The risk of developing autoimmune thyroid disease (AITD) is 7 times higher among juvenile idiopathic arthritis (JIA) patients with family history of AITD, according to a study published in Pediatric Rheumatology.¹ Female patients who were antinuclear antibody (ANA) positive were also at a greater risk of AITD.

Researchers from Italy, France, Russia, Israel, Austria, Mexico and The Netherlands, analysed data of 8965 JIA patients (68.1% girls) from the International Pharmachild registry with the aim to find out factors that were predictive of symptomatic AITD including nonspecified AITD, Hashimoto thyroiditis and Graves’ disease. The Pharmachild registry includes JIA patients from 85 Paediatric Rheumatology International Trials Organisation (PRINTO) centers from across the world.

Ninety-six (1.1%) of the 8965 patients were found to have AITD after a median follow-up period of 5.5 years. Fifty-eight of them had Hashimoto’s thyroiditis (60.4%), four had Graves’ disease (4.2%), while in the remaining 34 patients, AITD was unspecified (35.4%). Results of multivariable analysis revealed that the risk increased 2-folds among female patients with odds ratio (OR) of 2.2 and those who were ANA positive (OR 2.0). The prevalence of AITD was higher in female patients than in male patients (83.3% vs. 68.0%, respectively) and in those who were ANA (55.7% vs 41.5%) and rheumatoid factor (RF) (10.0% vs 4.3%) positive. The occurrence of AITD was higher among patients who developed JIA at a median age of 7.8 years compared to those in whom the disease onset was at 5.3 years. Patients who had a family history of AITD were nearly 7 times more likely to develop AITD with OR of 6.8. The incidence of AITD in these patients was 27.5% compared to 4.8% of those who did not have a family history (4.8%). Patients with a positive family history of AITD were more likely to develop AITD (The incidence of AITD was higher among patients with polyarthritis (40.6% vs. 30.4%).

Active joint count, indicative of disease activity, at the time of diagnosis of JIA was similar between patients with AITD and those without. Growth retardation and/or short stature were also comparable between the two groups. However, patients with AITD had higher incidence of diabetes (2.1% vs. 0.3%) and celiac disease (4.2% vs 0.6%) compared to those who did not have AITD. The researchers note that “16 female ANA positive JIA patients with a family history of AITD would have to be screened during ±5.5 years using standard blood tests to detect one case of AITD”.

This study has identified factors that increased the risk of AITD among patients with JIA. Those who develop AITD tended to be older in age and they also had higher incidence of polyarthritis, ANA positivity and a family history of AITD. Being female also increased the likelihood of developing AITD. Hence, children with JIA, especially girls, at high risk should undergo annual serological screening for AITD.

Reference

1. Joeri W van Straalen, et al; Paediatric Rheumatology International Trials Organisation (PRINTO). Juvenile idiopathic arthritis patients with positive family history of autoimmune thyroid disease might benefit from serological screening: analysis of the international Pharmachild registry. Pediatr Rheumatol Online J. 2023 Feb 21;21(1):19. doi: 10.1186/s12969-023-00802-1.