Single-breath exhaled nitric oxide (SB-FENO) concentrations measured at age 3 years were significantly greater among subjects with persistence of wheezing at age 3 years (closed triangles) as compared to subjects with resolution of wheezing (open circles), both among all subjects (panel A.; 30.8 ppb vs. 20.7 ppb, p=0.048) and when subjects using inhaled corticosteroids on a sustained basis were excluded (panel B.; 33.5 ppb vs. 20.7 ppb, p=0.036). SB-FENO concentrations were also significantly higher among subjects who experienced exacerbations prior to age 3 years (closed triangles) then among subjects who did not experience exacerbations prior to age 3 years (open circles), both among all subjects (panel C.; 32.9 ppb vs. 22.6 ppb, p=0.04) and when subjects using inhaled corticosteroids on a sustained basis were excluded (panel D.; 36.9 ppb vs. 22.2 ppb, p=0.036). All analyses conducted using unpaired t tests.