Background Sulfur mustard (SM) exposure causes respiratory disorders, progressive deterioration in lung function and mortality in injured victims and poor sleep quality is one of the most common problems among SM-exposed patients. Since melatonin has a critical role in regulation of sleep and awareness, this study aimed to evaluate the serum melatonin levels in SM-injured subjects.
Methods A total of 30 SM-exposed male patients and 10 controls was evaluated. Sleep quality was evaluated by the Pittsburgh Sleep Quality Index (PSQI); daytime sleepiness was measured by the Epworth Sleepiness Scale (ESS), and the risk of obstructive sleep apnoea was determined by the STOP-Bang questionnaire. Polysomnography (PSG) and pulmonary function tests (PFTs) were also available. Nocturnal serum melatonin levels were measured using an ELISA kit.
Results The mean of PSQI, ESS and STOP-Bang scores in patients (11.76±3.56, 12.6±3.03 and 5.03±1.09, respectively) were significantly (p<0.01) higher than those in the controls (2.78±0.83, 4.69±1.15 and 1.18±0.82, respectively). PFTs also showed declined respiratory quality in SM-patients. There was a significant difference regarding the PSG results between patients and controls (p<0.01). The mean of nocturnal serum melatonin levels in patients (29.78±19.31 pg/mL) was significantly (p=0.005) lower than that in the controls (78.53±34.41 pg/mL).
Conclusions Reduced nocturnal serum melatonin and respiratory disorders can be the reasons for poor sleep quality among these patients.
Trial registration number IRCT2015092924267N1, Pre-results.
- Nocturnal melatonin
- Sleep quality
- Sulfur mustard
- Chronic pulmonary problems
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Contributors This work was extracted from a part of a PhD thesis of SSM. SSM was involved in sample collection, study concept and design, laboratory research, interpreting the data analysis, manuscript writing and review, data acquisition and results interpretation; EV, MS and YP were involved with project supervision and manuscript review; and SP was involved in management of laboratory equipment. All the authors have read and approved the final version of the manuscript.
Funding All financial funds for this study were provided by the Chemical Injury Research Center, Baqiyatallah University of Medical Sciences.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Ethics Review Board of the Baqiyatallah University of Medical Sciences, Tehran, Iran (2014–2015) approved the study. All subjects signed an informed consent form and the procedures conformed to the guiding principles of the Declaration of Helsinki.
Provenance and peer review Not commissioned; externally peer reviewed.
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