Figure 2
From: Effects of atopy and rhinitis on exhaled nitric oxide values - a systematic review
Visualization of summaries of FeNO comparisons. Groups with overlapping circles showed similar FeNO values. The radius of each circle is proportional to the number of articles measuring FeNO in each group. Upper limit of normal FeNO range was based on previous reports on children [21] and adults' [20] FeNO values. Atopic was defined as presence of allergic sensitization without asthma and without rhinitis.