Table 2: Adjusted odds ratios and their 95% confidence intervals (CIs) for the association between sociodemographic and smoking-related variables with overall SHS exposure.

FactorOverall SHS exposure OR 95% CI
Not exposed

Age (in years)
School grade
Father’s education
 No formal education491081.00Reference
 Less than university37710200.760.67–0.98
 University or higher37512810.650.50–0.87
Mother’s education
 No formal education671621.00Reference
 Less than university38912060.820.66–1.17
 University or higher34510410.850.71–1.20
Family structure
 One or both parents75923601.00Reference
Smoking status
 Smoker or former smoker4365983.663.06–4.27
Parents smoking
 One or both are smokers3933924.954.15–5.90
Close friends smoking
 Some of them smoke5368573.713.09–4.33
Knowledge about harmful effects of smoking
Belief in harmful effects of SHS

Each variable is adjusted by the other variables in the table.