Table 1.
Characteristics of the study subjects (n = 667).
| Variable | Total | School 1 (n = 249) | School 2 (n = 254) | School 3 (n = 164) | |||||
|---|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | ||
| Gender | |||||||||
| Male | 455 | 68.2 | 192 | 77.1 | 169 | 66.5 | 94 | 57.3 | |
| Female | 212 | 31.8 | 57 | 22.9 | 85 | 33.5 | 70 | 42.7 | |
| Age (year) | |||||||||
| 15 | 215 | 32.2 | 81 | 32.5 | 74 | 29.1 | 60 | 36.6 | |
| 16 | 239 | 35.8 | 92 | 36.9 | 81 | 31.9 | 66 | 40.2 | |
| 17 | 188 | 28.2 | 70 | 28.1 | 83 | 32.7 | 35 | 21.3 | |
| 18 | 25 | 3.7 | 6 | 2.4 | 16 | 6.3 | 3 | 1.8 | |
| Living at current address (year) | |||||||||
| 3–5 | 420 | 62.9 | 169 | 67.9 | 190 | 74.8 | 61 | 37.2 | |
| 6–10 | 98 | 14.7 | 28 | 11.2 | 30 | 11.8 | 40 | 24.4 | |
| 11–15 | 121 | 18.2 | 36 | 14.5 | 32 | 12.6 | 53 | 32.3 | |
| ≥16 | 28 | 4.2 | 16 | 6 | 2 | 0.8 | 10 | 6.1 | |
| Mother’s education | |||||||||
| ≤Primary school | 250 | 37.5 | 134 | 53.8 | 60 | 23.6 | 56 | 34.1 | |
| Middle school | 103 | 15.4 | 55 | 22.1 | 24 | 9.5 | 24 | 14.6 | |
| High school | 162 | 24.3 | 42 | 16.9 | 68 | 26.8 | 52 | 31.7 | |
| University | 152 | 22.8 | 18 | 7.2 | 102 | 40.1 | 32 | 19.6 | |
| Father’s education | |||||||||
| ≤Primary school | 118 | 17.7 | 75 | 30.1 | 14 | 5.5 | 29 | 17.6 | |
| Middle school | 82 | 12.3 | 57 | 22.9 | 13 | 5.1 | 12 | 7.3 | |
| High school | 204 | 30.6 | 82 | 32.9 | 65 | 25.6 | 57 | 34.8 | |
| University | 263 | 39.4 | 35 | 14.1 | 162 | 63.8 | 66 | 40.3 | |
| Mother’s job | |||||||||
| Housewife | 473 | 70.9 | 221 | 88.8 | 136 | 53.5 | 116 | 70.7 | |
| Retired | 52 | 7.8 | 7 | 2.8 | 32 | 12.6 | 13 | 7.9 | |
| Blue collar worker | 14 | 2.1 | 7 | 2.8 | 0 | 0 | 7 | 4.3 | |
| White collar worker | 112 | 16.8 | 14 | 5.6 | 81 | 31.9 | 17 | 10.4 | |
| Other | 16 | 2.4 | 0 | 0 | 5 | 2.0 | 11 | 6.7 | |
| Father’s job | |||||||||
| Retired | 126 | 18.9 | 39 | 15.7 | 48 | 18.9 | 39 | 23.8 | |
| Blue collar worker | 128 | 19.2 | 83 | 33.3 | 19 | 7.5 | 26 | 15.9 | |
| White collar worker | 98 | 14.7 | 51 | 20.5 | 27 | 10.6 | 20 | 12.2 | |
| Own work | 25 | 3.7 | 12 | 4.8 | 11 | 4.3 | 2 | 1.2 | |
| Farmer | 175 | 26.2 | 48 | 19.3 | 95 | 37.4 | 32 | 19.5 | |
| Driver | 17 | 2.5 | 12 | 4.8 | 1 | 10.4 | 4 | 2.4 | |
| Other | 98 | 14.6 | 4 | 1.6 | 53 | 20.9 | 41 | 25.0 | |
| Student | |||||||||
| Yes works | 14 | 2.1 | 7 | 2.8 | 0 | 0.0 | 7 | 2.3 | |
| No doesn’t work | 653 | 97.9 | 242 | 97.2 | 254 | 100 | 157 | 95.7 | |
| Monthly income | |||||||||
| Low | 68 | 10.0 | 56 | 22.5 | 4 | 1.6 | 8 | 4.9 | |
| Medium | 494 | 74.2 | 186 | 74.7 | 178 | 70.1 | 130 | 79.3 | |
| High | 105 | 15.7 | 7 | 2.8 | 72 | 28.3 | 26 | 15.9 | |
| Own room | |||||||||
| There is | 521 | 78.1 | 198 | 79.5 | 181 | 71.3 | 142 | 86.6 | |
| There is not | 146 | 21.9 | 51 | 20.5 | 73 | 28.7 | 22 | 13.4 | |
| Smoking status | |||||||||
| Current smoker | 84 | 12.6 | 61 | 24.5 | 7 | 2.8 | 16 | 9.8 | |
| Never smoked | 545 | 81.7 | 168 | 67.5 | 233 | 91.7 | 144 | 87.8 | |
| Ex smoker | 38 | 5.7 | 20 | 8.0 | 14 | 5.5 | 4 | 2.4 | |
| Passive smoker | |||||||||
| Yes | 370 | 55.5 | 92 | 36.9 | 159 | 62.6 | 119 | 72.6 | |
| No | 297 | 44.5 | 157 | 63.1 | 95 | 37.4 | 45 | 27.4 | |
School 1: industrial zone; School 2: urban zone; School 3: rural zone.