Celiac disease is linked to juvenile idiopathic arthritis (JIA) in children and rheumatoid arthritis (RA) in adults, according to an analysis of nationwide data in Sweden.
“I hope that our study can ultimately change clinical practice by lowering the threshold to evaluate celiac disease patients for inflammatory joint diseases,” John B. Doyle, MD, a gastroenterology fellow at Columbia University Irving Medical Center in New York, told this news organization.
“Inflammatory joint diseases, such as JIA and RA, are notoriously difficult to diagnose given their variable presentations,” he said. “But if JIA or RA can be identified sooner by physicians, patients will ultimately benefit by starting disease-modifying therapy earlier in their disease course.”
The study was published online in The American Journal of Gastroenterology.
Analyzing associations
Celiac disease has been linked to numerous autoimmune diseases, including type 1 diabetes, autoimmune thyroid disease, lupus, and inflammatory bowel disease (IBD), Dr. Doyle noted. However, a definitive epidemiologic association between celiac disease and inflammatory joint diseases such as JIA or RA hasn›t been established.
Dr. Doyle and colleagues conducted a nationwide population-based, retrospective matched cohort study using the Epidemiology Strengthened by Histopathology Reports in Sweden. They identified 24,014 patients diagnosed with biopsy-proven celiac disease between 2004 and 2017.
With these data, each patient was matched to five reference individuals in the general population by age, sex, calendar year, and geographic region, for a total of 117,397 people without a previous diagnosis of celiac disease. The researchers calculated the incidence and estimated the relative risk for JIA in patients younger than 18 years and RA in patients aged 18 years or older.
For those younger than 18 years, the incidence rate of JIA was 5.9 per 10,000 person-years among the 9,415 patients with celiac disease versus 2.2 per 10,000 person-years in the general population, over a follow-up of 7 years. Those with celiac disease were 2.7 times as likely to develop JIA.
The association between celiac disease and JIA remained similar after adjustment for education, Nordic country of birth, type 1 diabetes, autoimmune thyroid disease, lupus, and IBD. The incidence rate of JIA among patients with celiac disease was higher in both females and males, and across all age groups studied.
When 6,703 children with celiac disease were compared with their 9,089 siblings without celiac disease, the higher risk for JIA in patients with celiac disease fell slightly short of statistical significance.
For those aged 18 years or older, the incidence rate of RA was 8.4 per 10,000 person-years among the 14,599 patients with celiac disease versus 5.1 per 10,000 person-years in the general population, over a follow-up of 8.8 years. Those with celiac disease were 1.7 times as likely to develop RA.
As with the younger cohort, the association between celiac disease and RA in the adult group remained similar after adjustment for education, Nordic country of birth, type 1 diabetes, autoimmune thyroid disease, lupus, and IBD. Although both men and women with celiac disease had higher rates of RA, the risk was higher among those in whom disease was diagnosed at age 18-59 years compared with those who received a diagnosis at age 60 years or older.
When 9,578 adults with celiac disease were compared with their 17,067 siblings without celiac disease, the risk for RA remained higher in patients with celiac disease.
This suggests “that the association between celiac disease and RA is unlikely to be explained by environmental factors alone,” Dr. Doyle said.