ABSTRACT
Five adult asthmatics with nocturnal symptoms [mean FEV[1] 2.31 1;2 mean PD[20] histamine 1.5 unmoles], 5 asthmatics with no nocturnal symptoms [mean FEV[1] 1 2.97 1; mean PD[20] Histamine 3.7 umoles] and 5 non-asthmatic control subjects [mean FEV[1] 3.63 1; mean PD[20] histamine 78 umoles] were challenged with nebulised solutions of their own saliva or isotonic saline in a double blind crossover study to investigate whether the inhalation of saliva during sleep could cause nocturnal asthma. The maximum percent fall in FEV[1] with saliva was -26.6, -6.5 and -4.1 for the nocturnal, non-nocturnal and control groups respectively. The corresponding values for the maximum percent fall in FEV[1] with saline was -12.4, -5.5 and -3.6. The difference in maximum percent fall in FEV[1] with both saliva and saline was significant [p<0.01] for the nocturnal asthmatics when compared to the non-nocturnal asthmatics. These results lend support to the hypothesis that nocturnal symptoms in asthmatic patients may be triggered by inhalation of saliva during sleep