Skip to main content
×
×
Home

Family history, place and season of birth as risk factors for schizophrenia in Denmark: A replication and reanalysis

  • Carsten Bøcker Pedersen (a1) and Preben Bo Mortensen (a1)
Abstract
Background

Although a family history of schizophrenia is the strongest individual risk factor for schizophrenia, environmental factors related to urbanicity may contribute to a substantial proportion of the population occurrence of the disease.

Aims

This study replicates previous findings in four mutually exclusive Danish study populations, including out-patient information, ICD–10 diagnoses of schizophrenia, and a broader adjustment for mental illness in family members.

Method

We established a population-based cohort of 2.66 million Danish people using data from the Civil Registration System linked with the Psychiatric Case Register.

Results

Overall, 10 264 persons developed schizophrenia during the 50.7 million person-years of follow-up. The risk of schizophrenia was increased by urbanicity of place of birth and by family history of schizophrenia or other mental disorders.

Conclusions

Urban–rural differences of schizophrenia risk were replicated and could not be associated with the potential sources of bias we assessed. Environmental factors underlying the effect of place of birth are major determinants of schizophrenia occurrence at the population level, although the effect of family history is the strongest at the individual level.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Family history, place and season of birth as risk factors for schizophrenia in Denmark: A replication and reanalysis
      Available formats
      ×
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Family history, place and season of birth as risk factors for schizophrenia in Denmark: A replication and reanalysis
      Available formats
      ×
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Family history, place and season of birth as risk factors for schizophrenia in Denmark: A replication and reanalysis
      Available formats
      ×
Copyright
Corresponding author
Carsten Bøcker Pedersen, National Centre for Register-Based Research, Taasingegade 1, 8000 Aarhus C, Denmark. Tel: +45 89426819; e-mail: cbp@ncrr.au.dk
Footnotes
Hide All

Declaration of interest

The study was supported by the Theodore and Vada Stanley Foundation.

Footnotes
References
Hide All
Agresti, A. (1990) Categorical Data Analysis. Chichester: John Wiley & Sons.
Andersen, P. K., Borgan, Ø., Gill, R. D., et al (1997) Statistical Models Based on Counting Processes. New York: Springer-Verlag.
Breslow, N. E. (1996) Generalized linear models: checking assumptions and strengthening conclusions. Statistica Applicata, 8, 2341.
Breslow, N. E. & Day, N. E. (1980) Statistical Methods in Cancer Research. Vol. I. The Analysis of Case–Control Studies. Lyon: International Agency for Research on Cancer.
Breslow, N. E. & Day, N. E. (1987) Statistical Methods in Cancer Research. Vol. II. The Design and Analysis of Cohort Studies. Lyon: International Agency for Research on Cancer.
Bruzzi, P., Green, S. B., Byar, D. P., et al (1985) Estimating the population attributable risk for multiple risk factors using case–control data. American Journal of Epidemiology, 122, 904914.
Clayton, D. & Hills, M. (1993) Statistical Models in Epidemiology. Oxford: Oxford University Press.
Eaton, W. W., Mortensen, P. B. & Frydenberg, M. (2000) Obstetric factors, urbanization and psychosis. Schizophrenia Research, 43, 117123.
Freeman, H. (1994) Schizophrenia and city residence. British Journal of Psychiatry, 164 (suppl. 23), 3950.
Gottesman, I. I. (1991) Schizophrenia Genesis. The Origins of Madness. New York: W. H. Freeman.
Kendell, R. E., McInneny, K., Juszczak, E., et al (2000) Obstetric complications and schizophrenia. Two case–control studies based on structured obstetric records. British Journal of Psychiatry, 176, 516522.
Lewis, G., David, A., Andreasson, S., et al (1992) Schizophrenia and city life. Lancet, 340, 137140.
Lewis, M. (1989) Age incidence and schizophrenia: Part I. The season of birth controversy. Schizophrenia Bulletin, 15, 5973.
Malig, C. (1996) The civil registration system in Denmark. Technical Papers IIVRS, 66, 16.
Marcelis, M., Takei, N., van Os, J. (1999) Urbanization and risk for schizophrenia: does the effect operate before or around the time of illness onset? Psychological Medicine, 29, 11971203.
McGuffin, P. & Gottesman, I. I. (1999) Risk factors for schizophrenia. New England Journal of Medicine, 341, 370371.
Mortensen, P. B. (2000) What are the causes of urban – rural differences in schizophrenia risk? International Journal of Mental Health, 29, 101110.
Mortensen, P. B., Agerbo, E., Eriksson, T., et al (2000) Parental education and socioeconomic variables as predictors of schizophrenia in their offspring. Schizophrenia Research, 41, 73.
Mortensen, P. B., Pedersen, C. B., Westergaard, T., et al (1999) Effects of family history and place and season of birth on the risk of schizophrenia. New England Journal of Medicine, 340, 603608.
Munk-Jørgensen, P. & Mortensen, P. B. (1997) The Danish Psychiatric Central Register. Danish Medical Bulletin, 44, 8284.
SAS Institute (1997) The GENMOD Procedure. In SAS/STAT Software: Changes and Enhancements through Release 6.12, pp. 247348. Cary, NC: SAS Institute Inc.
Selten, J. P. & Slaets, J. P. (1994) Evidence against maternal influenza as a risk factor for schizophrenia. British Journal of Psychiatry, 164, 674676.
Statistics Denmark (1997a) Befolkningen i kommunerne 1. januar 1997 (Population in Municipalities 1 January 1997). Copenhagen: Statistics Denmark.
Statistics Denmark (1997b) Statistisk Århog 1997 (Statistical Yearbook 1997). Copenhagen: Statistics Denmark.
Suvisaari, J. M., Haukka, J. K., lanskanen, A. J., et al (2000) Decreasing seasonal variation of births in schizophrenia. Psychological Medicine, 30, 315324.
Westergaard, T., Mortensen, P. B., Pedersen, C. B., et al (1999) Exposure to prenatal and childhood infections and the risk of schizophrenia. Suggestions from a study of sibship characteristics and influenza prevalence. Archives of General Psychiatry, 56, 993998.
World Health Organization (1967) Manual of the International Classification of Disease (ICD–8). Geneva: WHO.
World Health Organization (1992) The ICD-10 Classification of Mental and Behavioural Disorders. Clinical Descriptions and Diagnostic Guidelines. Geneva: WHO.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

The British Journal of Psychiatry
  • ISSN: 0007-1250
  • EISSN: 1472-1465
  • URL: /core/journals/the-british-journal-of-psychiatry
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 3
Total number of PDF views: 31 *
Loading metrics...

Abstract views

Total abstract views: 173 *
Loading metrics...

* Views captured on Cambridge Core between 2nd January 2018 - 26th May 2018. This data will be updated every 24 hours.

Family history, place and season of birth as risk factors for schizophrenia in Denmark: A replication and reanalysis

  • Carsten Bøcker Pedersen (a1) and Preben Bo Mortensen (a1)
Submit a response

eLetters

No eLetters have been published for this article.

×

Reply to: Submit a response


Your details


Conflicting interests

Do you have any conflicting interests? *