NATIONAL HARBOR, MD. — Children with inflammatory bowel diseases have a significantly increased risk for other immune-mediated diseases, according to a large cross-sectional study.
Previous studies in adults have demonstrated associations between inflammatory bowel disease (IBD) and comorbid rheumatologic, autoimmune, and atopic conditions, but this is the first population-based study to examine those links in children with inflammatory bowel diseases, Dr. Michael Kappelman said at the annual meeting of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN).
The associations between pediatric IBD and both rheumatoid arthritis and lupus were particularly strong, and of a higher magnitude than previously demonstrated in studies of adult IBD comorbidity. “The burden of IBD in children is quite substantial and involves not only the gastrointestinal burden but also the extraintestinal burden, including comorbidities,” Dr. Kappelman, a pediatric gastroenterologist at the University of North Carolina at Chapel Hill, said in an interview.
“When managing these children, you have to maintain a high level of suspicion for associated conditions.” The study involved an administrative data analysis of 1,242 children with IBD and 3,353 matched controls who were enrolled continuously in 87 health plans in 33 states during 2003-2004. They had a mean age of 15 years, and slightly more than half (55%) were male.
The study sample included 737 children with Crohn's disease and 488 with ulcerative colitis. Each child with IBD was matched with three controls on the basis of age, sex, health plan, and geographic region.
Eight specific immune-mediated comorbid diagnoses were examined, grouped into four categories: rheumatologic (rheumatoid arthritis and lupus); autoimmune (type 1 diabetes and hypothyroidism); atopic (asthma, eczema, and allergic rhinitis); and other inflammatory (psoriasis).
The strongest relationship with IBD was seen with lupus, with an odds ratio of 21.7, compared with controls. Rheumatoid arthritis was also significantly greater among the IBD children, with an odds ratio of 9.6. The relationship with both RA and lupus was statistically significant for children with Crohn's, while not quite reaching statistical significance for those with ulcerative colitis.
In contrast, the odds ratios for the association between IBD and rheumatoid arthritis from three adult studies ranged from 1.4 to 2.4, while one study looking at IBD and lupus in adults showed an odds ratio of just 1.3.
There was also an elevated risk for autoimmune disorders among the children with IBD, with odds ratios of 2.6 for hypothyroidism and 1.9 for type 1 diabetes. The associations reached statistical significance for Crohn's disease and thyroid disease and for ulcerative colitis and diabetes. Weaker associations were seen with the atopic conditions, with odds ratios of 1.1 for asthma, 1.3 for eczema, and 1.3 for allergic rhinitis. The associations between Crohn's and ulcerative colitis and Crohn's and allergic rhinitis did reach statistical significance, but just barely. The association was insignificant for psoriasis, with an odds ratio of 1.2.
In contrast to the rheumatologic disorders, studies of adults with IBD have found associations of similar or slightly greater strength than among children with the other immune-mediated disorders, including odds ratios of 1.1-1.3 for hypothyroid disease, 1.4-1.5 for asthma, and 1.5-1.7 for psoriasis.
The reason for the adult-child differences isn't known. “Obviously it has something to do with the disease etiology and pathogenesis, which is currently a black box. We talk about early-onset disease being different from later-onset disease. Moreover, [Crohn's] and [ulcerative colitis] are probably not 2 diseases but more like 50 different diseases. Right now we're just not sophisticated enough to subtype appropriately,” he said.
This study was funded in part by a grant from the National Institutes of Health. Dr. Kappelman stated that he had no relevant financial disclosures.