declining melatonin levels and older people how old is old objectives the purpose of this study was to investigate whether melatonin levels in older cohorts within the aged population were significantly lower than in younger aged individuals and hence point to a possible confound in crosssectional studies which group individuals over 55 in one categorysetting and design melatonin levels of 35 north queensland residents over 55 years of age living in an agedcare facility a retirement village or the general community were compared across three age groupsmethods subjects were ten 5665 year olds eighteen 6675 year olds and seven over75 year olds information was obtained on sleep awakening medical conditions and medications with subsequent exclusion of those with known medical conditions andor medications melatonin was collected by salivary samples at 2200 hours and concentrations were determined by immunoassayresults mean melatonin levels were significantly lower p03 in the oldest over 75 yrs group compared to the youngest 5665 yrs groupmain findings the results of this preliminary study indicate that within the older population melatonin levels appear to decline significantly with ageconclusions future studies of melatonin and ageing may benefit from a longitudinal approach with older subjects sampled across time