Table 2.

Descriptive statistics for study subjects by site

CountryValid subjectsAge (mean ± SE)Sex (male/female)Self-reported cigarettes/day (mean ± SE)Cigarettes smoked in past 24 h (mean ± SE)% Vent* <5% Vent 5-20% Vent >20
Canada2529.0 ± 1.919/617.3 ± 1.115.7 ± 0.984016
United States (New York)2530.8 ± 2.112/1318.3 ± 0.815.3 ± 0.8241660
United States (Minnesota)2831.2 ± 1.815/1319.7 ± 1.317.3 ± 1.1502129
Australia2537.7 ± 3.912/1319.6 ± 1.218.6 ± 1.404456
United Kingdom2330.2 ± 1.411/1215.6 ± 0.914.6 ± 0.900100
  • *Percentage of cigarettes from these subjects with tip ventilation in the range indicated.