Reuters Health Information

By E.J. Mundell

NEW YORK -- Women are much more likely than their peers to develop anorexia
or bulimia if their sister or mother already suffers from the eating
disorder, researchers report.

The finding suggests that a combination of "family-genetic influences play
an important role in determining susceptibility to eating disorders,"
explained study lead author Dr. Michael Strober of the University of
Pittsburgh, Pennsylvania. His team published their findings in the March
issue of the American Journal of Psychiatry.

The researchers compared rates of eating disorders among the family members
of 323 women (aged 18 to 28 years) with anorexia or bulimia with the rates
in family members of 181 healthy women the same age.

The results? According to Strober, "The rate of bulimia nervosa and anorexia
nervosa amongst female relatives of persons with eating disorders was
between 4 and 11 times higher, (respectively)," compared with the incidence
of these illnesses in women without relatives with the eating disorder. The
rates for eating disorders among male relatives did not appear to be
affected by family members' eating disorders.

Strober told Reuters Health that "milder forms of anorexia nervosa and
bulimia nervosa" -- in which individuals seem morbidly preoccupied with
weight and food, but have not yet lost dangerous amounts of weight -- "also
seemed to run together in families."

In a second study, Dr. Tracey Wade and colleagues at Virginia Commonwealth
University in Richmond, examined rates of anorexia and depression among over
2,100 female twins (both identical and fraternal). Overall, 77 (3.6%) of the
women had been diagnosed as suffering from anorexia, with 6 women having a
twin who shared this diagnosis.

Numerous studies have suggested that genes may predispose individuals to
depression. Wade's team speculates that these latest findings "strongly
suggest that genetic factors also influence the risk for anorexia nervosa."
They estimate that genetic factors may contribute to 58% of the risk for the
eating disorder.

According to Strober's group, it remains unclear which factors play a more
important role -- family environment or genes -- when it comes to the
'clustering' of eating disorders within specific families. Strober notes,
however, that "current research is searching for more specific areas of the
genome that might be associated with risk to these conditions."

SOURCE: American Journal of Psychiatry 2000;157:393-401, 469-471.