Season of Birth Bias and Bulimia Nervosa—Results from a Multi‐centre Collaboration

Abstract

There appears not to be any season of birth bias in women with bulimia nervosa in Norway.

Lack of pattern of birth in patients with bulimia nervosa

“…We found no evidence of a season of birth bias in the risk of developing BN in our sample. This result is consistent with the findings of other authors . Only Brewerton et al were able to find significant differences across seasons between patients with and without BN.…”

“…Button and Aldrigde examined a group of 303 women with BN and concluded that, compared with the general population in the United Kingdom, there was no evidence of a season of birth variation in their sample. A recent study of a larger ( n = 549) Norwegian sample reached the same conclusion …”

“…This result is consistent with the findings of other authors. [4][5][6][7][8] Only Brewerton et al 3 were able to find significant differences across seasons between patients with and without BN. These differences could be an artifact because of the small sample size in the BN group (n 5 85).…”

“…A recent study of a larger (n 5 549) Norwegian sample reached the same conclusion. 7 Winje et al 8 reviewed the topic of season of birth bias in eating disorders and concluded that birth season is a risk factor for AN but not for BN. In this review, they purpose some explanations for the found bias and suggest various hypotheses for future research related to geophysical variables like ambient temperature and sunlight exposure.…”

Prenatal and perinatal factors in eating disorders: A descriptive review

“…A season of birth bias provides indirect evidence of the role of infections in eating disorder risk, since the occurrence of many infections tends to follow a seasonal pattern . However, not all studies have found an increased rate of spring births in women with eating disorders …”