Examining selection bias in a population-based cohort study of 522 children with familial high risk of schizophrenia or bipolar disorder, and controls: The Danish High Risk and Resilience Study VIA 7

Mette Falkenberg Krantz*, Carsten Hjorthøj, Ditte Ellersgaard, Nicoline Hemager, Camilla Christiani, Katrine Søborg Spang, Birgitte Klee Burton, Maja Gregersen, Anne Søndergaard, Aja Greve, Jessica Ohland, Preben Bo Mortensen, Kerstin Jessica Plessen, Vibeke Bliksted, Jens Richardt Møllegaard Jepsen, Anne A E Thorup, Ole Mors, Merete Nordentoft

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

PURPOSE: Knowledge about representativity of familial high-risk studies of schizophrenia and bipolar disorder is essential to generalize study conclusions. The Danish High Risk and Resilience Study (VIA 7), a population-based case-control familial high-risk study, creates a unique opportunity for combining assessment and register data to examine cohort representativity.

METHODS: Through national registers, we identified the population of 11,959 children of parents with schizophrenia (FHR-SZ) or bipolar disorder (FHR-BP) and controls from which the 522 children participating in The VIA 7 Study (202 FHR-SZ, 120 FHR-BP and 200 controls) were selected. Socio-economic and health data were obtained to compare high-risk groups and controls, and participants versus non-participants. Selection bias impact on results was analyzed through inverse probability weights.

RESULTS: In the total sample of 11,959 children, FHR-SZ and FHR-BP children had more socio-economic and health disadvantages than controls (p < 0.001 for most). VIA 7 non-participants had a poorer function, e.g. more paternal somatic and mental illness (p = 0.02 and p = 0.04 for FHR-SZ), notifications of concern (FHR-BP and PBC p < 0.001), placements out of home (p = 0.03 for FHR-SZ), and lower level of education (p ≤ 0.01 for maternal FHR-SZ and FHR-BP, p = 0.001 for paternal FHR-BP). Inverse probability weighted analyses of results generated from the VIA Study showed minor changes in study findings after adjustment for the found selection bias.

CONCLUSIONS: Familial high-risk families have multiple socio-economic and health disadvantages. In The VIA 7 Study, although comparable regarding mental illness severity after their child's birth, socioeconomic and health disadvantages are more profound amongst non-participants than amongst participants.

Original languageEnglish
JournalSocial Psychiatry and Psychiatric Epidemiology
Volume58
Issue1
Pages (from-to)113-140
Number of pages28
ISSN0933-7954
DOIs
Publication statusPublished - Jan 2023

Keywords

  • Familial high-risk
  • Generalizability
  • Representativity
  • Severe parental mental illness
  • Socio-economy

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