Celiac disease is an autoimmune disorder triggered by dietary gluten in genetically predisposed individuals. Gluten is a protein found in wheat and related grains such as barley and rye. The disease affects one to two percent of Western populations.
An international team of physicians conducted a nationwide cohort study of the Swedish population to explore the relationship between childhood celiac disease and subsequent psychiatric disorders, including ADHD, as well as suicide attempts and suicide.
With data from all 28 pathology departments in Sweden, they identified all 19,186 children with a diagnosis of biopsy-verified celiac disease from 1973 through 2016, and no previous history of psychiatric disorder. They then matched them with 94,249 children controls matched for age, sex, county, and calendar year from the Swedish national registers that encompass the entire resident population.
To address shared intrafamilial confounding, including genetic and early environmental factors, the team also compared 13,015 individuals with celiac disease with their 18,024 non-celiac siblings.
Additional Swedish national registers (Patient Register, Cause of Death Register) then made it possible to link the preceding data with data on subsequent psychiatric disorders and suicides for all the children in the study.
Celiac disease diagnosed in childhood was associated with a 19 percent higher risk of any subsequent psychiatric disorder at any time than for controls. The greatest spike in risk - 70 percent higher than for non-celiac controls - was in the first year following diagnosis of celiac disease. Restricting follow-up until the age of 18 years, celiac disease was linked to a 26 percent increased risk of any psychiatric disorder. For adults 18 and over, the increased risk declined to just 11 percent. So an initial sharp spike was followed by a steeply declining curve over time.
For ADHD, the increased risk at any time after the diagnosis of celiac disease was 29 percent. That compares with 47 percent for autism spectrum disorder, 34 percent for eating disorders, 20 percent for mood disorders, and 12 percent for anxiety disorders. There was no increased risk of psychotic disorders, behavioral disorders, personality disorders, psychoactive substance abuse, suicide attempts, or suicide. For adults 18 and over, however, the increased risk of ADHD rose to 39 percent, second only to autism spectrum disorder. For these two psychiatric conditions, there was an upward curve rather than a declining one.
The sibling analyses found a reduced but still significant 12 percent increased risk of psychiatric disorder following a diagnosis of celiac disease, again with the first-year spike of 48 percent increased risk declining to insignificance for the period beginning five years later. For ADHD, the increased risk also descended to 12 percent, but became non-significant, suggesting the increases were primarily attributable to confounding variables.
Among the 2,071 children with celiac disease who had a follow-up biopsy that showed mucosal healing of the small intestine in response to a gluten-free diet, the association with subsequent psychiatric disorders vanished.
The authors speculated that the spike in psychiatric diagnoses in the year following diagnosis of celiac disease could be because "the systemic inflammatory response is mediating this relationship," or could be due to "the psychosocial stress associated with adapting to the gluten-free diet." "However," they cautioned, "this risk is unlikely to be due to the gluten-free diet alone since we also observed an increased risk of psychiatric disorders preceding the diagnosis of celiac disease, possibly related to the systemic inflammatory response described above." We must also keep in mind that such studies cannot rule out all sources of confounding or the possibility that being diagnosed with celiac disease leads to more exposure to the healthcare system and more opportunities for a diagnosis of ADHD to be recognized.
Benjamin Lebwohl, MD, Linnea Haggård, MD, Louise Emilsson, MD, PhD, Jonas Söderling, PhD, Bjorn Roelstraete PhD, and Agnieszka Butwicka,MD, Peter HR Green, MD, Jonas F.
Ludvigsson, MD, Ph.D., "Psychiatric disorders in patients with a diagnosis of celiac disease during childhood from 1973 to 2016," Clinical Gastroenterology and Hepatology (2020), https://doi.org/10.1016/j.cgh.2020.08.018.
_logo%201.svg)
