739 ± 0.471 −0.054 (−0.057 to − 0.050) 3.715 ± 0.478 3.664 ± 0.531 −0.051 (−0.055 to − 0.046) 3.639 ± 0.645 3.711 ± 0.496 0.071 (0.067 to 0.076)
 R5–19 (cm H2O.s/L) −0.061 ± 0.211 0.012 ± 0.225 0.073 (0.071 to 0.075) −0.027 ± 0.309 −0.175 ± 0.468 −0.147 (−0.157 to − 0.138) 0.143 ± 0.364 0.148 ± 0.368 0.005 (0.001 to 0.009) −0.056 ± 0.208 0.093 ± 0.255 0.149 (0.144 to 0.154)
 X5 (cm H2O.s/L) −0.841 ± 0.282 −0.866 ± 0.290 −0.025 (−0.027 to − 0.023) −0.911 ± 0.456 −0.862 ± 0.386 0.050 (0.048 to 0.052) −1.329 ± 0.461 −1.230 ± 0.428 0.029 (0.026 to 0.032) −1.118 ± 0.286 −1.029 ± 0.250 0.089 (0.086 to 0.091)
 Fres (Hertz) 10.765 ± 1.844 11.157 ± 2.161 0.392 (0.373 to 0.410) 11.597 ± 3.844 11.140 ± 3.319 −0.457 (−0.468 to − 0.446) 14.269 ± 4.026 13.756 ± 3.596 −0.514 (−0.555 to − 0.472) 13.375 ± 3.319 12.860 ± 2.422 −0.515 (−0.547 to − 0.483)
 Ax (cm H2O/L/saHz) 2.597 ± 1.618 2.812 ± 1.694 0.216 (0.203 to 0.228) 3.538 ± 5.028 3.150 ± 4.134 −0.389 (−0.403 to − 0.375) 5.798 ± 3.513 5.510 ± 3.078 −0.289 (−0.328 to − 0.249) 4.557 ± 2.411 4.040 ± 2.018 −0.517 (−0.534 to − 0.499)
 IC (L) 2.698 ± 0.694 2.632 ± 0.731 −0.046 (−0.050 to − 0.042) 2.728 ± 0.628 2.697 ± 0.635 −0.019 (−0.021 to − 0.016) 2.616 ± 0.660 2.569 ± 0.695 −0.047 (−0.053 to − 0.040) 2.894 ± 0.708 2.701 ± 0.785 0.096 (0.086 to 0.107)
 TV (L) 0.837 ± 0.346 0.904 ± 0.364 0.067 (0.066 to 0.069) 0.890 ± 0.372 0.925 ± 0.422 0.035 (0.033 to 0.036) 0.975 ± 0.297 0.942 ± 0.392 −0.033 (−0.041 to − 0.025) 0.983 ± 0.308 1.090 ± 0.422 0.106 (0.101 to 0.111)
 FeNO (ppb) ND ND ND ND ND ND 25 ± 11 24 ± 11 0.40 (0.34 to 0.46) 23 ± 12 21 ± 12 0.20 (0.13 to 0.27)
 CRP (mg/L) ND ND ND ND ND ND 1.31 ± 1.38 1.00 ± 0.89b −0.47 (−0.50 to − 0.44) 1.89 ± 2.18 1.93 ± 2.22b 0.039 (0.038 to 0.040)
  1. Data are presented as mean ± standard deviation (SD)
  2. a T0 represents data recorded right before and T60 represents data recorded right after a 60-min period of vaping, b Data recorded 30 min after a 60-min period of vaping (T90)
  3. Abbreviations: Ax reactance area, BMI body mass index, CRP C-reactive protein, FeNO exhaled nitric oxide, FEV 1 forced expiratory volume in 1 second, FOT forced oscillation technique, FVC forced vital capacity, Fres resonant frequency, IC inspiratory capacity, R 5 airway resistance at 5Hz, R 19, airway resistance at 19 Hz, SD standard deviation, TV tidal volume, X 5 airway reactance at 5 Hz