Table 1.

Summary statistics for smoking variables across treatment groups

(A) Demographics and smoking history among adolescent and adult smokers
N = 403Gender (% male)Mean age (SD) yearsMean CPD (SD) yearsMean duration (SD) years
Adolescent smokers
    Study 19440.416.6 ± 1.212.7 ± 5.13.4 ± 2.0
    Study 216552.717.1 ± 1.110.3 ± 4.52.6 ± 1.5
    Study 31414.316.8 ± 1.211.4 ± 4.23.3 ± 1.7
    Pooled27346.516.9 ± 1.211.2 ± 4.82.9 ± 1.7
    P-value (difference across studies 1-3)-0.01<0.01<0.01<0.01
Adult smokers
    Study 44944.944.3 ± 11.419.9 ± 0.725.5 ± 11.4
    Study 54360.542.2 ± 16.218.1 ± 1.824.6 ± 15.5
    Study 63844.746.8 ± 13.09.7 ± 3.2NA
    Pooled13050.044.3 ± 13.616.3 ± 4.825.1 ± 13.4
    P-value (difference across studies 4-6)-0.240.31<0.010.76
    P-value (adolescent vs. adult)-0.51<0.01<0.01<0.01
(B) Brand type among adolescent and adult smokers

Regular
Light
Ultra light
Uncoded
N (%)
N (%)
N (%)
N (%)
Adolescent smokers
Study 148 (51.1)38 (40.4)2 (2.1)6 (6.4)
Study 291 (55.2)68 (41.2)2 (1.2)4 (2.4)
Study 309 (64.3)5 (35.7)0
Pooled139 (50.9)115 (42.1)9 (3.3)10 (3.7)
P-value (difference across studies 1-3)<0.01
Adult smokers
Study 49 (18.4)20 (40.8)12 (24.5)8 (16.3)
Study 54 (9.3)28 (65.1)9 (20.9)2 (4.7)
Study 617 (44.7)13 (34.2)3 (7.9)5 (13.2)
Pooled30 (23.1)61 (46.9)24 (18.5)15 (11.5)
P-value (difference across studies 4-6)<0.01
P-value (adolescent vs. adult)<0.01