Are anorexia nervosa, bulimia nervosa, and binge-eating rare disorders? Not at all. Research outlines that 4 out of 10 individuals living in Western Europe will get through this at some point in their lives. However, lately, studies on genetic sources showed that eating disorders have some things in commoin with different psychiatric disorders.
The collected data that points out the similar root of both eating disorder and psychiatric disorders was taken from tens of thousands of British people by a team from the University of Geneva (UNIGE), the University Hospitals of Geneva (HUG), King’s College London, the University College London, the University of North Carolina (UNC) and The Icahn School of Medicine at Mount Sinai.
Eating disorders have complex genetic associations with anthropometric traits, like weight, waist circumference, or body mass index, but they share this genetic predisposition that plays a considerable role. And it’s more to come. The whole study was published in the International Journal of Eating Disorders.
According to Nadia Micali, Professor, Department of Psychiatry, Faculty of Medicine, University of Geneva, Head, Division of Child and Adolescent Psychiatry, University Hospitals of Geneva:
“Previous studies, which highlighted a genetic association between a high risk of anorexia nervosa and a low risk of obesity, have begun to lift the veil on certain aspects of how eating disorders develop that had been mostly neglected until then.”
“However, the same work has not been done for the two other major eating disorders: bulimia nervosa and binge-eating disorder. The goal of our study was to understand similarities and differences amongst all eating disorders in the role of genes governing body weight.”
What the Genome of Over 20,000 People Revealed
In order to analyze what these disorders share in common and what not, the researchers took in account the genomes of more than 20,000 people. The data was taken from extensive population-based studies:the UK Biobank and the Avon Longitudinal Study of Parents and Children.
Dr Christopher Hübel, from King’s College London answered :
“We were able to access volunteer’s DNA, their basic health data (weight, age, etc.) and responses to health questionnaires, including possible psychiatric disorders and their eating disorder history. We are grateful for this access as we were able to conduct multifactorial analyses and calculate more than 250 polygenic scores for each person.
“Each polygenic score sums the risk genes involved in a specific trait, such as depression, for example. We calculated polygenic scores for psychiatric disorders, such as schizophrenia and obsessive-compulsive disorder, and metabolic and physical traits, including insulin sensitivity, obesity and high BMI.Thus, the higher the score, the greater the genetic risk, whether it is blue eyes or the development of a given disease.”
The team of scientists analyzed the links between the polygenic scores of these volunteers, such as genetic predispositions to psychiatric and metabolical problems and other traits and the eating disorder rate.
While scientists were looking for corelations between compulsive eating, anorexia nervosa and bulimia nervosa, the differences are not out of sight.
Nadia Micali pinpoints some similarities:
“The similarities lie in the association with psychiatric risks: anorexia nervosa, bulimia nervosa and binge-eating disorder share genetic risk with certain psychiatric disorders, in particular for schizophrenia and depression, thus confirming the strong psychiatric component of these diseases.
“However, the big difference concerns the associated genetics of body weight regulation, which are opposite between anorexia on the one hand, and bulimia nervosa and binge-eating disorder on the other, the latter being linked to a high genetic risk of obesity, and high BMI.”
However, two individuals suffering from the same psychiatric genetic risk might turn one to obesity and the other to anorexia, depending on the genetic predisposition to gain weight or lose weight.
“The metabolic and physical component would therefore direct the individual either towards anorexia nervosa or towards bulimia nervosa or binge-eating disorder”
Nadia Micali also declares:
“Moreover, this study confirms a clear genetic relationship between binge-eating disorder and attention deficit hyperactivity disorder (ADHD), that was already clinically observed, which might be linked to greater impulsivity, which is shared by these disorders.”
The study may build a future understanding of genetic patterns in body weight regulation and the evolution of eating disorders.
Study of Over 20,000 Individuals Sheds Light on Genetic Contributions to Eating Disorders