Determinants of SHS exposure at home and outside the home among participants (n=10 289)
| Characteristics | Categories | Total (n=9982) | Home | P value | Outside home | P value |
| Adjusted OR (95% CI) | Adjusted OR (95% CI) | |||||
| Age group | 12–14 | 2184 (96.8) | 1 | 0.010 | 1 | <0.001 |
| 15–17 | 5129 (97.0) | 1.07 (0.95 to 1.21) | 1.04 (0.80 to 1.35) | |||
| 18–20 | 2669 (97.1) | 1.20 (1.02 to 1.40) | 1.14 (0.83 to 1.56) | |||
| Gender | Boys | 4437 (97.1) | 1 | <0.001 | 1 | 0.890 |
| Girls | 5545 (96.1) | 1.34 (1.22 to 1.47) | 1.01 (0.81 to 1.26) | |||
| School type | SSS | 4380 (97.2) | 1 | <0.001 | 1 | 0.119 |
| UBS | 5602 (96.8) | 1.40 (1.25 to 1.57) | 0.80 (0.61 to 1.05) | |||
| School funding | Public | 7464 (97.2) | 1 | <0.001 | 1 | 0.121 |
| Grant aided | 991 (94.2) | 1.36 (1.17 to 1.58) | 0.59 (0.43 to 0.80) | |||
| Private | 1527 (98.1) | 0.80 (0.70 to 0.92) | 1.47 (1.00 to 2.17) | |||
| School locality | Rural | 2389 (97.3) | 1 | <0.001 | 1 | 0.360 |
| Urban | 7593 (96.9) | 0.71 (0.64 to 0.79) | 0.88 (0.67 to 1.15) | |||
| Religion | Muslim | 9277 (96.9) | 1 | 0.049 | 1 | 0.346 |
| Christian | 588 (97.6) | 1.22 (1.01 to 1.47) | 1.16 (0.69 to 1.95) | |||
| Other | 98 (95.1) | 1.35 (0.86 to 2.12) | 0.56 (0.24 to 1.32) | |||
| Father’s education | No education | 2326 (96.1) | 1 | 0.150 | 1 | <0.001 |
| Primary | 655 (97.1) | 0.95 (0.78 to 1.16) | 2.01 (1.24 to 3.26) | |||
| Secondary | 2063 (97.3) | 1.26 (1.09 to 1.45) | 2.36 (1.69 to 3.31) | |||
| Tertiary | 1827 (97.8) | 0.88 (0.75 to 1.04) | 3.46 (2.29 to 5.22) | |||
| Quranic/Arabic | 2033 (96.9) | 0.98 (0.85 to 1.14) | 2.49 (1.77 to 3.50) | |||
| Do not know | 1077 (97.0) | 1.14 (0.95 to 1.36) | 2.12 (1.39 to 3.23) | |||
| Mother’s education | No education | 2941 (97.3) | 1 | <0.001 | 1 | <0.001 |
| Primary | 1137 (97.3) | 1.38 (1.18 to 1.61) | 0.94 (0.62 to 1.43) | |||
| Secondary | 2176 (98.0) | 0.92 (0.81 to 1.04) | 0.75 (0.52 to 1.08) | |||
| Tertiary | 1009 (98.5) | 0.91 (0.77 to 1.07) | 0.41 (0.26 to 0.65) | |||
| Quranic/Arabic | 1676 (94.5) | 0.95 (0.83 to 1.08) | 0.30 (0.21 to 0.42) | |||
| Do not know | 1040 (96.2) | 0.83 (0.71 to 0.98) | 0.45 (0.30 to 0.69) | |||
| Living with parents | No | 7988 (96.8) | 1 | 0.001 | 1 | 0.008 |
| Yes | 1987 (97.9) | 0.83 (0.74 to 0.93) | 0.66 (0.49 to 0.89) | |||
| Smoking status | Non-smokers | 8309 (97.0) | 1 | <0.001 | 1 | 0.250 |
| Ever smokers | 1671 (97.2) | 1.63 (1.31 to 2.03) | 1.46 (0.76 to 2.82) | |||
| Smoking at home allowed | No | 7060 (96.7) | 1 | <0.001 | 1 | 0.524 |
| Sometimes | 1070 (98.6) | 2.29 (1.99 to 2.64) | 0.88 (0.62 to 1.25) | |||
| Yes | 1849 (97.0) | 2.73 (2.43 to 3.07) | 0.86 (0.65 to 1.14) | |||
| Family smoking | None | 7112 (96.5) | 1 | <0.001 | 1 | 0.060 |
| Mother | 270 (98.5) | 1.66 (1.27 to 2.18) | 2.64 (0.95 to 7.29) | |||
| Father | 1177 (98.1) | 3.16 (2.74 to 3.65) | 0.75 (0.54 to 1.04) | |||
| Sibling | 702 (97.7) | 1.76 (1.49 to 2.08) | 1.14 (0.72 to 1.81) | |||
| Others | 716 (98.2) | 2.09 (1.77 to 2.47) | 1.33 (0.80 to 2.21) | |||
| Number of friends who smoke | None | 6563 (96.6) | 1 | <0.001 | 1 | 0.062 |
| One | 653 (97.0) | 1.89 (1.58 to 2.26) | 1.11 (0.71 to 1.73) | |||
| Two | 344 (96.6) | 1.94 (1.52 to 2.47) | 1.14 (0.63 to 2.08) | |||
| Three or more | 743 (97.5) | 1.53 (1.28 to 1.82) | 1.39 (0.85 to 2.25) | |||
| Not sure | 1670 (98.2) | 1.13 (1.00 to 1.28) | 1.63 (1.15 to 2.30) | |||
| Sent to buy cigarettes | No | 5700 (98.0) | 1 | <0.001 | 1 | 0.001 |
| Yes | 4271 (95.7) | 1.98 (1.80 to 2.18) | 1.42 (1.14 to 1.77) | |||
| Ban at enclosed public places | No | 5638 (97.8) | 1 | <0.001 | 1 | 0.191 |
| Yes | 4336 (95.9) | 1.22 (1.09 to 1.37) | 1.19 (0.91 to 1.55) | |||
| Ban at outdoor public places | No | 5713 (97.6) | 1 | 0.024 | 1 | 0.760 |
| Yes | 4259 (96.2) | 0.88 (0.78 to 0.98) | 1.04 (0.80 to 1.35) |
SHS, secondhand smoke; SSS, senior secondary schools; UBS, upper basic schools.