Disorder of the saliva melatonin circadian rhythm in patients with Meniere's disease

Objective - Stress is involved in the development of symptoms of Meniere's disease (MD). Stress-related disease has been reported to be associated with disorders in the circadian rhythm of melatonin (MEL) which regulates that rhythm. We therefore investigated MEL circadian rhythm of patients with MD. Patients and methods - A comparison of 13 MD patients was made with age-matched controls. Saliva samples were collected every 3 h. A statistical analysis of the circadian rhythm of saliva MEL was performed for a circadian rhythm by the fit of a 24- and 12-h composite cosine model. In addition, we assessed the stress and depression status of the two groups. Results - The rhythmic amplitude of MEL in the MD group was significantly lower than that in the control group (P < 0.05). The acrophase in the MD group was significantly earlier than that in the control group (P < 0.05). MD patients had significantly higher stress score and depression score than control subjects (P < 0.05). The amplitude in MD patients had no significant correlation with their otologic clinical data. Conclusion - These results suggest that MD patients have a MEL deficiency, which is related to their stress and depression status rather than the otologic pathological status of MD.