title: Associations between sociodemographic, sampling and health factors and various salivary cortisol indicators in a large sample without psychopathology.
abstract: BACKGROUND
  Cortisol levels are increasingly often assessed in large-scale psychosomatic research. Although determinants of different salivary cortisol indicators have been described, they have not yet been systematically studied within the same study with a large sample size. Sociodemographic, health and sampling-related determinants of salivary cortisol levels were examined in a sample without potential disturbances because of psychopathology.
  
  
  METHODS
  Using 491 respondents (mean age=43.0 years, 59.5% female) without lifetime psychiatric disorders from the Netherlands Study of Depression and Anxiety (NESDA), sociodemographic, sampling and health determinants of salivary cortisol levels were examined. Respondents collected seven salivary cortisol samples providing information about 1-h awakening cortisol, diurnal slope, evening cortisol and a dexamethasone (0.5mg) suppression test (DST).
  
  
  RESULTS
  Higher overall morning cortisol values were found for smokers, physically active persons, persons without cardiovascular disease, sampling on a working day or in a month with less daylight. In addition, the cortisol awakening response was significantly flattened for males, persons with cardiovascular disease, those with late awakening times and those with longer sleep duration. Diurnal slope was steeper in men, physically active persons, late awakeners, working persons, and season with less daylight. A higher evening cortisol level was associated with older age, smoking and season with more daylight. Cortisol suppression after dexamethasone ingestion was found to be less pronounced in smokers, less active persons and sampling on a weekday.
  
  
  CONCLUSIONS
  Sociodemographic variables (sex, age), sampling factors (awakening time, working day, sampling month, sleep duration) and health indicators (smoking, physical activity, cardiovascular disease) were shown to influence different features of salivary cortisol levels. Smoking had the most consistent effect on all cortisol variables. These factors should be considered in psychoneuroendocrinology research.
authors.affiliation: Department of Psychiatry, EMGO Institute for Health and Care Research, VU University Medical Center, A.J. Ernststraat 887, 1081 HL Amsterdam, The Netherlands.
authors.forename: Sophie A
authors.initials: SA
authors.lastname: Vreeburg
authors.forename: Boudewijn P
authors.initials: BP
authors.lastname: Kruijtzer
authors.forename: Johannes
authors.initials: J
authors.lastname: van Pelt
authors.forename: Richard
authors.initials: R
authors.lastname: van Dyck
authors.forename: Roel H
authors.initials: RH
authors.lastname: DeRijk
authors.forename: Witte J G
authors.initials: WJ
authors.lastname: Hoogendijk
authors.forename: Jan H
authors.initials: JH
authors.lastname: Smit
authors.forename: Frans G
authors.initials: FG
authors.lastname: Zitman
authors.forename: Brenda W J H
authors.initials: BW
authors.lastname: Penninx
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002940:Circadian Rhythm; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D006304:Health Status; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012107:Research Design; D012463:Saliva / Q000187:drug effects / Q000378:metabolism*; D012737:Sex Factors; D012959:Socioeconomic Factors; D013997:Time Factors; D014851:Wakefulness
chemical_list: D015415:Biomarkers; D003907:Dexamethasone; D006854:Hydrocortisone