Mean age at initiation by current income Well below the median Below the median Around the median Above the median Well above the median Refused to answer (ANOVA p-value) by age at last education <16 16-19 20-25 >25 Missing (ANOVA p-value) by current age* 18-24 25-34 35-44 45-54 55+ (ANOVA p-value) 241 19.3 591 18.3 647 18.1 400 17.7 79 17.9 406 18.1 (p = 0.0025) 288 18.8 1052 18.0 713 18.2 229 18.3 82 17.3 (p = 0.0913) 184 419 16.4 380 17.0 391 17.0 743 17.6 (p < 0.0001) 49 18.5 114 17.8 111 18.4 79 18.4 14 20.0 94 17.3 (p = 0.0945) 21 20.9 165 18.2 214 18.0 19 17.6 42 17.2 (p = 0.0162) 30 76 16.9 61 17.2 74 16.8 179 17.7 (p = 0.0002) 41 20.3 144 17.9 144 17.6 107 17.4 11 19.6 68 17.8 (p = 0.0101) 89 17.9 278 18.0 112 17.8 30 18.3 6 14.3 (p = 0.9321) 50 110 16.4 102 17.2 78 17.0 129 17.6 (p < 0.0001) 88 18.7 143 18.3 113 18.3 41 18.6 4 22.8 83 19.3 (p = 0.4711) 104 19.7 175 18.1 140 18.3 50 18.8 3 19.4 (p = 0.0807) 30 92 16.3 74 17.1 87 17.3 136 17.9 (p < 0.0001) Oh et al. BMC Public Health 2010, 10:74 http://www.biomedcentral.com/1471-2458/10/74 Table 5 Mean age at smoking initiation by income, education, and age, weighted. All France Ireland Italy (n = 2364) (n = 461) (n = 515) (n = 472) n mean n mean n mean n mean *excluding those who initiated after the age of 24 (n = 245) Table 6 Linear regression of factors associated with age at smoking initiation. b (95% CI) Intercept 18.74 (18.20, 19.28) Country France - Ireland 0.22 (-0.38, 0.82) Italy 0.54 (-0.06, 1.14) Czech 1.79 (1.16, 2.41) Sweden -0.72 (-1.30, -0.14) Reasons for initiation* My friends smoked -1.02 (-1.42, -0.61) Smoking made me look more cool -1.69 (-2.15, -1.23) My friends approved of my smoking -0.36 (-1.11, 0.39) It helped me manage my stress 2.67 (1.88, 3.45) My family members smoked -0.20 (-0.98, 0.58) I was not worried about health effects 0.41 (-0.63, 1.45) I believed I could quit whenever I wanted to -0.65 (-1.69, 0.39) Tobacco advertising was attractive to me 0.67 (-0.79, 2.14) Weight concerns 0.45 (-1.08, 1.99) I was less depressed when I smoked 3.88 (2.33, 5.42) My parents did not mind that I smoked -0.95 (-3.27, 1.37) *Respondents could choose more than one reason for initiation. Those who gave each reason were compared with those who did not. p-value <0.0001 0.47 0.08 <0.0001 0.02 <0.0001 <0.0001 0.35 <0.0001 0.61 0.44 0.22 0.37 0.56 <0.0001 0.42 Czech Republic (n = 427) n mean 28 20.9 92 21.1 175 18.9 71 18.7 4 17.3 57 20.2 (p = 0.0077) 19 21.2 228 19.7 138 19.1 35 20.3 7 18.9 (p = 0.3701) 37 80 17.2 52 17.8 60 17.9 122 18.5 (p < 0.0001) Page 7 of 11 Sweden (n = 489) n mean 35 19.1 98 17.0 104 17.0 102 16.6 46 16.6 104 17.0 (p = 0.0566) 55 17.3 206 16.3 109 17.7 95 17.6 24 17.5 (p = 0.0071) 37 61 15.2 91 16.2 92 16.2 177 16.9 (p < 0.0001)