Washington University researchers have found that some of
the same genes may be involved in alcohol dependence and eating disorders.
Part of the risk for alcohol dependence is genetic, and the
same is true for eating disorders. Now, researchers at Washington University
School of Medicine in St Louis have found it’s likely that some of the same genes
are involved in both.
In the September issue of the Journal of Studies on Alcohol
and Drugs, the researchers report that people with alcohol dependence may be
more genetically susceptible to certain types of eating disorders and vice
“In clinical practice, it’s been observed that individuals
with eating disorders also have high rates of alcohol abuse and dependence,”
said Melissa A. Munn-Chernoff, PhD, the study’s first author. “Other studies
have focused on the genetic connections between alcohol dependence and eating
disorders, but all of those studies looked only at women. Ours was the first to
include men as well.”
According to Munn-Chernoff, a postdoctoral research scholar
in psychiatry, that’s important because although eating disorders tend to be
thought of as a female problem, they affect men, too.
Studying data gathered from nearly 6 000 adult twins in
Australia, Munn-Chernoff and her colleagues found that common genetic factors
underlie alcoholism and certain eating-disorder symptoms, such as binge eating
and purging habits that include self-induced vomiting and the abuse of
By studying twins, the researchers used statistical methods
to determine the odds that certain traits result from the same genes. Those
statistical insights are based on the fact that identical twins share 100% of
their genetic makeup while fraternal twins share about half.
“By comparing the findings in identical and fraternal twins,
we can develop estimates of how much of the difference in particular traits is
due to genes or environment,” Munn-Chernoff explained. “We found that some of
the genes that influence alcohol dependence also influence binge eating in men
Even with the growing awareness and more frequent diagnoses
of problems such as anorexia nervosa and bulimia nervosa, rates of the
full-blown forms of these disorders are relatively low, and they’re rare in
populations of twins. So the researchers surveyed study subjects about whether
they suffered from eating-disorder symptoms.
“The symptoms can cut across multiple eating disorder
diagnoses,” said Munn-Chernoff. “And several past studies have suggested that
the particular behaviour of binge eating, as well as purging and other practices
that we call compensatory behaviours, may be closely associated with alcohol
dependence, which is why we focused on those symptoms.”
All of the men and women in the study were surveyed about
their alcohol use and binge eating, but because the researchers were analysing
data that had been gathered previously for a different study, not everyone was
asked about compensatory behaviours, such as purging or using laxatives and
diuretics. Only the female twins were asked about those symptoms.
In all, nearly 25% of the men and 6% of women had been
alcohol dependent at some point. Almost 11% of these same men and 13% of the
women had experienced problems with binge eating. In addition, about 14% of the
women had engaged in purging or abuse of laxatives or diuretics.
On a statistical scale that runs from zero (no shared genes)
to 1 (all genes shared), the researchers found that the genetic correlation
between binge eating and alcohol dependence was statistically significant at 26.
Among women in the study, the genetic correlation between
compensatory behaviours and alcohol dependence was significant at 32.
“Those numbers suggest that there are shared genetic risk
factors for these behaviours, such as purging and fasting,” said Munn-Chernoff.
“It appears that some genes that influence alcohol dependence also influence
binge eating in men and women, and compensatory behaviours in women.”
In the future, Munn-Chernoff would like to expand the scope
of the study. Because most of the twins in this data set were Caucasian, she’d
like to study twins of different races to see whether these genetic findings
occur in other ethnic groups. She also would like to get beyond statistical
relationships and gather blood or saliva samples in an attempt to identify the
actual genes that contribute both to alcohol dependence and eating-disorder
She believes physicians and therapists who treat people for
alcohol dependence and eating disorders should be more aware that the problems
can occur together.
“When you go to an eating disorder treatment centre, they
don’t often ask questions about alcoholism. And when you go for alcoholism
treatment, they don’t generally ask questions about eating disorder symptoms,”
she said. “If centres could be aware of that and perhaps treat both problems at
the same time, it would be a big help.”