title: Socioeconomic status in children is associated with hair cortisol levels as a biological measure of chronic stress.
abstract: BACKGROUND
  Low socioeconomic status (SES) may be associated with a high risk of lifestyle-related diseases such as cardiovascular diseases. There is a strong association between parental SES, stress and indicators of child health and adult health outcome. The exact mechanisms underlying this association have not yet been fully clarified. Low SES may be associated with chronic stress, which may lead to activation of the hypothalamic-pituitary-adrenal (HPA)-axis, resulting in a higher circulating level of the stress hormone cortisol. Therefore, chronic stress may mediate the association between low SES and elevated cortisol levels and its adverse outcomes.
  
  
  OBJECTIVE
  We investigated whether SES was associated with a chronic measure of cortisol exposure in a child population.
  
  
  METHODS
  Cortisol and cortisone were measured in scalp hair in 270 children and adolescents, aged 4-18 years, enrolled through school visits. Neighborhood level SES was based on a score developed by the Netherlands Institute for Social Research using postal codes, and this includes neighborhood measures of income education and unemployment. Maternal and paternal education level were used as indicators of family SES.
  
  
  RESULTS
  Neighborhood level socioeconomic status score was significantly associated with hair cortisol (β=-0.103, p=0.007, 95%CI [-0.179, -0.028]) and hair cortisone (β=-0.091, p=0.023, 95%CI [-0.167, -0.015]), adjusted for age and sex. Additionally, hair cortisol was significantly correlated with maternal education level and hair cortisone was significantly correlated with paternal education level.
  
  
  CONCLUSIONS
  The results of our study suggest that the widely shown association between low family SES and adverse child health outcomes may be mediated by chronic stress, given the chronically higher levels of cortisol in children and adolescents in families with low SES. It is especially notable that the association between SES and cortisol was already found in children of young age as this can have major consequences, such as increased risk of cardio metabolic diseases in later life.
authors.affiliation: Department of Pediatrics, Division of Endocrinology, Sophia Children's Hospital, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: j.vliegenthart@erasmusmc.nl.
authors.forename: J
authors.initials: J
authors.lastname: Vliegenthart
authors.affiliation: Department of Pediatrics, Division of Endocrinology, Sophia Children's Hospital, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands; Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: g.noppe@erasmusmc.nl.
authors.forename: G
authors.initials: G
authors.lastname: Noppe
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: e.vanrossum@erasmusmc.nl.
authors.forename: E F C
authors.initials: EF
authors.lastname: van Rossum
authors.affiliation: Department of Internal Medicine, Division of Endocrinology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: f.koper@erasmusmc.nl.
authors.forename: J W
authors.initials: JW
authors.lastname: Koper
authors.affiliation: Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: h.raat@erasmusmc.nl.
authors.forename: H
authors.initials: H
authors.lastname: Raat
authors.affiliation: Department of Pediatrics, Division of Endocrinology, Sophia Children's Hospital, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Electronic address: e.l.t.vandenakker@erasmusmc.nl.
authors.forename: E L T
authors.initials: EL
authors.lastname: van den Akker
mesh_terms: D000293:Adolescent; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003348:Cortisone / Q000378:metabolism; D005190:Family; D005260:Female; D006197:Hair / Q000378:metabolism*; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D007182:Income; D008297:Male; D009426:Netherlands; D010913:Pituitary-Adrenal System / Q000378:metabolism; D012111:Residence Characteristics; D012307:Risk Factors; D012923:Social Class; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D003348:Cortisone; D006854:Hydrocortisone
keywords: Children; Cortisol; SES; Scalp hair; Stress