Anorexia, bulimia prove gene related

Six core traits that appear to be linked to genes associated with two common eating disorders, anorexia and bulimia nervosa, have been identified by an international team of researchers led by investigators at the University of Pittsburgh (Pa.) School of Medicine. Approximately 10,000,000 females and 1,000,000 males nationwide are affected by either anorexia or bulimia. The findings bring researchers closer to identifying specific genes and also may have implications for genetic studies of other complex genetic disorders.

These six core traits are: "obsessionality" (a form of perfectionism); age at menarche (menstruation); anxiety; lifetime minimum body mass index (BMI), a measure of body size based on height and weight; concern over mistakes; and food-related obsessions.

The studies found that minimum BMI, concern over mistakes, age at menarche, and food-related obsessions appear to be more closely linked to bulimia, whereas obsessionality and anxiety seem to be more connected to anorexia, suggesting that, although related, the two conditions have some underlying differences.

Historically, anorexia and bulimia have been considered closely related disorders or manifestations of the same disorder that is influenced primarily by social and cultural norms, such as society's emphasis on thinness and being attractive. In recent years, however, research increasingly has pointed to substantial biological and genetic contributions as well.

Anorexia nervosa is characterized by the relentless pursuit of thinness and obsessive fears of being fat. Self-starvation, extreme weight loss, and related medical complications that accompany the disorder can result in death. In contrast, bulimia nervosa is marked by recurrent episodes of binge eating, followed by self-induced vomiting, fasting, excessive exercise, or misuse of laxatives or other substances to prevent weight gain.

Although people with bulimia usually maintain a normal weight, they, too, often have an obsessive fear of adding bulk, express a constant desire to shed pounds, and report feeling intensely dissatisfied with their bodies.

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