The New England Journal of Medicine
e-mail icon  FREE NEJM E-TOC    HOME   |   SUBSCRIBE   |   CURRENT ISSUE   |   PAST ISSUES   |   COLLECTIONS   |    Advanced Search
Sign in | Get NEJM's E-Mail Table of Contents — Free | Subscribe
 
Original Article
PreviousPrevious
Volume 340:603-608 February 25, 1999 Number 8
NextNext

Effects of Family History and Place and Season of Birth on the Risk of Schizophrenia
Preben Bo Mortensen, D.M.Sc., Carsten Bøcker Pedersen, M.Sc., Tine Westergaard, M.D., Jan Wohlfahrt, M.Sc., Henrik Ewald, D.M.Sc., Ole Mors, Ph.D., Per Kragh Andersen, D.M.Sc., and Mads Melbye, D.M.Sc.

 Sign up for free e-toc
 

This Article
-Full Text
- PDF

Commentary
-Editorial
 by Andreasen, N. C.
-Letters

Tools and Services
-Add to Personal Archive
-Add to Citation Manager
-Notify a Friend
-E-mail When Cited

More Information
-PubMed Citation
ABSTRACT

Background Although a family history of schizophrenia is the best-established risk factor for schizophrenia, environmental factors such as the place and season of birth may also be important.

Methods Using data from the Civil Registration System in Denmark, we established a population-based cohort of 1.75 million persons whose mothers were Danish women born between 1935 and 1978. We linked this cohort to the Danish Psychiatric Central Register and identified 2669 cases of schizophrenia among cohort members and additional cases among their parents.

Results The respective relative risks of schizophrenia for persons with a mother, father, or sibling who had schizophrenia were 9.31 (95 percent confidence interval, 7.24 to 11.96), 7.20 (95 percent confidence interval, 5.10 to 10.16), and 6.99 (95 percent confidence interval, 5.38 to 9.09), as compared with persons with no affected parents or siblings. The risk of schizophrenia was associated with the degree of urbanization of the place of birth (relative risk for the capital vs. rural areas, 2.40; 95 percent confidence interval, 2.13 to 2.70). The risk was also significantly associated with the season of birth; it was highest for births in February and March and lowest for births in August and September. The population attributable risk was 5.5 percent for a history of schizophrenia in a parent or sibling, 34.6 percent for urban place of birth, and 10.5 percent for the season of birth.

Conclusions Although a history of schizophrenia in a parent or sibling is associated with the highest relative risk of having the disease, the place and season of birth account for many more cases on a population basis.


Source Information

From the Department of Psychiatric Demography, Institute for Basic Psychiatric Research, Psychiatric Hospital, Aarhus University Hospital, Risskov (P.B.M., H.E., O.M.), and the Department of Epidemiology Research, Danish Epidemiology Science Center, Statens Serum Institut, Copenhagen (C.B.P., T.W., J.W., P.K.A., M.M.) — both in Denmark.

Address reprint requests to Dr. Mortensen at the Department of Psychiatric Demography, Institute for Basic Psychiatric Research, Psychiatric Hospital, Aarhus University Hospital, Skovagervej 2, 8240 Risskov, Denmark, or at ph.ph1.pbm{at}aaa.dk.

Full Text of this Article


Related Letters:

Risk Factors for Schizophrenia
McGuffin P., Gottesman I. I., Swerdlow R. H., Binder D., Parker W. D., Weilerstein R., Mortensen P. B., Pedersen C. B., Ewald H.
Extract | Full Text  
N Engl J Med 1999; 341:370-372, Jul 29, 1999. Correspondence

This article has been cited by other articles:



HOME  |  SUBSCRIBE  |  SEARCH  |  CURRENT ISSUE  |  PAST ISSUES  |  COLLECTIONS  |  PRIVACY  |  TERMS OF USE  |  HELP  |  beta.nejm.org

Comments and questions? Please contact us.

The New England Journal of Medicine is owned, published, and copyrighted © 2009 Massachusetts Medical Society. All rights reserved.