title: Finnish Prenatal Study of Bipolar Disorders (FIPS-B): overview, design and description of the sample.
abstract: BACKGROUND
  Bipolar disorders (BPD) are chronic mental illnesses, the development of which involves genetic factors and environmental influences.
  
  
  OBJECTIVE
  The aim of this paper is to provide an overall description of the Finnish Prenatal Study of Bipolar Disorders (FIPS-B), including the study design, national registers and linkage of the registers.
  
  
  METHODS
  FIPS-B is a population-based prenatal epidemiological study of BPD with a nested case-control study design using several national registers. The registers used are: the Finnish Medical Birth Register (FMBR), the Finnish Hospital Discharge Register (FHDR), the Population Central Register and the Finnish Maternity Cohort (FMC), which are linked using the unique personal identity code (PIC). FIPS-B includes all children born from January 1, 1983 to December 31, 1998 and diagnosed with BPD in Finland by December 31, 2008.
  
  
  RESULTS
  The total number of cases included in the FIPS-B is 1887. The age at first diagnosis ranged from 4 to 25 years. Half (50.4%) of the cases utilized only outpatient services, 12.7% only inpatient services and the rest (36.9%) utilized both services. Offspring of mothers with the lowest educational level had an increased odds of BPD (OR = 1.46, 95% CI 1.13-1.88). The cumulative incidence of BPD in the population aged 25 years or younger was 11.6/10,000 in 2008.
  
  
  CONCLUSIONS
  FIPS-B has all the strengths of a register-based prenatal epidemiological study, along with the availability of maternal biomarkers, enabling it to examine several prenatal, perinatal and familial risk factors for BPD.
authors.affiliation: Department of Child Psychiatry, University of Turku , Finland.
authors.forename: Roshan
authors.initials: R
authors.lastname: Chudal
authors.forename: Dan
authors.initials: D
authors.lastname: Sucksdorff
authors.forename: Auli
authors.initials: A
authors.lastname: Suominen
authors.forename: Venla
authors.initials: V
authors.lastname: Lehti
authors.forename: Susanna
authors.initials: S
authors.lastname: Hinkka-Yli-Salomäki
authors.forename: Jukka
authors.initials: J
authors.lastname: Huttunen
authors.forename: Terja
authors.initials: T
authors.lastname: Ristkari
authors.forename: Mika
authors.initials: M
authors.lastname: Gissler
authors.forename: Ian W
authors.initials: IW
authors.lastname: McKeague
authors.forename: Alan S
authors.initials: AS
authors.lastname: Brown
authors.forename: Andre
authors.initials: A
authors.lastname: Sourander
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001714:Bipolar Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003625:Data Collection / Q000379:methods; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D007297:Inpatients / Q000706:statistics & numerical data; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis / Q000453:epidemiology; D010045:Outpatients / Q000706:statistics & numerical data; D010351:Patient Discharge / Q000706:statistics & numerical data; D011247:Pregnancy; D011295:Prenatal Care / Q000706:statistics & numerical data*; D012042:Registries; D012107:Research Design; D012307:Risk Factors; D055815:Young Adult