Fig 3. Development of z-scored measures of lung function and bronchial reactivity from 1 month to 13 years in children with transient asthma, children with persistent asthma, and children never developing asthma.

z-Scores for (A) forced expiratory volume (FEV_z), (B) maximal mid-expiratory flow (MMEF_z), (C) specific airway resistance (sRaw_z), and (D) provocative dose of methacholine (PD_z). Dashed lines represent 95% confidence intervals; grey triangles indicate timing of measurements.