title: Self Reported Childhood Difficulties, Adult Multimorbidity and Allostatic Load. A Cross-Sectional Analysis of the Norwegian HUNT Study.
abstract: BACKGROUND
  Multimorbidity receives increasing scientific attention. So does the detrimental health impact of adverse childhood experiences (ACE). Aetiological pathways from ACE to complex disease burdens are under investigation. In this context, the concept of allostatic overload is relevant, denoting the link between chronic detrimental stress, widespread biological perturbations and disease development. This study aimed to explore associations between self-reported childhood quality, biological perturbations and multimorbidity in adulthood.
  
  
  METHODS
  We included 37 612 participants, 30-69 years, from the Nord-Trøndelag Health Study, HUNT3 (2006-8). Twenty one chronic diseases, twelve biological parameters associated with allostatic load and four behavioural factors were analysed. Participants were categorised according to the self-reported quality of their childhood, as reflected in one question, alternatives ranging from 'very good' to 'very difficult'. The association between childhood quality, behavioural patterns, allostatic load and multimorbidity was compared between groups.
  
  
  RESULTS
  Overall, 85.4% of participants reported a 'good' or 'very good' childhood; 10.6% average, 3.3% 'difficult' and 0.8% 'very difficult'. Childhood difficulties were reported more often among women, smokers, individuals with sleep problems, less physical activity and lower education. In total, 44.8% of participants with a very good childhood had multimorbidity compared to 77.1% of those with a very difficult childhood (Odds ratio: 5.08; 95% CI: 3.63-7.11). Prevalences of individual diseases also differed significantly according to childhood quality; all but two (cancer and hypertension) showed a significantly higher prevalence (p<0.05) as childhood was categorised as more difficult. Eight of the 12 allostatic parameters differed significantly between childhood groups.
  
  
  CONCLUSIONS
  We found a general, graded association between self-reported childhood difficulties on the one hand and multimorbidity, individual disease burden and biological perturbations on the other. The finding is in accordance with previous research which conceptualises allostatic overload as an important route by which childhood adversities become biologically embodied.
authors.affiliation: Department of Family Medicine, University of Iceland and Primary Health Care of the Capital Area, Reykjavik, Iceland; General Practice Research Unit, Department of Public Health and General Practice, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Margret Olafia
authors.initials: MO
authors.lastname: Tomasdottir
authors.affiliation: Department of Family Medicine, University of Iceland and Primary Health Care of the Capital Area, Reykjavik, Iceland; General Practice Research Unit, Department of Public Health and General Practice, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Johann Agust
authors.initials: JA
authors.lastname: Sigurdsson
authors.affiliation: General Practice Research Unit, Department of Public Health and General Practice, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Halfdan
authors.initials: H
authors.lastname: Petursson
authors.affiliation: General Practice Research Unit, Department of Public Health and General Practice, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of General Practice, UiT The Arctic University, Tromsø, Norway.
authors.forename: Anna Luise
authors.initials: AL
authors.lastname: Kirkengen
authors.affiliation: HUNT Research Centre, Department of Public Health and General Practice, Norwegian University of Science and Technology (NTNU), Levanger, Norway.
authors.forename: Steinar
authors.initials: S
authors.lastname: Krokstad
authors.affiliation: Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York, United States of America.
authors.forename: Bruce
authors.initials: B
authors.lastname: McEwen
authors.affiliation: General Practice Research Unit, Department of Public Health and General Practice, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Irene
authors.initials: I
authors.lastname: Hetlevik
authors.affiliation: General Practice Research Unit, Department of Public Health and General Practice, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
authors.forename: Linn
authors.initials: L
authors.lastname: Getz
mesh_terms: D000328:Adult; D000368:Aged; D052636:Allostasis; D002648:Child; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008016:Life Change Events; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D057566:Self Report; D012959:Socioeconomic Factors