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. Aims: 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.

• Bipolar disorder
• Methodology
• Prenatal
• Register-based study
• Risk factors

Acknowledgement—

We thank the study investigators and staff at medical centers involved in this research. Specifically we would like to thank the members involved in the data collection process including: Juha-Pekka Virtanen, Pyry Kantanen, Kristiina Saanakorpi, Ulla Kulmala, Tanja Sarlin, Jarna Lindroos and Lauri Sillanmäki from Research Institute of Child Psychiatry, Turku University and Pilar Cordova from Columbia University.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

The study was supported by grants from NARSAD Independent Investigator Award, USA (A.S) and Sigrid Juselius Foundation, Finland (A.S). The study was conducted at University of Turku, Finland.