Adjusted ORs for Age of Starting Smoking Regularly for Daily Smokers With and Without Asthma and Stratified According to Gender*

Age of Starting Regular Smokingn (Asthma/Controls)Test for Asthma-Gender Interaction (P)AllGirlsBoys
OR95% CIOR95% CIOR95% CI
14 y89/721.3031.230.95–1.601.341.00–1.810.950.56–1.65
15 y96/912.2010.960.74–1.230.860.63––1.90
16 y or older98/1097.0450.800.62–1.020.940.70–1.250.520.31–0.85
  • * We adjusted in both logistic regression analysis and tests for trend for gender, age (1-year categories), family type, parental smoking pattern and parental job, BMI, and exercise categorized as shown in Table 1. Statistically significant tests for asthma-gender interaction are presented in the results. Information on age of starting smoking regularly was missing for 2 pupils with asthma and 9 pupils without asthma.