Determinants of bronchodilator responsiveness in forced expiratory volume in one second as % pre-bronchodilator value [%ΔFEV1i] –results from univariate and multivariate analyses of the whole cohort.

*Standard estimates allow comparison between variables with different units. It is the expected change in bronchodilator response per 1 SD increase in the variable. After multivariate correction for confounding variables the ‘most powerful’ effect on BDRFEV1 is doctor diagnosis of current-asthma, followed by age, ever-smoking, use of respiratory drugs (any medication for breathing including nasal decongestant), and gender.These values are adjusted for all corivariates including site and for the proportion of Caucasian population in each site.