Although research has shown that alcohol dependence and eating disorders are influenced by genetic factors, a new study reveals that the two may be controlled by the same genes, making people with one condition more susceptible to the other.
Melissa Munn-Chernoff, a postdoctoral researcher at the Washington University School of Medicine in St. Louis, writes in a study published Wednesday in the Journal of Studies on Alcohol and Drugs, that the same genetic risk factors that make people more vulnerable to alcoholism also make them more susceptible to certain eating disorder symptoms, such as binge eating and purging, starvation and laxative use.
"We need to be aware that these problems can occur together, in both men and women," Munn-Chernoff said in a statement. "If we can better understand the risk factors, we can better understand how to treat these disorders."
Past studies have shown that there is an association between alcohol abuse and eating disorders, and that women who binge and purge have above average rates of alcohol abuse. The National Eating Disorders Association estimates, for example, that nearly half of all individuals with an eating disorder are also abusing drugs or alcohol – which is a rate five times higher than the rest of the population.
But few studies have actually tested the theory, none looked for a genetic link between the disorders and most studies had only been performed on all-female samples.
Munn-Chernoff and her team analyzed data from nearly 6,000 Australian twins – including men and women, as well as identical and fraternal twins – who reported on their alcohol use and binge eating habits. Women, but not men, were also asked about purging habits.
The researchers found that although it is not clear what genes are involved, a link exists between the disorders in both men and women, and that 38 percent to 53 percent of the risk for developing those disorders could be attributed to those genes.
Munn-Chernoff noted in the study that the research could be expanded to examine potential differences between races and ethnicities and use blood or saliva samples to help identify the specific genes involved.
Still, she said, physicians and therapists who treat patients with either type of disorder should be aware of the link between the two.
"When you go to an eating disorder treatment center, 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," Munn-Chernoff said. "If centers could be aware of that and perhaps treat both problems at the same time, that would be a big help."