Alcoholism, eating disorders and genes

A study suggests that a common set of genes may increase risk for alcohol dependence and eating disorders. (Rick Loomis / Los Angeles Times)

A new statistical analysis suggests that alcohol dependence and binging and purging behaviors, all believed to be influenced by genetic factors, may actually be influenced by the same genes.

Writing in the Journal of Studies on Alcohol and Drugs, Washington University School of Medicine postdoctoral researcher Melissa Munn-Chernoff and colleagues reported that genetic risk factors that make people susceptible to alcoholism also appear to influence risk for binge eating in both men and women and for “compensatory behaviors” such as starvation, laxative use and self-induced vomiting in women.

Though prior studies had already demonstrated that bulimic women who binge and purge are more likely than other women, including those with other types of eating disorders, to have alcohol dependence issues, this was the first analysis to extend some portion of the analysis to men, Munn-Chernoff said.

The team studied data collected from 5,993 adult identical and fraternal twins in Australia, who reported on their their alcohol use and their binge eating habits, among other details about their health. (Women, but not men, were also asked about compensatory behaviors such as purging.)

By analyzing incidence of alcoholism and binging and purging behaviors in the identical twins (who share the same DNA entirely) and in the fraternal twins (who share half their DNA), the researchers were able to tease out how heredity influenced the disorders, concluding that 38% to 53% of the risk was genetic.  They were also able to calculate that a significant portion of the genetic risk for alcohol dependence, for binging and for purging was shared risk — associated with at least some of the same genes.

The study did not identify what those specific genes might be,  but Munn-Chernoff said she hoped to obtain genetic samples from blood or saliva to try to figure that out.  

In the meantime, she said, she hoped that treatment programs for alcoholism and for eating disorders would become more aware that the conditions often occur together. “If centers could be aware of that and perhaps treat both problems at the same time, that would be a big help,” she said.

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