Comparison 3. Measures of airway inflammation.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Dose of histamine causing 20% fall in FEV1 (PD20)	1	34	Mean Difference (IV, Fixed, 95% CI)	0.08 [‐0.07, 0.23]
2 Exhaled Nitric Oxide ( crossover)	1		WMD (Fixed, 95% CI)	‐5.39 [‐5.78, ‐5.00]
2.1 Exhaled Nitric Oxide ( crossover) BDP 50mcg vs placebo	1		WMD (Fixed, 95% CI)	‐5.0 [‐7.90, ‐2.10]
2.2 Exhaled Nitric Oxide ( crossover) BDP 100mcg vs placebo	1		WMD (Fixed, 95% CI)	‐5.4 [‐5.79, ‐5.01]