title: Diurnal cycle of salivary cortisol in older adult men and women with subjective complaints of memory deficits and/or depressive symptoms: relation to cognitive functioning.
abstract: In populations of young and older adults, it has been shown that individuals may be categorized into one of three diurnal subgroups when salivary cortisol levels are assessed over a 2-day period and compared for their consistency across days: a typical subgroup, a flat subgroup, and an inconsistent subgroup. Interestingly, recent studies have reported that the typical subgroup represents the majority of the young and older adult population, a finding that is difficult to reconcile with previous studies showing increased cortisol levels in older adults with depression or cognitive impairments. In order to assess whether a typical diurnal cortisol profile is representative across different subgroups of older adults, we assessed diurnal cortisol cycle representation in a sample of older adults with subjective complaints of depression and/or memory problems. Furthermore, given the robust relationship between cortisol and cognitive function, the present study examined the association between the three diurnal subgroups and cognitive performance. Forty-two older individuals were recruited on the basis of reporting subjective complaints of either memory problems and/or depressive mood. Participants were asked to sample their saliva over a 2-day period and were then asked to undergo a neuropsychological evaluation that taps into short-term memory, declarative memory and language. The results showed that 69% of the sample presented a Flat cycle of salivary cortisol over a 2-day period while 19% presented an inconsistent pattern and 12% presented a typical pattern. Participants in the flat subgroup were significantly impaired on letter verbal fluency. Furthermore, a relationship was found between diurnal cortisol subgroup representation and subjective complaint profile. These findings show that older adults with complaints of memory problems and/or depressive symptoms do not present the typical profile of the diurnal cortisol cycle, and they provide a preliminary view of how diurnal cortisol profile relates to cognitive function during human aging.
authors.affiliation: Centre for Studies on Human Stress, Douglas Hospital/McGill University, Montreal, Quebec, Canada, H4H 1R3.
authors.forename: Alexandra J
authors.initials: AJ
authors.lastname: Fiocco
authors.forename: Nathalie
authors.initials: N
authors.lastname: Wan
authors.forename: Nicole
authors.initials: N
authors.lastname: Weekes
authors.forename: Heather
authors.initials: H
authors.lastname: Pim
authors.forename: Sonia J
authors.initials: SJ
authors.lastname: Lupien
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000032:analysis; D002940:Circadian Rhythm; D003071:Cognition; D003863:Depression / Q000523:psychology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008569:Memory Disorders / Q000523:psychology*; D008875:Middle Aged; D012463:Saliva / Q000378:metabolism*; D013060:Speech; D013315:Stress, Psychological; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D006854:Hydrocortisone