title: Prenatal exposure to maternal bereavement and offspring psoriasis: a Danish nationwide cohort study.
abstract: BACKGROUND
  Prenatal stress may alter immune competence of the fetus. Limited data exist on the role of antenatal stress in psoriasis development.
  
  
  OBJECTIVE
  To investigate whether prenatal exposure to maternal bereavement increases the risk of offspring psoriasis.
  
  
  METHODS
  This register-based cohort study included 1 811 917 live singletons born from 1978 to 2008 in Denmark. The children were assigned to the bereaved group if their mothers lost a child, partner/spouse, parent or sibling during pregnancy or up to 12 months before pregnancy. Follow-up started at the date of birth and ended at the date of first hospital treatment for psoriasis or a prescription redeemed for topical vitamin D derivatives (often used to treat psoriasis), emigration, death or 31 December 2010, whichever came first. We evaluated the hazard ratio (HR) of psoriasis in bereaved children using Cox proportional hazards regressions, compared with the nonbereaved group.
  
  
  RESULTS
  During 28 million person-years of follow-up, 7956 children were hospitalized or prescribed medications for psoriasis. By the age of 30 years, 1·54% [95% confidence interval (CI) 1·25-1·90%] of children from the bereaved group were diagnosed with psoriasis, compared with 1·34% (95% CI 1·30-1·38%) of nonbereaved children. Overall, prenatal exposure to maternal bereavement was not associated with risk of psoriasis in general (HR 1·05, 95% CI 0·91-1·20). However, children born to mothers who lost a partner/spouse or an older child had an increased risk of psoriasis (HR 1·33, 95% CI 1·02-1·73).
  
  
  CONCLUSIONS
  Prenatal exposure to the most stressful life event may contribute to the development and/or exacerbation of psoriasis.
authors.affiliation: The National Centre for Register-based Research, Aarhus University, Aarhus, Denmark.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, China.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.|Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA, U.S.A.
authors.forename: J
authors.initials: J
authors.lastname: Olsen
authors.affiliation: Section for Environmental and Occupational Medicine, Department of Public Health, Aarhus University, Aarhus, Denmark.|National Research Center for the Working Environment, Copenhagen, Denmark.
authors.forename: V
authors.initials: V
authors.lastname: Schlünssen
authors.affiliation: Section for Epidemiology, Department of Public Health, Aarhus University, Denmark.
authors.forename: N
authors.initials: N
authors.lastname: Momen
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D001601:Bereavement; D002648:Child; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008423:Maternal Age; D018811:Maternal Exposure / Q000706:statistics & numerical data*; D009035:Mothers / Q000523:psychology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000276:immunology; D011565:Psoriasis / Q000453:epidemiology* / Q000523:psychology; D012307:Risk Factors; D055815:Young Adult