Background: Assessment of airway hyperresponsiveness (AHR) to indirect bronchoconstrictor stimuli is a useful noninvasive tool in the evaluation of asthma and its treatment. We investigated the putative relationship in AHR between inhaled adenosine monophosphate and mannitol.
Methods: Fifteen mild-to-moderate atopic asthmatics were evaluated. On two separate screening days, the threshold AMP concentration and threshold mannitol dose to provoke a given fall in FEV1 were measured.
Results: For AMP PC20vs. mannitol PD15, the Pearsons correlation coefficient was 0.80, P < 0.001. For AMP PC15vs. mannitol PD15 and AMP PC10vs. mannitol PD10 corresponding values were 0.83, P < 0.001 and 0.68, P = 0.005.
Conclusions: There was a highly significant association between the threshold concentration of AMP and dose of mannitol causing a given fall in FEV1. Further studies are required to evaluate the relationship between inhaled mannitol and other surrogate inflammatory markers.