Individual differences in the amount and timing of salivary melatonin secretion.
The aim of this study was to examine individual differences in a large sample of complete melatonin profiles not suppressed by light and search for possible associations between the amount and timing of melatonin secretion and a multitude of lifestyle variables. The melatonin profiles were derived from saliva samples collected every 30 minutes in dim light from 85 healthy women and 85 healthy men aged 18-45 years. There was a large individual variability in the amount of melatonin secreted with peak values ranging from 2 to 84 pg/ml. The onset of melatonin secretion ranged from 18:13 to 00:26 hours. The use of hormonal birth control, reduced levels of employment, a smaller number of days on a fixed sleep schedule, increased day length and lower weight were associated with an increased amplitude of melatonin secretion. The use of hormonal birth control, contact lenses, a younger age, and lower ratings of mania and paranoia were associated with a longer duration of melatonin secretion. An earlier occurrence of the onset of melatonin secretion was associated with an earlier wake time, more morningness and the absence of a bed partner. Lifestyle and behavioral variables were only able to explain about 15% of the individual variability in the amount of melatonin secretion, which is likely because of a substantial genetic influence on the levels of melatonin secretion.
Burgess
Helen J
HJ
Biological Rhythms Research Laboratory, Department of Behavioral Sciences, Rush University Medical Center, Chicago, Illinois, United States of America. Helen_J_Burgess@rush.edu
Fogg
Louis F
LF
D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D003624:Darkness; D005260:Female; D006801:Humans; D007700:Kinetics; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D008875:Middle Aged; D044469:Racial Groups; D012016:Reference Values; D012463:Saliva / Q000378:metabolism*; D012890:Sleep; D012959:Socioeconomic Factors; D014851:Wakefulness
D008550:Melatonin