BY Helena L Davies (from the 2020 archive)
February 2020 has seen the launch of the Eating Disorders Genetics Initiative (EDGI). This project is the result of a collaboration between King’s College London, Beat (the UK’s eating disorder charity), and the National Institute for Health Research (NIHR). By collecting genetic, psychological, and clinical data from those who have experienced any eating disorder, it is hoped that we can improve our understanding of the causal influences on these devastating and sometimes lethal disorders. Helena Davies spoke to Professor Gerome Breen, the Chief Investigator of EDGI, about what the project means for eating disorders research.
What are the key aims behind EDGI?
Eating disorders are a lot more prevalent than people realise. On a lifetime basis they affect about 5% of the population. However, research into eating disorders is not very well funded. Eating disorders weren’t actually well recognised as clinical entities until the 1980s, and unfortunately research has not yet caught up with other disorders such as depression or schizophrenia. Essentially, in eating disorders research, we need to make it cheaper to conduct clinical trials and studies of environmental interventions or other interventions. To do this, we are setting up EDGI which has two aims. First, we want to find genetic variants and understand the genetic interaction with the environment for different eating disorders. Second, we then want to create a large, re-contactable database of participants – people with experience of eating disorders who can then be recontacted to take part in studies. This is particularly important in anorexia nervosa and bulimia nervosa, because recurrent episodes account for the bulk of the mortality associated with those disorders.
Eating disorders weren’t actually well recognised as clinical entities until the 1980s, and unfortunately research has not yet caught up with other disorders such as depression or schizophrenia.
What are the different roles of the organisations involved and how is the study going to work?
The study is funded by the NIHR and is part of a national initiative called the NIHR Bioresource. In essence, [the NIHR Bioresource aims] to make translational medicine and clinical trials as cost-effective as possible across all specialities of medicine. What we do [at King’s College London], is lead the mental health component of that. In the last year we’ve been leading quite a successful study called GLAD (Genetic Links to Anxiety and Depression Study). EDGI follows a similar design. We want to use social media and other forms of media to advertise the study. We do some checks to verify that someone has probably had an eating disorder and if they meet the criteria then we send them a saliva kit in the post. The saliva kits are a nice orange colour because we are collaborating with Beat. Once people get the saliva kit, they fill it and send it back. It goes to a central lab run by the NIHR and that sample is then processed into DNA. What happens to that DNA is interesting – genetic technology has advanced enormously in the last decade so we can now, in basic terms, get information on 7-10 million genetic variants for less than £50 per person. And that’s exactly what we’re going to do in EDGI. Taking all that genetic data, we will merge it with the phenotypic data – the information on symptoms and diagnoses and comorbidities – and that will allow us to conduct various types of analyses. So, we’ll work with large international projects trying to discover genetic variants associated with each ED. We’ll conduct specific analyses looking at how genetic risk across the genome interacts with known environmental risk factors, such as trauma, or other eating disorder-specific factors.
Is there anything from GLAD that you’ve learned either to do the same or to do differently with EDGI?
GLAD has been immensely useful. It’s helped us to optimise our processes. However, the biggest thing about GLAD is that the questionnaire was rather long, it takes about 40-45 minutes if someone is quite comorbid. For example, if they’ve had a couple of different types of anxiety and quite a few episodes of depression. So, part of the goal in EDGI was to make the main questionnaire a little bit simpler, a little bit more attractive, as it were, to participants. We still allow people to give us lots of information and have optional questionnaires so if people want to contribute more, they can.
Why is it important to disentangle the environmental and genetic causes of eating disorders? What do you imagine the clinical applications will be?
There are a few things. One is that we have this idea, and we use the words all the time: “environmental or genetic”, when actually every environmental risk factor that you look at has its own heritability and genetic basis, and every genetic factor you look at has its own environmental basis as well. It’s very complex, and we need to move beyond this if we want to make progress in discovering new therapies for eating disorders, which have so far advanced very slowly. One of the problems in eating disorders research is that detailed information, such as environmental risk factors or neuroimaging or genomics, has only been done in tiny samples. Now the thing about genomics is that it is cheap to do, so we can do it in a large sample. And the thing about environmental surveying for risk factors is that we can do some of that via questionnaires. Our idea is to combine both of them and to recruit people and simultaneously assess their environmental risk and their genetic risk. That will allow us to take the next step beyond just discovery of genetic variation or just discovery of environmental risk factors. Hopefully, once EDGI and similar studies accrue a certain sample size, we can actually show which environmental risk factors interact with genetic risk. One simple idea would be that it’s those environmental risk factors that are intervenable; we could use environmental interventions to dampen down genetic risk.
…every environmental risk factor that you look at has its own heritability and genetic basis, and every genetic factor you look at has its own environmental basis as well.
Why do you think people with eating disorders are keen to participate and what difficulties do you expect to encounter?
We’ve seen previously in other recruitment efforts that we don’t get any shortage of people who want to participate. There are some barriers though to people joining. For example, sometimes people are too ill, so sometimes we don’t get the full spectrum of participants. I’m slightly concerned that we might not get as many people with binge-eating disorder as with anorexia, but we will have to see. We will vary our recruitment strategies, so go via social media but also go and collaborate with various clinical centres to make sure that we get a good representation of the population with eating disorders. Particularly in those with more of binge-eating disorder presentation, they may have other issues such as depression or anxiety that might make it more difficult for them to join the research.
EDGI is different to ANGI (Anorexia Nervosa Genetics Initiative) because it includes bulimia and binge eating disorder. Why is this important?
Anorexia nervosa is the most prominent eating disorder, but it only affects rather less than 1/5 with an eating disorder diagnosis. It’s important to remember that binge-eating disorder and bulimia nervosa and newer things, like Avoidant Restrictive Food Intake Disorder (ARFID), are important disorders. If anorexia nervosa has been under-researched, which it has, then these disorders have barely been touched by a lot of research, except for relatively small sample size research. We’ve shown convincingly that in schizophrenia and depression, and even now in anorexia nervosa, that once we get large samples together, we can make interesting discoveries. One of the things we’ve been able to show with anorexia nervosa is that its genetics may be partially metabolic. It’s going to be interesting to study all three. We know that anorexia nervosa seems to have a genetic-metabolic basis, but will we see the same picture in bulimia nervosa and binge-eating disorder? Perhaps not, or perhaps we will. We have to get to the sample sizes that we need.
If anorexia nervosa has been under-researched, which it has, then these disorders [bulimia and binge-eating disorder] have barely been touched by a lot of research.
What sample size are you aiming for? What is your expected timeline?
We’re aiming for 5,000 participants in the first year, and maybe 10,000 participants overall by the end of 3 years. In reality, if EDGI works well, then we would hope to be able to continue, funding allowing.
For people reading this, what can they do to help EDGI on its way?
If they have had an eating disorder themselves, they could join EDGI. If they have not, they should keep an eye on the EDGI website because we will also be launching an initiative to recruit healthy controls. If they could maybe retweet and like/share our posts on Facebook that would be much appreciated because the wider the reach we have, the more participants that we’ll get. Psychiatric disorders in general are very common, for example, if everyone in south London who had an eating disorder joined EDGI, we’d probably reach our recruitment goal in half a day flat, but it’s just how you reach people. I suppose another issue is, will we reach each group equally? That’s another thing we need to think about.
…if everyone in south London who had an eating disorder joined EDGI, we’d probably reach our recruitment goal in half a day flat.
Finally, what are you most excited about for EDGI?
Getting it up and running, there’s probably pent-up demand out there for a project like EDGI, and I’m hoping that it will get people interested and excited in the research.