Aim: To investigate the possible relationships between alterations in circadian rhythm of melatonin, cortisol and bronchial asthma.
Methods: Salivary melatonin and cortisol were measured simultaneously by radioimmunoassay in 10 mild intermittent or persistent patients, 11 moderate-to-severe persistent asthma patients, and 15 control subjects. Twelve salivary samples were collected in a series during a 24-h period in each subject.
Results: The results showed overall lower levels of salivary melatonin in asthma patients compared with control subject (P<0.01). The amplitude, peak-level, and baseline of salivary melatonin were significantly lower in mild intermittent or persistent (P<0.01, P<0.05) and moderate-to-severe persistent asthma patients (P<0.01) compared with control group. The 24-h mean level of salivary cortisol was greatly lower and the acrophase was markedly delayed in patients with mild intermittent or persistent asthma (P<0.01) and moderate-to-severe persistent asthma (P< 0.05, P<0.01) compared with control subject.
Conclusion: Disordered circadian rhythms of salivary melatonin and cortisol were found in asthma patients, which may be involved in the pathogenesis of bronchial asthma.