Table 2

Descriptive statistics and paired statistical comparisons for human topography and biomarker outcome measures from participants (n=34 unless specified) smoking the RWP in three configurations: control, bubble diffuser and electric

Mean±SDP values for statistical comparison*
ControlBubble diffuserElectricBubble diffuser versus controlElectric versus control
Topography measures
 Number of puffs70.9±37.873.4±37.2 92.5±39.8 nsP<0.01
 Puff volume (L)0.65±0.270.73±0.37 0.90±0.43 nsP<0.0001
 Puff duration (s)4.4±2.14.3±2.3 5.1±2.2 nsP<0.10
 Puff interval (s)26.2±14.428.2±17.322.6±16.1nsns
 Puff peak flow (L/min)15.8±4.817.1±5.4 17.7±5.2 nsP<0.01
 Puff average flow (L/min)10.1±3.8 11.5±4.6 11.9±4.4 P<0.05P<0.001
 Total puff volume (L)41.7±25.848.7±35.8 82.6±63.8 nsP<0.0001
 Duration of smoking (min)31.6±14.532.5±12.138.5±26nsns
Exposure measures
 Environmental CO (mg/session)980.5±368.51012±274.8 1.7±3.1 (n=25)†nsP<0.0001
 Exhaled CO boost (ppmv)51.7±19.9 (n=33)‡56.5±36.1 (n=33)‡ 0.1±1.3 nsP<0.0001
 Exhaled benzene boost (ppmv)8.5±5.4 (n=31)§8.4±4.9 (n=32)§ −0.1±0.3 nsP<0.0001
 Plasma nicotine (ng/mL)12.2±12.713.7±13.6 7.5±6.7 nsP<0.05
 Heart rate boost (bpm)13.9±10.6 (n=29)¶15.8±11.5 (n=33)¶ 9.4±9.7 (n=33)¶nsP<0.10
 Maximum heart rate (bpm)112±15.2 (n=29)¶113±13.1 (n=33)¶ 112±10.9(n=33)¶nsP<0.05
Tobacco and charcoal consumption
 Tobacco consumed (g)2.1±0.7 (n=33)**2.2±0.8 (n=34)2.0±0.8 (n=33)**nsns
 Tobacco consumed (%)21.0±7.1 (n=33)**22.2±8.0 (n=34)20.4±8.2 (n=33)**nsns
 Charcoal consumed (g)5.8±1.1 (n=34)6.0±0.9 (n=33)***nsns
 Charcoal consumed (%)55.5±11.0 (n=34)57.0±10.5 (n=33)***nsns
  • Both control and bubble diffuser use charcoal heating of the tobacco, whereas electric uses electric heating.

  • *Statistical comparisons were made between control and each configuration. Bolded entry indicates significant difference from control at a p value of 0.10 or smaller. The p values were adjusted for multiple testing.

  • †The CO monitor was inoperable during nine electric smoking sessions.

  • ‡Exhaled CO not collected for one control and one bubble diffuser session.

  • §Exhaled benzene not collected for three control and two bubble diffuser sessions.

  • ¶Heart rate data collection file was incomplete for five controls, one bubble diffuser and one electric session.

  • **Final tobacco weight not recorded for one control and one electric session.

  • ***Final charcoal weight not recorded for one bubble diffuser session.

  • bpm, beats per minute; CO, carbon monoxide; n, sample size; ns, not significant; ppmv, parts per million by volume.