title: Birth by Caesarean Section and the Risk of Adult Psychosis: A Population-Based Cohort Study.
abstract: Despite the biological plausibility of an association between obstetric mode of delivery and psychosis in later life, studies to date have been inconclusive. We assessed the association between mode of delivery and later onset of psychosis in the offspring. A population-based cohort including data from the Swedish National Registers was used. All singleton live births between 1982 and 1995 were identified (n= 1,345,210) and followed-up to diagnosis at age 16 or later. Mode of delivery was categorized as: unassisted vaginal delivery (VD), assisted VD, elective Caesarean section (CS) (before onset of labor), and emergency CS (after onset of labor). Outcomes included any psychosis; nonaffective psychoses (including schizophrenia only) and affective psychoses (including bipolar disorder only and depression with psychosis only). Cox regression analysis was used reporting partially and fully adjusted hazard ratios (HR) with 95% confidence intervals (CI). Sibling-matched Cox regression was performed to adjust for familial confounding factors. In the fully adjusted analyses, elective CS was significantly associated with any psychosis (HR 1.13, 95% CI 1.03, 1.24). Similar findings were found for nonaffective psychoses (HR 1.13, 95% CI 0.99, 1.29) and affective psychoses (HR 1.17, 95% CI 1.05, 1.31) (χ(2)for heterogeneityP= .69). In the sibling-matched Cox regression, this association disappeared (HR 1.03, 95% CI 0.78, 1.37). No association was found between assisted VD or emergency CS and psychosis. This study found that elective CS is associated with an increase in offspring psychosis. However, the association did not persist in the sibling-matched analysis, implying the association is likely due to familial confounding by unmeasured factors such as genetics or environment.
authors.affiliation: Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland;
authors.forename: Sinéad M
authors.initials: SM
authors.lastname: O'Neill
authors.affiliation: Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland;
authors.forename: Eileen A
authors.initials: EA
authors.lastname: Curran
authors.affiliation: Department of Public Health Sciences, Karolinska Institute, Karolinska, Sweden;
authors.forename: Christina
authors.initials: C
authors.lastname: Dalman
authors.affiliation: Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland; Department of Obstetrics and Gynaecology, Cork University Maternity Hospital, Cork, Ireland;
authors.forename: Louise C
authors.initials: LC
authors.lastname: Kenny
authors.affiliation: Department of Epidemiology and Public Health;
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Kearney
authors.affiliation: Laboratory of NeuroGastroenterology, APC Microbiome Institute; Department of Psychiatry;
authors.forename: Gerard
authors.initials: G
authors.lastname: Clarke
authors.affiliation: APC Microbiome Institute; Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
authors.forename: John F
authors.initials: JF
authors.lastname: Cryan
authors.affiliation: Department of Psychiatry; APC Microbiome Institute;
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Dinan
authors.affiliation: Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland; Department of Epidemiology and Public Health; a.khashan@ucc.ie.
authors.forename: Ali S
authors.initials: AS
authors.lastname: Khashan
mesh_terms: D000293:Adolescent; D000328:Adult; D002585:Cesarean Section / Q000009:adverse effects* / Q000706:statistics & numerical data; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000009:adverse effects* / Q000706:statistics & numerical data; D017558:Elective Surgical Procedures / Q000009:adverse effects* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D011618:Psychotic Disorders / Q000453:epidemiology / Q000209:etiology*; D012042:Registries; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: Caesarean; confounding; mode of delivery; psychosis; sibling control