Table 2

Per cent and cotinine concentration distribution of adolescents above the cotinine limit of detection (16.09 ng/mL)

>LOD°General (n=423)Men (n=214)Women (n=209)
n%Med (P25, P75)Med (P25, P75)Med (P25, P75)
Self-reported smoking (past 30 days)
 Non-smoker29529.720.5 (17.5, 22.8)*19.3 (17.4, 22.6)21.3 (18.0, 23.1)
 Smoker12848.725.4 (19.6, 72.5)26 (20.4, 71.6)24.7 (18.2, 84.9)
Age (years old)
 ≤125329.920.9 (17.9, 23.2)*21.1 (18.1, 23,8)18.8 (17.7, 22.6)
 1310233.721.2 (17.5, 23.6)21.0 (17.6, 23.8)21.6 (16.9, 23.6)
 147929.321.0 (17.7, 22.9)18.7 (17.5, 22.4)21.8 (19.5, 24.3)
 159932.721.0 (17.9, 24.6)20.5 (17.5, 22.4)21.5 (17.8, 24.5)
 ≥168051.323.6 (19.9, 69.5)25.7 (19.9, 72.5)22.1 (19.9, 67.7)
School grade
 Seventh grade12330.220.8 (17.8, 23.1)21.3 (18.0, 23.5)19.1 (17.0, 22.8)
 Eighth grade8532.321.2 (17.7, 23.2)18 (17.4, 21.3)22.3 (20.9, 25.7)
 Ninth grade1283421.6 (18.2, 25.2)21.6 (18.1, 30.3)21.6 (18.2, 23.8)
 First high school8641.823.2 (18.1, 70.7)26 (18.6, 30.3)21.3 (18.0, 64.4)
Number of cigarettes per day
 0 cigarettes29229.520.5 (17.5, 22.9)*19.4 (17.5, 22.8)21.0 (18.0, 22.9)
 1 cigarette8745.323.7 (18.3, 40.0)24.6 (19.4, 50.4)22.3 (18.1, 37.1)
 2–5 cigarettes3561.468.4 (25.5, 170.3)41 (24.1, 226.1)108.9 (60.3, 163.4)
 6 and more538.524.3 (17.2, 1022.8)21 (17.0, 892.6)863.4 (863.4, 863.4)
Smoking days over the past 30 days
 0 days29029.220.7 (17.8, 22.9)*19.4 (17.5, 22.8)21.3 (18.1, 22.9)
 1–2 days5238.822.4 (17.8, 26.3)24.0 (17.7, 31.0)22.1 (17.9, 24.7)
 3–5 days2344.226.0 (20.9, 48.4)26.0 (21.3, 48.4)28.1 (16.7, 48.1)
 6–9 days1551.726.3 (18.6, 110.3)21.6 (18.3, 356.9)41.7 (23.2, 97.6)
 10–19 days1578.930.7 (19.5, 130.6)25.5 (19.0, 69.8)119.8 (22.8, 316.5)
 20–29 days1083.3107.2 (23.5, 172.9)30.1 (22.2, 47.0)171.3 (157.1, 527.9)
 Daily1376.5329.4 (170.3, 448.3)371.1 (279.6, 448.3)66.6 (63.1, 466.2)
  • Cuernavaca and Mexico City, 2011.

  • During the past 30 days (1 month), on how many days did you smoke cigarettes?”.

  • *p Value<0.05.

  • LOD, limit of detection.