Parts of this work have been presented at two scientific meetings (i) Eating Disorders Research Society meeting in Edinburgh, UK, September 2011 and (ii) Norwegian Eating Disorders Research Consortium at Gardermoen, Norway, December 2011.
Version of Record online: 15 OCT 2012
Copyright © 2012 Wiley Periodicals, Inc.
International Journal of Eating Disorders
Volume 46, Issue 4, pages 340–345, May 2013
How to Cite
Winje, E., Torgalsbøen, A.-K., Brunborg, C. and Lask, B. (2013), Season of birth bias and anorexia nervosa: Results from an international collaboration. Int. J. Eat. Disord., 46: 340–345. doi: 10.1002/eat.22060
Supported by Health Southeast and Oslo University Hospital, Regional Department for Eating Disorders.
- Issue online: 6 APR 2013
- Version of Record online: 15 OCT 2012
- Manuscript Accepted: 8 AUG 2012
- season of birth bias;
- eating disorders;
- anorexia nervosa;
- risk factor
Based on inconsistent findings in the literature, this study tested the hypothesis that “there is a season of birth bias for females with anorexia nervosa (AN).”
Females with AN, born in 1975 to 1996, were compared to females born in the same years and geographical regions by chi-square test for contingency tables with known population parameter testing for monthly deviations. Five groups were based on a priori power calculation and geographical location: Iceland, Norway and Sweden (N = 847), United Kingdom (N = 706), Oregon, USA (N = 394), Argentina and Brazil (N = 486), and Australia (N = 381).
The hypothesis was not supported in any of the groups. The associations (Cramér's V) between month of birth and the differences in distributions of births ranged from 0.05 to 0.08, none of which were statistically significant.
The main implication of these findings is that season of birth may not play a significant part in the aetiology of AN. © 2012 by Wiley Periodicals, Inc. (Int J Eat Disord 2013;)