Table 1

Prevalence (%) of asthma, wheeze, environmental tobacco smoke (ETS) exposure at age 7–8 and 16–17 years, and personal smoking habits at age 16–17 years

Age 7–8 yearsAge 16–17 yearsDifference by age p value
Boys (n=1416)Girls (n=1389)Difference by gender p valueBoys (n=1416)Girls (n=1389)Difference by gender p value
Outcome variables
Physician-diagnosed asthma7.54.20.00113.613.00.680<0.001
Current asthma6.94.00.0018.910.90.0800.012
Ever wheeze24.817.50.00121.926.10.010<0.001
Current wheeze11.48.30.00716.524.80.001<0.001
Exposure to tobacco smoke
In utero exposure23.124.30.439
Current maternal ETS27.530.20.26421.625.40.018<0.001
Current paternal ETS20.122.70.11018.419.10.6190.016
Continuous ETS mother12.815.60.031
Continuous ETS father6.47.00.505
Smoking habits
 Occasional smokers8.89.60.493
 Daily smokers5.711.4<0.001