Nearly 30 million Americans will have an eating disorder at some point during their lives, and that number continues to grow. Eating disorders such as anorexia nervosa, bulimia nervosa and binge-eating disorder cause significant distress to the people living with them and have ripple effects through their careers and relationships. These disorders also can cause significant health issues, including heart complications, gastrointestinal problems, osteoporosis and cognitive impairment, and they can hinder growth in young people. In the most severe cases, eating disorders can be fatal.
The role of genetics in eating disorders has been a subject of research for decades. Studies of families and twins have confirmed that eating disorders run in families because of shared genetic factors. However, the human genome contains about 20,000 genes, and scientists aren’t yet sure how many play a role in who develops eating disorders and what type of treatment may help.
Cynthia Bulik, PhD, founding director of the Center of Excellence for Eating Disorders at the UNC School of Medicine, is leading an international study funded by the National Institute of Mental Health called the Eating Disorders Genetics Initiative (EDGI), which aims to identify hundreds of genes that influence a person’s risk of developing an eating disorder. She walks us through what we already know, and how information collected from EDGI will help clinicians and patients going forward.
How do genetics play a role in eating disorders?
Eating disorders are complex mental illnesses. Many factors influence whether someone will develop an eating disorder, including genetics, thinking styles—such as perfectionism—body dissatisfaction, and societal or cultural pressures to be thin. Although environment definitely plays a role, recent research has shown that between 40 and 60 percent of the vulnerability to develop an eating disorder is due to genetic factors. Our latest global study revealed that the genetic factors that influence anorexia nervosa are related to both psychological and metabolic factors. For example, some of the same genes that increase your risk for developing type 2 diabetes decrease your risk for developing anorexia nervosa. This work suggested that anorexia nervosa is a metabo-psychiatric illness [with both metabolic and psychiatric causes] and may explain why some people living with the disorder struggle to gain weight despite their best efforts.
What will the EDGI study help us learn about genetics and eating disorders?
EDGI is the largest-ever genetic research study of eating disorders. It follows the groundbreaking advances that have been made through another collaborative study, the Anorexia Nervosa Genetics Initiative (ANGI), in which our team of researchers identified both psychiatric and metabolic causes for anorexia nervosa.
ANGI was a genomewide association study, or GWAS, in which we compare the entire genomes of large groups of people with a particular illness to large groups of people without the illness to see where differences lie. ANGI compared DNA samples from almost 17,000 participants who experienced anorexia nervosa with samples from more than 55,000 people who didn’t experience it. This comparison allowed us to look for areas on the genome that differed significantly between people with anorexia compared to people without anorexia. We identified eight regions on the genome that contained genetic variants that were significantly associated with anorexia.
EDGI is also a GWAS, but it is bigger and broader—this time we’re studying anorexia nervosa, bulimia nervosa and binge-eating disorder. The study will allow researchers to identify more genetic factors that determine why some people experience eating disorders while others do not, and why some people living with eating disorders respond to certain treatments while others do not.
In addition, comparing the DNA samples of EDGI participants to samples collected for other disorders will help us understand the common conditions co-occurring with eating disorders, including depression, anxiety, obsessive-compulsive disorder, substance abuse disorders and personality disorders. This knowledge will be used to improve existing treatments and to develop new treatments for eating disorders that will save lives.
How can someone participate in EDGI, and what is it like?
Participation in the EDGI research study is confidential and easy. If you are 18 or older—21 in Puerto Rico—first, you complete an online survey. If you’re a good fit for the study, you are invited to complete more online surveys about eating, mood and life experiences and are sent a saliva sampling kit for DNA. After finishing the surveys and returning the saliva kit, you receive a $20 Amazon gift card. If you live in another country, you can explore other EDGI locations.
Our hope is that the results will help us develop new treatments that target the biology of the illnesses and help us to move toward a personalized medicine approach instead of a one-size-fits-all approach to the treatment of eating disorders.
Only with the participation of people who have experienced eating disorders at any point in their lives can we achieve our goal of eliminating these devastating illnesses.
Learn more about the Eating Disorders Genetics Initiative and how to participate.