Males with a female twin may be at higher risk for anorexia nervosa

Dec 03, 2007

Males who have a twin sister appear more likely to develop the eating disorder anorexia nervosa than other males, including those with a twin brother, according to a report in the December issue of Archives of General Psychiatry, one of the JAMA/Archives journals. This finding supports the hypothesis that exposure to female sex hormones in the womb may be related to the risk for anorexia nervosa.

“Anorexia nervosa is approximately 10 times more common in females than in males,” the authors write as background information in the article. “The reasons for this difference are not known, and it is likely that their unraveling will represent an important step forward in the understanding of the etiopathogenetic factors involved in the development of eating disorders.”

Marco Procopio, M.D., M.R.C.Psych., of the University of Sussex, Brighton, England, and Paul Marriott, Ph.D., of the University of Waterloo, Ontario, Canada, analyzed data from a study of Swedish twins born between 1935 and 1958. Two sets of diagnostic criteria, one broader and one more narrow, were used to determine which twins had anorexia nervosa.

Overall, female twins were more likely than male twins to develop anorexia nervosa. The one exception was among males who had a dizygotic (fraternal) twin sister. “In fact, their risk is at a level that is not statistically significantly different from that of females from such a pair,” the authors write. Among 4,478 dizygotic opposite-sex twins, 20 females and 16 males had anorexia nervosa using narrow criteria and 32 females and 27 males qualified under the broad criteria. Risk for these female twins was not significantly different from than that of other female twins.

“A plausible explanation for this phenomenon is that in pregnancies bearing a female fetus, a substance is produced, probably hormonal, that increases the risk of having anorexia nervosa in adulthood,” the authors write. “Because the male half of an opposite-sex twin pair would also be exposed to this substance, it could account for the observed elevated risk in males with female twins. The most likely candidates are sex steroid hormones.”

Source: JAMA and Archives Journals

Explore further: Why some antidepressants may initially worsen symptoms

add to favorites email to friend print save as pdf

Related Stories

Fingers pointed as climate talks deadlock

5 hours ago

Accusations flew at deadlocked UN climate talks in Lima on Saturday, as the United States warned that failure to compromise could doom the 22-year-old global forum.

Fun cryptography app pleases students and teachers

15 hours ago

Up on Google Play this week is Cryptoy...something that you might want to check out if you or someone you know wishes entry into the world of cryptography via an educational and fun app. You learn more about ciphers and keys; you ...

Recommended for you

Despite risks, benzodiazepine use highest in older people

13 hours ago

Prescription use of benzodiazepines—a widely used class of sedative and anti-anxiety medications—increases steadily with age, despite the known risks for older people, according to a comprehensive analysis of benzodiazepine ...

Why some antidepressants may initially worsen symptoms

17 hours ago

New research helps explain a paradoxical effect of certain antidepressants—that they may actually worsen symptoms before helping patients feel better. The findings, highlighted in a paper publishing online December 17 in ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.