Researchers have found new links between eating disorders and immune system diseases
that they say could help inform diagnosis and treatment.
“Our findings support compelling lines of evidence from researchers suggesting that
immune system disturbance is both comorbid with psychiatric disorders and can increase
risk for illness,” authors said in the study “Eating Disorders, Autoimmune, and Autoinflammatory
Disease” (Zerwas S, et al. Pediatrics. Nov. 9, 2017, https://doi.org/10.1542/peds.2016-2089).
Previous studies have found ties between autoimmune diseases and some psychiatric
disorders. Authors of this study expanded the research to include autoinflammatory
diseases and specifically looked at their links to eating disorders.
The team analyzed the records of nearly 1 million children and adolescents born in
Denmark between 1989-2006 and followed until 2012. During that time, 25,984 were diagnosed
with an autoimmune or autoinflammatory disease. Of those, 0.6% went on to be diagnosed
with an eating disorder.
Using Cox models to calculate hazard ratios, the team found children with an autoimmune
or autoinflammatory disease had a 50% higher hazard for an eating disorder — 73% higher
hazard for bulimia nervosa, 72% higher hazard for an eating disorder not otherwise
specified (EDNOS) and 36% higher hazard for anorexia nervosa.
Hazard levels were especially high for children with an autoimmune disease with gastrointestinal
involvement — 74% higher hazard for anorexia and 148% higher for EDNOS. Autoinflammatory
disease was linked to a 179% higher hazard for EDNOS.
Hazards were especially high for males. For instance, those with an autoinflammatory
disease had a 740% higher hazard for EDNOS, according to the study. However, researchers
cautioned confidence intervals were wide.
The team also found that of the 3,914 adolescents with an eating disorder, 2.1% had
a subsequent autoimmune or inflammatory diagnosis. Adolescents with anorexia had a
64% higher hazard for autoimmune/inflammatory disease, while those with EDNOS had
a 121% higher hazard.
Researchers could not say for certain why eating disorders and immune diseases are
linked, but offered theories.
“Eating disorders are commonly associated with reward dysfunction, and neural inflammation
can lead to changes in reward functioning including heightened reactivity to threat,
increased sensitivity to punishment, and decreased connectivity in reward pathways,”
The strong links between eating disorders and autoimmune diseases with gastrointestinal
involvement may be a matter of misdiagnosis for some adolescents due to symptoms overlapping,
but authors noted the associations held up even when there were no gastrointestinal
The team also found that adolescents with a family history of an autoimmune or autoinflammatory
disease were more likely to be diagnosed with an eating disorder. Parent-child, sibling
and cousin relationships all showed associations between the conditions, but it was
not clear whether the ties were due to genetics or environment.
Authors of a related commentary called the study a “significant contribution to the growing body of literature supporting
an association between immune system dysfunction and eating disorders.”
“Clinicians are encouraged to consider the possibility that patients with eating disorders
may have underlying autoimmune or autoinflammatory conditions,” they wrote. “… Conversely,
we must also remain vigilant about the development of eating disorders among patients
with autoimmune or autoinflammatory disorders.”