In eating disorder clinics, I’ve met several patients who have both diabetes and an eating disorder, or (less often) an eating disorder and Coelic Disease or Crohn’s, and it certainly increases the complexity of treating both conditions. Of course, some people just happen to have more than one illness, but it makes you wonder: are they related? If they are, which came first? And, of course, does it matter either way?
Autoimmune conditions, where the body starts attacking its own cells, cover a multitude of systems; the ones this paper focuses on are Coeliac Disease, Crohn’s, Ulcerative Colitis (UC), Diabetes Mellitus (Type 1), Psoriasis, Lupus and Arthritis, but this is not a conclusive list. Like eating disorders, they’re more common in women.
Here’s one argument for how (at least some) autoimmune diseases might lead to eating disorders: if you’re having to manage your diet (say, because you have diabetes or Coeliac) or a combination of your illness and its treatment leads to you losing or gaining weight (Crohn’s, UC), this may make you very focused on your diet and weight, and potentially feel very negative about your body. We know that body dissatisfaction is a risk factor for eating disorders (Jacobi et al, 2004), and indeed previous work has found that these autoimmune diagnoses do increase the risk for subsequent eating disorders. (ref Francesca Solmi’s blog).
It is also possible that eating disorders may increase the risk of autoimmune diseases, though how that could happen mechanistically is less clear. Probably the most likely explanation would be that there is some other risk factor underlying both conditions; the authors suggest dysregulated immune function as a candidate for this.
Before we get too caught up in mechanistic speculation, we need to see first of all if there is a relationship, and if so which direction it goes in, and that is what this new paper (hot off the press today in the Journal of Child Psychology and Psychiatry) kindly does (Hedman et al, 2018).
Which came first? The eating disorder or the autoimmune disease?
Methods
Ah, thank goodness for the lovely Scandinavian population’s willingness to have their data open and linked up. The researchers have used this well, linking up registers on birth year, sex, migration, cause of death and socio-economic status, as well as health records on eating disorders and autoimmune conditions. Studying 0-35 year-olds born between 1979 and 2005, gave them just over 2.5 million people’s records, or 33 million-and-some person-years.
Then they did some Cox proportional hazards modelling to work out how likely people with an eating disorder are to get an autoimmune condition compared to those without an eating disorder, and how likely people with an autoimmune condition are to get an eating disorder, compared to those without an autoimmune condition.
The eating disorder outcomes they used were Anorexia Nervosa, “Other Eating Disorder” which lumps in Bulimia, Eating Disorders Not Otherwise Specified and Binge Eating Disorder, and “Any Eating Disorder” (any of the above). They added in bulimia nervosa as a separate diagnosis, but the numbers were small and they considered it a “secondary analysis”. They tried to look at men as well as women which is always tricky because the numbers get small. Autoimmune diseases were also lumped together as “any autoimmune disease” and divided up diagnosis by diagnosis.
Results
Autoimmune disease and subsequent eating disorders
- “Any autoimmune disease” was associated with increased risk of subsequent “any eating disorder” in
- Males (HR 1.78 (95% CI 1.40 to 2.26), p<0.001) and
- Females (HR 1.62 (95% CI 1.53 to 1.72), p<0.001)
- In males, breaking it down into individual autoimmune diseases/eating disorders makes numbers too small to be meaningful
- In females it looks like most autoimmune diseases (except interestingly arthritis) are associated with subsequent increased risk of eating disorders. The hazard ratios are biggest for Type 1 Diabetes (HR 2.19 (95% CI 1.96 to 2.46), p<0.0001 for any eating disorder).
Eating disorders and subsequent autoimmune disease
- In females, “any eating disorder” was associated with subsequent increased risk of any autoimmune disease (HR 1.53 (95% CI 1.42 to 1.65), p<0.001); this association was not found in males (probably a numbers-are-too-small problem)
- In males, breaking it down into subgroups is in my opinion probably not worth doing, as the numbers get even smaller.
- In females, there are convincing associations between:
- Anorexia Nervosa and subsequent Coeliac disease (HR 1.83 (95% CI 1.40 to 2.39), p<0.001)
- “Other Eating Disorders” and subsequent:
- Coeliac disease (HR 1.69 (95% CI 1.32 to 2.17), p<0.001)
- Crohn’s disease (HR 1.72 (95% CI 1.33 to 2.22), p<0.001) and
- Psoriasis (HR 1.38 (95% CI 1.13 to 1.68), p=0.002)
- “Any Eating Disorder” and subsequent:
- Coeliac disease (HR 1.72 (95% CI 1.40 to 2.10), p<0.001)
- Crohn’s disease (HR 1.63 (95% CI 1.31 to 2.03), p<0.001), and to a lesser extent
- Ulcerative Colitis (HR 1.28 (95% CI 1.02 to 1.61), p=0.03)
- Arthritis (HR 1.37 (95% CI 1.04 to 1.82), p=0.03) and
- Psoriasis (HR 1.25 (95% CI 1.04 to 1.49), p=0.02).
This study shows a strong, bidirectional relationship between eating disorders and autoimmune diseases, indicating that diagnosis in one illness class increased the risk of the other.
Conclusions
The authors conclude that there is a bidirectional relationship between autoimmune conditions and eating disorders, and go on to discuss the possibility of a common underlying risk factor for the two. I am not entirely convinced that this is definitely the explanation – read on to find out why…
Strengths and limitations
Scandinavia does many, many things well, including crime thrillers, pickled fish, midnight sun and (perhaps most relevant to this blog) data linkage. The large sample sizes provided by this data are very useful in epidemiology and are a big strength of this paper.
However, there are some limitations when it comes to interpretation. I think the main one which is critical here is that you have to present to secondary (specialist) services and get a diagnosis to get counted. This is a bit of an issue with eating disorders, although we don’t have data from Sweden, we do know that only 28-56% of people with an eating disorder get treated (Smink et al, 2014;Swanson et al, 2011). This is important because you might be more likely to get your eating disorder spotted and treated if you turn up in clinic with an autoimmune condition; so the autoimmune condition leading to eating disorder could be a red (possibly pickled) herring. Similarly, if you do turn up in an eating disorder clinic, good clinicians will start following evidence-based guidelines like these (shameless plug for my BMJ article), and before you know it, a thorough history and some screening blood tests may have led to your previously-undiagnosed Coeliac or Crohn’s Disease being spotted. To my mind, the results the authors present on the “temporal proximity” of the diagnoses (the associations are strongest when diagnoses occur within one year of each other) suggests that this explanation may explain at least a proportion of the findings.
This is not to say that the authors may not be right: there may be some shared underlying cause of both eating disorders and autoimmune conditions, and we should research this further. It’s just that the case isn’t closed yet.
There’s more detective work to do. We elves are strongly in favour of handing Saga Norén the case.
Implications for practice
Whether or not there is an association between eating disorders and autoimmune conditions isn’t just a matter for idle speculation. Immediate implications for practice are that clinicians across medical specialties need to be alert to their patients with autoimmune diseases having or developing eating disorders, and those in psychiatry need to be alert to the possibility of various autoimmune conditions in their patients.
In the longer term, if the authors are right, the potential that this association is due to dysregulated immune system function gives rise to the possibility of finding novel treatment targets, which would be fantastic news for patients with eating disorders.
Clinicians should be alert to their patients with autoimmune diseases having or developing eating disorders, and mental health professionals need to consider the possibility of various autoimmune conditions in their eating disorder patients.
Conflicts of interest
None
Links
Primary paper
Hedman A, Breithaupt L, Hübel C, Thornton LM, Tillander A, Norring C, Birgegård A, Larsson H, Ludvigsson J, Sävendahl L, Almqvist C, Bulik CM. (2018), Bidirectional relationship between eating disorders and autoimmune diseases. J Child Psychol Psychiatr. https://doi.org/10.1111/jcpp.12958
Other references
Jacobi C, Hayward C, de Zwaan M, Kraemer HC, Agras WS. (2004) Coming to terms with risk factors for eating disorders: application of risk terminology and suggestions for a general taxonomy. Psychological bulletin. 2004;130(1):19-65. [PubMed abstract]
Autoimmune and autoinflammatory diseases associated with higher risk of eating disorders
Smink FR, van Hoeken D, Oldehinkel AJ, Hoek HW. (2014) Prevalence and severity of DSM-5 eating disorders in a community cohort of adolescents. The International journal of eating disorders. 2014;47(6):610-619. [PubMed abstract]
Swanson SA, Crow SJ, Le Grange D, Swendsen J, Merikangas KR. (2011) Prevalence and correlates of eating disorders in adolescents: Results from the national comorbidity survey replication adolescent supplement. Archives of general psychiatry. 2011;68(7):714-723.
Bould H, Newbegin C, Stewart A, Stein A, Fazel M. (2017) Eating disorders in children and young people. BMJ. 2017;359.
Photo credits
- Photo by MILKOVÍ on Unsplash
- Photo by Gaelle Marcel on Unsplash
- Photo by Chris Yang on Unsplash
- Photo by Kev Costello on Unsplash
I am a patient with Type 1 diabetes (Mine is type 1 youth onset, not type 2 that became type 1, fyi. Those are actually two different disorders with different causes, but similar symptoms.) AND I have severe UC that has been diagnosed as Pancolitis. In other words, my digestive system is a trainwreck. I have both of the disorders you named in your research.
Have you ever heard of the BRAT diet? That’s a temporary diet where you eat only Bananas, Rice, Applesauce and Toast, often used to calm the digestive system in patients like me with tendencies towards gastrointestinal distress. My diet is so limited, I can safely eat TWO of those things. If I eat apple anything or toast, chances are high I’ll end up doing something I describe as ‘puking blood out both ends’, and then I’ll go back to the hospital. (I’ve been hospitalized 4 times in 2 years for extreme dehydration, pain, and internal bleeding, even WITH proper disease management.)
Having UC and diabetes is like living with a manipulative, and highly arbitrary abuser who randomly punishes you based on what you eat. No matter what you eat, the likelihood is high that, eventually, it will start making you have a bad reaction. Eating equals PUNISHMENT. The rules change about what you can eat, too, sometimes overnight. See, the more you limit yourself, the more likely it is you will eat more of what you still CAN eat, increasing the chances you’ll develop a pretty much permanent reaction to one of those things, too. It’s a neverending cycle of food-related pain and trauma, new and seemingly arbitrary rules about food, and then more food-related trauma.
The behaviors that are criteria for eating disorder diagnosis (avoiding eating with others, avoiding eating for extended periods, overeating – whenever I CAN eat-, obcessive thoughts about what to eat and how to eat it, low body image aka ‘my body is a lemon’, extreme weight loss or gain) these are all as a result of trying to manage the traumatic, life-interrupting and very real symptoms of two serious, chronic digestive disorders for me. I keep 4 different sizes of clothing in my closet as a result, all the same few extremely basic outfits to keep the cost down. I’m reacting to very real things, here, though, not psyching myself out. My body is a warzone, a lemon, a trainwreck. If I could trade it in like people do with used cars, I’d do it in a second.
Do I have an eating disorder, too? I don’t know about that. If you refuse to drink poison and avoid situations where you might be pressured to drink poison, mostly because poison will make you sick, then that seems like a pretty mentally healthy decision to me. I do that same thing with food because so many perfectly normal foods can make me extremely ill.
People tend not to understand, because it IS complicated. If I have to go to a social event where there will be food, I just tell them, ‘I have a lot of food allergies, so I’ll eat before I come,’ so I don’t have to give a lengthy lecture involving me pooing and puking and bleeding and getting hospitalized when all they did was invite me to a baby shower. (Um… ew!) I also know that if I go, and they inevitably try to insist I eat at the event, then I’ll have to grill them about ‘what’s in that cassarole?!’ It comes across like I’m accusing them of trying to poison me, when all they wanted was for me to try some of the food they spent hours preparing.
It’s usually easier to skip any social event that might involve eating. Most social events involve eating, so… I stay home. I hang out with my bestest-best friend, the #!$&ing toilet.
Point is, the ‘eating disorder’ behaviors in people like me are in response to real trauma. This is not a mental disorder due to extreme social pressure to be thin, or a pathological response to a lack of control over our lives. It”s true that we really don’t have control, of course. UC and diabetes have stolen every iota of our control.
If the doctors called me up tomorrow and said, ‘Guess what, kid? We found the cure!’ I would go get that cure no matter the cost, and then, I would visit every restaurant in town to wolf down everything I have been forced to miss. Twice. The cure for UC would probably kill me.
You ask me, I say that people with severe, chronic digestive disorders like myself, are more likely suffering from food/digestive associated PTSD. Someone says, ‘Look what I cooked for you! It’s gluten free!’, and all I want to do is crouch under the table and shiver with terror.
It’s like the guy who comes back from the war who freaks out every time someone sets off a firework. In the war, he likely learned that explosions meant trauma, loss, pain. If his reaction to the trigger, in this case the sound of gunshots or explosions, is extreme, then it might be reasonable to diagnose him with PTSD.
In the ongoing war inside my body, I have learned that eating food equals trauma, loss and pain, too. Hence, I have extreme reactions to my trigger, even if mine is a mysterious cassarole with unknown ingredients at a baby shower.
The difference here is that, like all humans, I NEED to eat. The guy with PTSD from the war can mostly avoid his trigger. He won’t die if he skips the fireworks show, avoids movies depicting violence, moves to a quiet neighborhood, etc. He will obviously be more at risk for certain problems due to the mental injury the trauma caused, but there are steps he can take toward healing, toward avoiding reopening old wounds. I would assume his doctors would focus on healing him as much as possible via medication and counseling, and teaching him ways handle it better when he does have to face his trigger.
I can’t avoid mine. Ever. Food is everywhere. My trauma gets reinforced every time I eat, if I even have to LOOK at food. Hardees comercials retraumatize me to the point I’ve had to stop watching cable TV. (God I’m so hungry! Look at that big, beautiful sandwich! … Nope. That thing’ll kill me. Remember that time I broke down and tasted my friend’s Arby’s cheese stick? It was sooooo good, too, but afterwards there was the week I spent in the hospital, the unending pain, the blood, the endless needles, the endocope, the cost of missing work and all the insane medical bills? I’m literally still paying off the price of that one bite of Arby’s cheesestick I took three years ago. Nope. Nope. Nope. Can’t afford it. Don’t want it. I’ll force down some plain rice later, but for now, I suddenly don’t feel so hungry anymore.) This is what’s going on in MY head when the food commercials come on TV, anyways, thanks to UC symptoms and diabetes looming over my every waking moment.
If I don’t eat, I know I will die. Obviously. If I do eat, though, with UC especially, there’s a very real chance I will go through extreme, extended suffering. Hard choice, that. I sit down to eat my once daily meal, and it feels more like sitting down to gamble where the odds are against me. The dice are loaded. The cards are counted. It’s not a matter of if I will lose this game, it’s when I will lose, and how much.
Eating disorder? I feel compelled to disagree. If it is an eating disorder, it is a rare subtype more closely related to PTSD than something like anorexia, even if the outward symptoms are similar.