Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-29T14:53:34.987Z Has data issue: false hasContentIssue false
  • English
  • Français

Annual variation in birth rate of people who subsequently develop schizophrenia

Published online by Cambridge University Press:  03 January 2018

W. Adams  and
R. E. Kendell
W. Adams
Affiliation:
University of Edinburgh Medical School, Edinburgh
R. E. Kendell*
Affiliation:
University of Edinburgh Medical School, Edinburgh
*
Dr R. E. Kendell, 3 West Castle Road, Edinburgh EH10 5AT
Get access Rights & Permissions [Opens in a new window]

Abstract

Background

Previous attempts to decide whether there is significant year-to-year variation in the birth rate of people who subsequently develop schizophrenia have given conflicting results, probably because of differences in the statistical methods employed.

Aims

To determine whether there is significant year-to-year variation in the birth rate.

Method

Variation in the birth rate for the period 1921–1960 was studied in three separate national data sets – English, Danish and Scottish – using cubic splines to smooth the distribution curve before calculating residuals from a Poisson distribution.

Results

Over-dispersion was found in all three data sets, particularly in the Danish and Scottish data. However, the correlation between the sets of standardised residuals derived from the three data sets was only statistically significant for Denmark v. England.

Conclusions

There was statistically significant year-to-year variation in the birth rate of people who subsequently developed schizophrenia in three countries in north-west Europe in the years 1921–1960. This is potentially a clue to the nature of the environmental determinants of schizophrenia, but better data will be needed before useful explanatory hypotheses can be generated and tested.

Type
Papers
Information
The British Journal of Psychiatry , Volume 175 , Issue 6 , December 1999 , pp. 522 - 527
Copyright
Copyright © 1999 The Royal College of Psychiatrists 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Declaration of interest

No external funding; no conflict of interest.

References

Adam, W., Kendell, R. E., Hare, E. H., et al (1993) Epidemiological evidence that maternal influenza contributes to the aetiology of schizophrenia. An analysis of Scottish. English, and Danish data. British Journal of Psychiatry, 163, 522–534.Google Scholar
Box, G. & Jenkins, G. (1976) Time Series Analysis: Forecasting and Control. San Francisco, CA: Holden–Day.Google Scholar
Efron, B. & Tibshirani, R. J. (1993) An Introduction to the Bootstrap. Monographs on Statistics and Applied Probability, No. 57. New York: Chapman & Hall.CrossRefGoogle Scholar
Genstat 5 Committee (1993) Release 3 Reference Manual. Oxford: Clarendon.Google Scholar
Hastie, T. J. & Tibshirani, R. J. (1990) Generalised Additive Models. Monographs on Statistics and Applied Probability, No. 43. London: Chapman & Hall.Google Scholar
Kendell, R. E. & Adams, W. (1991) Unexplained fluctuations in the risk for schizophrenia by month and year of birth. British Journal of Psychiatry, 158, 758–763.CrossRefGoogle ScholarPubMed
Torrey, E. F. & Rawlings, R. R. (1996) Fluctuations in schizophrenic births by year. British Journal of Psychiatry 169, 772–775.CrossRefGoogle ScholarPubMed
Torrey, E. F., Miller, J., Rawlings, R., et al (1997) Seasonality of births in schizophrenia and bipolar disorder: a review of the literature. Schizophrenia Research, 28, 1 38.Google Scholar
World Health Organization (1967) Manual of the International Statistical Classifications of Diseases, Injuries and Causes of Death, 1965 revision (ICD–8). Geneva: WHO.Google Scholar
World Health Organization (1978) Mental Disorders: Glossary and Guide to their Classification in Accordance with the Ninth Revision of the International Classification of Diseases (ICD–9). Geneva: WHO.Google Scholar
Submit a response

eLetters

No eLetters have been published for this article.