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Relationship between circadian salivary melatonin levels and sleep–wake behavior in infants
Author(s) -
Shinohara Hitomi,
Kodama Hideya
Publication year - 2011
Publication title -
pediatrics international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.49
H-Index - 63
eISSN - 1442-200X
pISSN - 1328-8067
DOI - 10.1111/j.1442-200x.2010.03186.x
Subject(s) - melatonin , morning , evening , circadian rhythm , medicine , saliva , endocrinology , sleep (system call) , noon , polysomnography , apnea , physics , astronomy , computer science , operating system
Background: There have been calls for more aggressive intervention for infants with failure in development of a sleep–wake rhythm. If development of the ‘biological clock’ in infants can be assessed by measuring melatonin, this may provide a useful indicator of the sleep–wake rhythm development. Thus, we investigated relationship between circadian salivary melatonin concentrations and sleep–wake behavioral parameters in infants. Methods: Sixty‐seven mothers who had infants aged 3–15 months were requested to record sleep–wake behavior of their baby for 2 days, and to collect their baby's saliva four times daily in the morning (06:00–09:00 h), noon (11:00–13:00 h), evening (16:00–18:00 h), and night (19:00–22:00 h) for measurement of melatonin concentrations by ELISA. Results: The mean melatonin concentrations of the saliva were: morning 40 ± 4 pg/mL, noon 14 ± 3 pg/mL, evening 15 ± 3 pg/mL, and night 23 ± 4 pg/mL. The melatonin concentrations, at each measurement point, were highest in infants aged 3–5 months, and decreased as age increased. Morning melatonin concentrations showed a negative correlation with nocturnal sleep duration ( P < 0.05). Increased morning concentrations were related to early waking time ( P < 0.05). In infants with open air baths on most days, evening and night melatonin concentrations were significantly lower ( P < 0.05). Conclusion: Salivary melatonin concentrations in infants between 06:00 and 22:00 decreased by age, and elevation of morning values may indicate an immature sleep–wake rhythm. Frequent open air baths may contribute to decreased melatonin levels.