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Association of etiological factors across the extreme end and continuous variation in disordered eating in female Swedish twins

Dinkler, Lisa ; Taylor, Mark J. ; Råstam, Maria LU ; Hadjikhani, Nouchine ; Bulik, Cynthia M. ; Lichtenstein, Paul ; Gillberg, Christopher and Lundström, Sebastian LU (2019) In Psychological Medicine
Abstract

BackgroundAccumulating evidence suggests that many psychiatric disorders etiologically represent the extreme end of dimensionally distributed features rather than distinct entities. The extent to which this applies to eating disorders (EDs) is unknown.MethodsWe investigated if there is similar etiology in (a) the continuous distribution of the Eating Disorder Inventory-2 (EDI-2), (b) the extremes of EDI-2 score, and (c) registered ED diagnoses, in 1481 female twin pairs at age 18 years (born 1992-1999). EDI-2 scores were self-reported at age 18. ED diagnoses were identified through the Swedish National Patient Register, parent-reported treatment and/or self-reported purging behavior of a frequency and duration consistent with DSM-IV... (More)

BackgroundAccumulating evidence suggests that many psychiatric disorders etiologically represent the extreme end of dimensionally distributed features rather than distinct entities. The extent to which this applies to eating disorders (EDs) is unknown.MethodsWe investigated if there is similar etiology in (a) the continuous distribution of the Eating Disorder Inventory-2 (EDI-2), (b) the extremes of EDI-2 score, and (c) registered ED diagnoses, in 1481 female twin pairs at age 18 years (born 1992-1999). EDI-2 scores were self-reported at age 18. ED diagnoses were identified through the Swedish National Patient Register, parent-reported treatment and/or self-reported purging behavior of a frequency and duration consistent with DSM-IV criteria. We differentiated between anorexia nervosa (AN) and other EDs.ResultsThe heritability of the EDI-2 score was 0.65 (95% CI 0.61-0.68). The group heritabilities in DeFries-Fulker extremes analyses were consistent over different percentile-based extreme groups [0.59 (95% CI 0.37-0.81) to 0.65 (95% CI 0.55-0.75)]. Similarly, the heritabilities in liability threshold models were consistent over different levels of severity. In joint categorical-continuous models, the twin-based genetic correlation was 0.52 (95% CI 0.39-0.65) between EDI-2 score and diagnoses of other EDs, and 0.26 (95% CI 0.08-0.42) between EDI-2 score and diagnoses of AN. The non-shared environmental correlations were 0.52 (95% CI 0.32-0.70) and 0.60 (95% CI 0.38-0.79), respectively.ConclusionsOur findings suggest that some EDs can partly be conceptualized as the extreme manifestation of continuously distributed ED features. AN, however, might be more distinctly genetically demarcated from ED features in the general population than other EDs.

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organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Adolescence, anorexia nervosa, eating disorders, quantitative genetics, twin study
in
Psychological Medicine
publisher
Cambridge University Press
external identifiers
  • scopus:85076789733
  • pmid:31843035
ISSN
0033-2917
DOI
10.1017/S0033291719003672
language
English
LU publication?
yes
id
571cc3a3-2a21-46fe-bf8e-8d44dc1bdb19
date added to LUP
2020-01-10 13:48:05
date last changed
2021-02-23 01:20:12
@article{571cc3a3-2a21-46fe-bf8e-8d44dc1bdb19,
  abstract     = {<p>BackgroundAccumulating evidence suggests that many psychiatric disorders etiologically represent the extreme end of dimensionally distributed features rather than distinct entities. The extent to which this applies to eating disorders (EDs) is unknown.MethodsWe investigated if there is similar etiology in (a) the continuous distribution of the Eating Disorder Inventory-2 (EDI-2), (b) the extremes of EDI-2 score, and (c) registered ED diagnoses, in 1481 female twin pairs at age 18 years (born 1992-1999). EDI-2 scores were self-reported at age 18. ED diagnoses were identified through the Swedish National Patient Register, parent-reported treatment and/or self-reported purging behavior of a frequency and duration consistent with DSM-IV criteria. We differentiated between anorexia nervosa (AN) and other EDs.ResultsThe heritability of the EDI-2 score was 0.65 (95% CI 0.61-0.68). The group heritabilities in DeFries-Fulker extremes analyses were consistent over different percentile-based extreme groups [0.59 (95% CI 0.37-0.81) to 0.65 (95% CI 0.55-0.75)]. Similarly, the heritabilities in liability threshold models were consistent over different levels of severity. In joint categorical-continuous models, the twin-based genetic correlation was 0.52 (95% CI 0.39-0.65) between EDI-2 score and diagnoses of other EDs, and 0.26 (95% CI 0.08-0.42) between EDI-2 score and diagnoses of AN. The non-shared environmental correlations were 0.52 (95% CI 0.32-0.70) and 0.60 (95% CI 0.38-0.79), respectively.ConclusionsOur findings suggest that some EDs can partly be conceptualized as the extreme manifestation of continuously distributed ED features. AN, however, might be more distinctly genetically demarcated from ED features in the general population than other EDs.</p>},
  author       = {Dinkler, Lisa and Taylor, Mark J. and Råstam, Maria and Hadjikhani, Nouchine and Bulik, Cynthia M. and Lichtenstein, Paul and Gillberg, Christopher and Lundström, Sebastian},
  issn         = {0033-2917},
  language     = {eng},
  publisher    = {Cambridge University Press},
  series       = {Psychological Medicine},
  title        = {Association of etiological factors across the extreme end and continuous variation in disordered eating in female Swedish twins},
  url          = {http://dx.doi.org/10.1017/S0033291719003672},
  doi          = {10.1017/S0033291719003672},
  year         = {2019},
}