6-SULFATOXYMELATONIN EXCRETION AND SELF-REPORTED SLEEP IN GOOD SLEEPING CONTROLS AND 55-80-YEAR-OLD INSOMNIACS

The pineal hormone melatonin is thought to play a role in sleep initia tion and maintenance. This was examined in a large sample of good slee ping controls (n = 52) and sleep maintenance insomniacs (n = 56), aged 55-80 y. Subjects collected 5 d of self-reported sleep diary measures , and 12-h urine samples (08.00-20.00 and 20.00-08.00 h) for analysis of the urinary melatonin metabolite, 6-sulphatoxymelatonin (aMT.6S). I nsomniacs reported a significantly greater amount of wake after sleep onset, less sleep in total, less efficient sleep and poorer quality sl eep compared to controls. However, no significant differences in melat onin excretion were observed between controls and insomniacs, with bot h groups showing similar mean (SEM) 12-h night-time [30.9 (2.9) vs. 30 .6 (3.3) nmoles, respectively] as well as 24-h total [38.7 (3.4) vs. 3 6.7 (3.8)] aMT.6S excretion levels. No significant correlations were o bserved with any sleep parameters nor any effects of medication (anti- inflammatory agents, hormone replacement therapy, and an undifferentia ted group of medications). The present results do not support a simple relationship between total melatonin production and self-reported sle ep quality and duration in the aged.