title: Assessing the contributions of childhood maltreatment subtypes and depression case-control status on telomere length reveals a specific role of physical neglect.
abstract: Studies have provided evidence that both childhood maltreatment and depressive disorders are associated with shortened telomere lengths. However, as childhood maltreatment is a risk factor for depression, it remains unclear whether this may be driving shortened telomere lengths observed amongst depressed patients. Furthermore, it's unclear if the effects of maltreatment on telomere length shortening are more pervasive amongst depressed patients relative to controls, and consequently whether biological ageing may contribute to depression's pathophysiology. The current study assesses the effects of childhood maltreatment, depression case/control status, and the interactive effect of both childhood maltreatment and depression case/control status on relative telomere length (RTL).
  
  
  
  DNA samples from 80 depressed subjects and 100 control subjects were utilized from a U.K. sample (ages 20-84), with childhood trauma questionnaire data available for all participants. RTL was quantified using quantitative polymerase chain reactions. Univariate linear regression analyses were used to assess the effects of depression status, childhood maltreatment and depression by childhood maltreatment interactions on RTL. The false discovery rate (q<0.05) was used for multiple testing correction.
  
  
  
  Analysis of depression case/control status showed no significant main effect on RTL. Four subtypes of childhood maltreatment also demonstrated no significant main effect on RTL, however a history of physical neglect did significantly predict shorter RTL in adulthood (F(1, 174)=7.559, p=0.007, q=0.042, Variance Explained=4.2%), which was independent of case/control status. RTL was further predicted by severity of physical neglect, with the greatest differences observed in older maltreated individuals (>50 years old). There were no significant depression case/control status by childhood maltreatment interactions.
  
  
  
  A relatively small sample limited our power to detect interaction effects, and we were unable to consider depression chronicity or recurrence.
  
  
  
  Shortened RTL was specifically associated with childhood physical neglect, but not the other subtypes of maltreatment or depression case/control status. Our results suggest that the telomere-eroding effects of physical neglect may represent a biological mechanism important in increasing risk for ageing-related disorders. As physical neglect is more frequent amongst depressed cases generally, it may also represent a confounding factor driving previous associations between shorter RTL and depression case status.
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, UK.
authors.forename: John
authors.initials: J
authors.lastname: Vincent
authors.affiliation: Department of Biosciences, University of Helsinki, Helsinki, Finland.
authors.forename: Iiris
authors.initials: I
authors.lastname: Hovatta
authors.affiliation: King's College London, Health Service & Population Research, Institute of Psychiatry, Psychology & Neuroscience, London, UK.
authors.forename: Souci
authors.initials: S
authors.lastname: Frissa
authors.affiliation: King's College London, Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, London, UK; University of Liverpool, Department of Psychological Sciences, Liverpool, UK.
authors.forename: Laura
authors.initials: L
authors.lastname: Goodwin
authors.affiliation: King's College London, Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, London, UK; National Institute for Health Research Biomedical Research Centre for Mental Health, Institute of Psychiatry, Psychology and Neuroscience at the Maudsley Hospital and King's College London, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Hotopf
authors.affiliation: King's College London, Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, London, UK.
authors.forename: Stephani L
authors.initials: SL
authors.lastname: Hatch
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, UK; National Institute for Health Research Biomedical Research Centre for Mental Health, Institute of Psychiatry, Psychology and Neuroscience at the Maudsley Hospital and King's College London, UK.
authors.forename: Gerome
authors.initials: G
authors.lastname: Breen
authors.affiliation: King's College London, MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology & Neuroscience, London, UK. Electronic address: timothy.1.powell@kcl.ac.uk.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Powell
mesh_terms: D000328:Adult; D054523:Adult Survivors of Child Abuse; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002649:Child Abuse; D004247:DNA / Q000302:isolation & purification; D003863:Depression; D003866:Depressive Disorder / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012307:Risk Factors; D011795:Surveys and Questionnaires; D016615:Telomere / Q000235:genetics / Q000648:ultrastructure*; D059506:Telomere Shortening; D055815:Young Adult
chemical_list: D004247:DNA