A recent study found first-degree relatives and spouses of individuals with celiac disease have increased risk for nonceliac autoimmune diseases.
“The prevalence of celiac disease is about 10% in first-degree relatives of celiac patients compared to about 1% in the general population. …However, very little is known about the risk of developing other autoimmune diseases in relatives of celiac patients," Louise Emilsson, MD, PhD, from Oslo University and primary care research unit, Värmlands Nysäter, told Healio Gastroenterology. “The main finding of the study is that both first-degree relatives (+28%) and spouses (+20%) are at increased risk of other autoimmune diseases.”
Aiming to determine the risk of several autoimmune diseases in first-degree relatives and spouses of patients with celiac disease, Emilsson and colleagues performed a nationwide, population-based, longitudinal cohort study in Sweden involving 29,096 patients with celiac disease and 144,522 controls matched for sex, county, age and birth year, all identified using national database records from 1969 to 2008. They also identified all first-degree relatives and spouses of the celiac patients (n = 84,648) and controls (n = 430,942) and calculated hazard ratios for Crohn’s disease, ulcerative colitis, type 1 diabetes mellitus, hypothyroidism, hyperthyroidism, psoriasis, rheumatoid arthritis, sarcoidosis and systemic lupus erythematosus.
After a median follow-up period of 10.8 years, 4.3% of celiac patient relatives and spouses had a nonceliac autoimmune disorder compared with 3.3% of relatives and spouses of controls. Compared with controls, celiac patient relatives (HR = 1.28; 95% CI, 1.23-1.33) and spouses (HR = 1.2; 95% CI, 1.06-1.35) had increased risk for nonceliac autoimmune diseases, both of which were statistically similar. The excess risk for nonceliac autoimmune diseases was 79 per 100,000 person-years in relatives and 63 per 100,000 person-years in spouses. Risk for developing a nonceliac autoimmune disease was greatest in the first 2 years after the celiac patient’s diagnosis (HR = 1.42; 95% CI, 1.28-1.57), but HRs were still significant after 2 years. Risk was higher in female spouses (HR = 1.33; 95% CI, 1.12-1.59) compared with male spouses (HR = 1.09; 95% CI, 0.92-1.29), but risk was not different between sexes among relatives. The highest HRs were for systemic lupus erythematosus, type 1 diabetes mellitus and sarcoidosis.
“There are several plausible explanations for these findings,” Emilsson said. “One is of course that individuals with celiac disease and their first-degree relatives share a genetic autoimmune predisposition. Another potential explanation involves shared environment (relevant for both first-degree relatives and spouses), but finally we cannot rule out that a certain degree of increased awareness of signs and symptoms in both first-degree relatives and spouses might lead to more examinations and thereby diagnoses (so-called ascertainment bias). Probably all of these mechanisms contributed to the finding. Clinicians could benefit from knowing that the genetic predisposition for celiac disease in celiac first-degree relatives also implies a higher risk of other autoimmune diseases.” – by Adam Leitenberger
Disclosure: The researchers report no relevant financial disclosures.
Editor's note: This article was updated on July 8 to reflect additional information.