People with alcohol abuse problems may share the same genetic susceptibility toward certain types of eating disorders, a new study suggests.
The findings are important given that particular behaviors seen in eating disorders, like binge eating, have long been associated with a greater tendency toward alcohol abuse, the researchers from Washington University School of Medicine said.
"Other studies have focused on the genetic connections between alcohol dependence and eating disorders, but all of those studies looked only at women," study author Melissa A. Munn-Chernoff said in a statement. "Ours was the first to include men as well."
Twin studies reveal nature vs. nurture
Analyzing data on nearly 6,000 adult twins in Australia, the team found that compensatory behaviors in eating disorders, like self-induced vomiting or laxative abuse, underlie alcoholism via a genetic link. By studying fraternal and identical twins, the researchers were able to determine which traits resulted from genetic predisposition and which ones could have resulted from environmental influences.
"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 and women."
Nearly 25 percent of the men and 6 percent of the women in the study had been alcohol-dependent at some point. Eleven percent of these same men and 13-14 percent of the women had also reported problems with binge eating or abuse of laxatives or diuretics.
Using a statistical scale that ran from zero to 1 – with zero representing no shared genes between alcoholism and eating disorders and 1 representing all genes shared – the genetic correlation between the two was found to be "statistically significant" at 0.26.
"Those numbers suggest that there are shared genetic risk factors for these behaviors, 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 behaviors in women."
Implications for treatment
Therapists and doctors who address eating disorders and alcohol dependence should be more aware of the genetic link between the two problems, Munn-Chernoff said.
"When you go to an eating disorder treatment center, they don't often ask questions about alcoholism," she said. "And when you go for alcoholism treatment, they don't generally ask questions about eating disorder symptoms. If centers could be aware of that and perhaps treat both problems at the same time, that would be a big help."
The study can be found in the September issue of the Journal of Studies on Alcohol and Drugs.
Source: Washington University in St. Louis