Season of birth and schizophrenia: A systematic review and meta-analysis of data from the southern hemisphere

McGrath, JJ and Welham, JL (1999) Season of birth and schizophrenia: A systematic review and meta-analysis of data from the southern hemisphere. Schizophrenia Research, 35 3: 237-242. doi:10.1016/S0920-9964(98)00139-X


Author McGrath, JJ
Welham, JL
Title Season of birth and schizophrenia: A systematic review and meta-analysis of data from the southern hemisphere
Journal name Schizophrenia Research   Check publisher's open access policy
ISSN 0920-9964
Publication date 1999-01-01
Sub-type Article (original research)
DOI 10.1016/S0920-9964(98)00139-X
Volume 35
Issue 3
Start page 237
End page 242
Total pages 6
Editor H. Nasrallah
L. DeLisi
Place of publication New York
Publisher Elsevier
Collection year 2000
Language eng
Subject C1
321021 Psychiatry
730211 Mental health
Abstract Aims: Data from the Northern Hemisphere support an excess of winter-spring births of individuals who later develop schizophrenia when compared with the general population. The data from the Southern Hemisphere have been less consistent. This paper will present a systematic review and mete-analysis of relevant data from the Southern Hemisphere. Methods: To identify relevant studies we searched electronic databases, reviewed citations from target publications and wrote letters to published authors in the field. The counts for observed and expected births were assessed in four planned comparisons. In the absence of significant heterogeneity, the data were combined using Mantel-Haenzel odds ratio in a fixed effect model. Results: Twelve studies were identified. Published and unpublished data from eight of these were able to be included in the analyses. For the two seasonal comparisons (n=20 017), small but non-significant excesses were found in the first comparison (winter versus other seasons; OR=1.04, 0.99-1.08) and for the second comparison (winter and spring versus other seasons; OR=1.03, 0.99-1.07). For the two quarterly comparisons (n= 14 799), there was a small but non-significant excess found in the third comparison (third quarter versus other quarters; OR=1.03, 0.98-1.09), and a small but non-significant deficit in the fourth comparison (third and fourth quarter versus other quarters OR=0.99, 0.95-1.04). Conclusions: Assuming that season of birth acts as a proxy marker for fluctuating non-genetic risk-modifying factors for schizophrenia, this review suggests that in the Southern Hemisphere these factors may be weaker, less prevalent, less regular, and/or may be modified by other confounding or modifying variables. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Keyword Psychiatry
Schizophrenia
Seasonality
Season Of Birth
Meta-analysis
Disorder
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Medicine Publications
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 74 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 91 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Tue, 10 Jun 2008, 23:19:32 EST