Early diagnosis important for effective treatment
By Amy Ratner, director of scientific affairs
Children and adults with celiac disease have an increased risk of autoimmune arthritis compared to the general population, according to a new study based on Swedish health records.
Children with celiac disease were three times as likely to subsequently develop juvenile idiopathic arthritis and adults were twice as likely to be diagnosed with rheumatoid arthritis compared to controls, researchers from the Celiac Disease Center at Columbia University and colleagues at two Swedish institutions found.
About 24,000 celiac disease patients were compared to about 118,000 matched controls, which study authors suggest is the largest investigation of the association between celiac disease and the two types of arthritis. The study, published recently in the American Journal of Gastroenterology, is also the first to base findings on a combination of biopsies and diagnostic codes in health records.
Of nearly 9,500 children diagnosed with celiac disease younger than 18 years of age, 40 developed juvenile idiopathic arthritis during seven years of follow up compared to 73 in a control group of about 47,000. This translates into 5.9 per 10,000 people years among children with celiac disease compared to 2.2 in the general population.
Meanwhile, of more than 14,000 adults diagnosed with celiac disease after the age of 18, 110 developed rheumatoid arthritis during nearly nine years of follow up compared to 322 in the control group of about 71,000, an incidence rate of 8.4 per 10,000 people years compared to 5.1 people years.
Person years are a measurement that considers both the number of people in the study and the amount of time each person spends in the study.
Celiac disease patients who have inflammatory joint symptoms should be evaluated for juvenile idiopathic arthritis or rheumatoid arthritis, the study concludes. Authors call for a “low threshold” for this testing because these forms of arthritis have varying disease courses and early diagnosis can identify patients who can benefit from treatment.
Additionally, they wrote, patients with both celiac disease and juvenile idiopathic arthritis can have a more severe course than those who don’t have celiac disease.
In autoimmune arthritis a person’s own immune system attacks their joints. It is distinguished from osteoarthritis, which is caused by mechanical wear and tear on joints.
Researchers identified patients diagnosed with celiac disease with a biopsy between 2004 and 2017 by using one Swedish data base. They then linked to the Swedish National Patient Registry, which has inpatient and outpatient healthcare data that dates from 2001, to determine who was also classified as having been diagnosed with juvenile or rheumatoid arthritis.
In children, both boys and girls with celiac disease had a higher incidence of having juvenile arthritis than the general population and the increased rate occurred across ages. In adults, women with celiac disease, who made up the majority of those included in the study, had a higher incidence rate of rheumatoid arthritis compared to men with celiac disease and the general public.
The authors note that while the prevalence of celiac disease in those with juvenile arthritis has been previously investigated, although with conflicting results, few studies have assessed the risk of juvenile arthritis in those who have celiac disease.
The new study’s conclusion that autoimmune arthritis is found more often in children and adults with celiac disease compared to the controls was consistent when adjusted for multiple socioeconomic factors and other autoimmune diseases.
Additionally, some analysis of children who had been diagnosed with juvenile arthritis first led researchers to conclude that the risk seems to be increased both before and after a diagnosis of celiac disease making it difficult to determine if a timing relationship between the two conditions exists.
Likewise, separate analysis of adults diagnosed with rheumatoid arthritis first also found an increased risk of celiac disease compared to the general population.
Celiac disease and both juvenile and rheumatoid arthritis have shared genetic risks, the study says. Shared environmental risks, including infections and changes in the gut microbiome, may lead to increased permeability of the intestine and play a role in the development of celiac disease and rheumatoid arthritis, the authors wrote.
Overall, celiac disease is associated with a number of other autoimmune diseases, with thyroid disease and Type 1 diabetes among the most common.
Study participants came from a largely homogenous Swedish population, so findings are not necessarily generalizable to non-Nordic counties, the study says. The use of diagnostic codes presented the possibility of misclassification of diseases, but steps were taken to minimize this possibility, according to the study.
Researchers called for future studies to better understand what causes the association between celiac disease and these forms of arthritis and to explore treatment options.
You can read more about the study here.