title: Maternal Grand Multiparity and the Risk of Severe Mental Disorders in Adult Offspring.
abstract: Previous studies have shown that maternal grand multiparity may predict an increased risk of mental disorders in young adult offspring, but whether such effects persist throughout adulthood remains unknown. The current study examined if maternal grand multiparity predicts the risks of severe mental disorders, suicides, suicide attempts and dementias throughout adult life.
  
  
  
  Our study sample comprised 13243 Helsinki Birth Cohort Study 1934-1944 participants (6905 men and 6338 women). According to hospital birth records, 341 offspring were born to grand multiparous mothers. From Finnish national hospital discharge and causes of death registers, we identified 1682 participants diagnosed with mental disorders during 1969-2010.
  
  
  
  Maternal grand multiparity predicted significantly increased risks of mood disorders (Hazard Ratio = 1.64, p = 0.03), non-psychotic mood disorders (Hazard Ratio = 2.02, p = 0.002), and suicide attempts (Hazard Ratio = 3.94, p = 0.01) in adult offspring. Furthermore, women born to grand multiparous mothers had significantly increased risks of any severe mental disorder (Hazard Ratio = 1.79, p = 0.01), non-psychotic substance use disorders (Hazard Ratio = 2.77, p = 0.02) schizophrenia, schizotypal and delusional disorders (Hazard Ratio = 2.40, p = 0.02), mood disorders (Hazard Ratio = 2.40, p = 0.002), non-psychotic mood disorders (Hazard Ratio = 2.91, p<0.001), and suicide attempts (Hazard Ratio = 5.05, p = 0.01) in adulthood. The effects of maternal grand multiparity on offspring psychopathology risk were independent of maternal age and body mass index at childbirth, and of year of birth, sex, childhood socioeconomic position, and birth weight of the offspring. In contrast, no significant effects were found among men.
  
  
  
  Women born to grand multiparous mothers are at an increased risk of severe mental disorders and suicide attempts across adulthood. Our findings may inform the development of preventive interventions for mental disorders.
authors.affiliation: Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Marius
authors.initials: M
authors.lastname: Lahti
authors.affiliation: National Institute for Health and Welfare, Diabetes Prevention Unit, Helsinki, Finland; Institute of Clinical Medicine, University of Helsinki, Helsinki, Finland; Vaasa Central Hospital, Vaasa, Finland; Unit of General Practice, Helsinki University Central Hospital, Helsinki, Finland; Folkhälsan Research Centre, Helsinki, Finland.
authors.forename: Johan G
authors.initials: JG
authors.lastname: Eriksson
authors.affiliation: Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Kati
authors.initials: K
authors.lastname: Heinonen
authors.affiliation: National Institute for Health and Welfare, Diabetes Prevention Unit, Helsinki, Finland; Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland; Department of Obstetrics and Gynaecology, MRC Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
authors.forename: Eero
authors.initials: E
authors.lastname: Kajantie
authors.affiliation: Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Jari
authors.initials: J
authors.lastname: Lahti
authors.affiliation: National Institute for Health and Welfare, Diabetes Prevention Unit, Helsinki, Finland; The Finnish Association for Mental Health, Helsinki, Finland.
authors.forename: Kristian
authors.initials: K
authors.lastname: Wahlbeck
authors.affiliation: Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Soile
authors.initials: S
authors.lastname: Tuovinen
authors.affiliation: Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Anu-Katriina
authors.initials: AK
authors.lastname: Pesonen
authors.affiliation: National Institute for Health and Welfare, Diabetes Prevention Unit, Helsinki, Finland.
authors.forename: Maiju
authors.initials: M
authors.lastname: Mikkonen
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom.
authors.forename: Clive
authors.initials: C
authors.lastname: Osmond
authors.affiliation: Institute of Behavioural Sciences, University of Helsinki, Helsinki, Finland.
authors.forename: Katri
authors.initials: K
authors.lastname: Räikkönen
mesh_terms: D000328:Adult; D032721:Adult Children / Q000523:psychology / Q000706:statistics & numerical data; D003704:Dementia / Q000209:etiology; D005260:Female; D000066502:Grandparents; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000209:etiology*; D019964:Mood Disorders / Q000209:etiology; D010298:Parity; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000209:etiology; D013405:Suicide / Q000706:statistics & numerical data; D013406:Suicide, Attempted / Q000706:statistics & numerical data; D055815:Young Adult