title: Splitting hair for cortisol? Associations of socio-economic status, ethnicity, hair color, gender and other child characteristics with hair cortisol and cortisone.
abstract: The aim of this study was to examine associations of SES and ethnicity with hair cortisol and cortisone and to identify potential child and family characteristics that can assist in choosing covariates and potential confounders for analyses involving hair cortisol and cortisone concentrations. Hair samples were collected in 2484 6-year-old children from the Generation R Study, a prospective cohort in Rotterdam, the Netherlands. Measurements for cortisol and cortisone were used as the outcome in regression analyses. Predictors were SES, ethnicity, hair color and child characteristics such as birthweight, gestational age at birth, BMI, disease, allergy, and medication use. Lower family income, more children to be supported by this income, higher BMI and darker hair color were associated with higher hair cortisol and cortisone levels. Boys also showed higher levels. Ethnicity (Dutch and North European descent) was related to lower levels. High amounts of sun in the month of hair collection was related to higher levels of cortisone only. More recent hair washing was related to lower levels of cortisol and cortisone. Gestational age at birth, birth weight, age, medication use, hair washing frequency, educational level of the mother, marital status of the mother, disease and allergy were not associated with cortisol or cortisone levels. Our results serve as a starting point for choosing covariates and confounders in studies of substantive predictors or outcomes. Gender, BMI, income, the number of persons in a household, ethnicity, hair color and recency of hair washing are strongly suggested to take into account.
authors.affiliation: Centre for Child and Family Studies, Leiden University, Leiden, The Netherlands.
authors.forename: Ralph C A
authors.initials: RC
authors.lastname: Rippe
authors.affiliation: Department of Pediatrics, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Gerard
authors.initials: G
authors.lastname: Noppe
authors.affiliation: Centre for Child and Family Studies, Leiden University, Leiden, The Netherlands; The Generation R Study Group, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Child and Adolescent Psychiatry, Erasmus University Medical Center-Sophia Childreńs Hospital, Rotterdam, The Netherlands.
authors.forename: Dafna A
authors.initials: DA
authors.lastname: Windhorst
authors.affiliation: Department of Child and Adolescent Psychiatry, Erasmus University Medical Center-Sophia Childreńs Hospital, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Henning
authors.initials: H
authors.lastname: Tiemeier
authors.affiliation: Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Elisabeth F C
authors.initials: EF
authors.lastname: van Rossum
authors.affiliation: The Generation R Study Group, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands; Department of Pediatrics, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Vincent W V
authors.initials: VW
authors.lastname: Jaddoe
authors.affiliation: Department of Child and Adolescent Psychiatry, Erasmus University Medical Center-Sophia Childreńs Hospital, Rotterdam, The Netherlands.
authors.forename: Frank C
authors.initials: FC
authors.lastname: Verhulst
authors.affiliation: Centre for Child and Family Studies, Leiden University, Leiden, The Netherlands.
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Bakermans-Kranenburg
authors.affiliation: Centre for Child and Family Studies, Leiden University, Leiden, The Netherlands; School of Pedagogical and Educational Sciences, Erasmus University, Rotterdam, The Netherlands. Electronic address: vanijzen@fsw.leidenuniv.nl.
authors.forename: Marinus H
authors.initials: MH
authors.lastname: van IJzendoorn
authors.affiliation: Department of Pediatrics, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Erica L T
authors.initials: EL
authors.lastname: van den Akker
mesh_terms: D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003348:Cortisone / Q000032:analysis* / Q000378:metabolism; D005006:Ethnicity / Q000706:statistics & numerical data; D005260:Female; D006197:Hair / Q000737:chemistry* / Q000378:metabolism; D006200:Hair Color / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000378:metabolism; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D012737:Sex Factors; D012923:Social Class; D013315:Stress, Psychological / Q000208:ethnology / Q000378:metabolism
chemical_list: D003348:Cortisone; D006854:Hydrocortisone
keywords: Confounder; Cortisol; Cortisone; Covariate; Ethnicity; Generation R; Hair; SES