In March 2006, the Archives of General Psychiatry published an article by Bulik et al1 on the heritability of anorexia nervosa based on the Swedish Twin Registry. Table 4 of the article (p 310) provided descriptive data for univariate analysis of anorexia nervosa. In this table, column headings were divided into “T1-No/T2-No”; “T1-Yes/T2-No”; and “T1-Yes/T2-Yes.” The table note stated that T1 equaled twin 1, and T2 equaled twin 2. For the row designated “DZ-MF [dizygotic–male/female]” under the “Narrow DSM-IV AN [anorexia nervosa]” heading, 2212 twin pairs were “T1-No/T2-No,” meaning that neither twin was affected; 0 were “T1-Yes/T2-Yes,” meaning no dizygotic twinship discordant for sex had both affected; and 16 were “T1-Yes/T2-No.” As there is a DZ-FM row above this one, the most logical interpretation is that T1 refers to the first twin by sex in a dizygotic twinship. This interpretation of Table 4 was used by Procopio and Marriott2 in their reanalysis of the data. Their reanalysis indicated that for a male with a female co-twin, the risk for anorexia nervosa was nearly 10-fold the risk in twinships consisting of males alone and approached the risk for females.
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Purchase Online Access to this article for 24 hours
Thank you for submitting a comment on this article. It will be reviewed by JAMA Psychiatry editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest*
Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 2
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
and access these and other features:
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.