Table 2

Multiple linear regression of ΔFEV1 in ml/year in 234 subjects with asthma based on a mean observation period of 10 years

VariableEstimate (ml/year)SEp value
SE, standard error of the estimate; ICS, inhaled corticosteroids.
The intercept represents the mean annual decline in a non-smoking asthmatic woman without wheezing who is not treated with ICS. The estimate for different variables represents the difference in the annual decline in FEV1 between those with and those without these characteristics (this means that heavy smokers have an additional decline in FEV1 of 22.5 ml/year whereas those treated with ICS have a 17.8 ml/year lower decline in FEV1).
Intercept149.55.7<0.001
Sex
Women0
Men5.65.60.319
Smoking
Non-smokers0
Starters16.617.10.333
Quitters8.67.60.259
Light smokers2.18.70.805
Heavy smokers22.57.30.002
Wheezing
No0
Yes−13.16.00.030
ICS
No0
Yes−17.87.10.013