OBJECTIVE: Given the multifactorial pathogenesis of juvenile spondyloarthritis (JSpA) and evidence of a protective effect in phenotypically similar diseases, we aimed to test whether breastfeeding is associated with the development and disease activity of JSpA.
METHODS: This single-center retrospective case-control study included children with JSpA and age- and sex-matched controls with a 1:1 ratio. Univariable and multivariable conditional logistic regression modeling for matched pairs was used to test the association of infant factors with the development of JSpA, including infant nutrition and form of delivery. Linear regression was used to assess the association of JSpA disease activity (JSpA Disease Activity Index with 6 elements [JSpADA6]) at presentation with breastfeeding exposure, form of delivery, and antibiotic exposure.
RESULTS: For the 195 case-control matched pairs, the mean age was 13.0 years and 47.7% were female. For breastfeeding, 88.7% of controls and 69.2% of JSpA cases were exposed to breastfeeding of any duration, respectively (P < 0.001). In the multivariable model, exclusive breastfeeding > 6 months was independently and significantly associated with a lower chance of JSpA development (odds ratio 0.47, 95% CI 0.30-0.72; P < 0.001). The median JSpADA6 was not significantly associated with breastfeeding for > 6 months. However, vaginal delivery was significantly associated with a lower JSpADA6 (B = -0.65, 95% CI -1.13 to -0.17; P = 0.008).
CONCLUSIONS: This study suggests that infant factors that affect the microbiome may be associated with the occurrence and disease activity of JSpA at presentation.

BACKGROUND: Rheumatic patients have a higher frequency of tuberculosis(TB) than the general population. This study aimed to describe children and adolescents with TB and rheumatic diseases(RD) who were being treated in a reference center.
METHODS: A series of TB cases were investigated in a reference center for childhood TB in Rio de Janeiro, Brazil, from 1995 to 2022.
RESULTS: Fifteen patients with underlying RD and TB were included with 8(53%) being female. The mean age at RD diagnosis was 7.10years (SD ± 0,57 years), and the mean age at TB diagnosis was 9.81 years(SD ± 0.88 years). A total of 9 cases of pulmonary TB(PTB) and 6 cases of extrapulmonary TB-pleural(2), joint/osteoarticular(1), cutaneous(1), ocular(1), and peritoneal(1)- were described. The RD observed in the 15 patients included juvenile idiopathic arthritis(9), juvenile systemic lupus erythematosus(3), juvenile dermatomyositis(1), polyarteritis nodosa(1), and pyoderma gangrenosum(1). Among the immunosuppressants/immunobiologics, methotrexate(8) was the most commonly used, followed by corticosteroids(6), etanercept(2), mycophenolate mofetil(1), cyclosporine A(1), adalimumab(1), and tocilizumab(1). The most common symptoms were fever and weight loss, and a predominance of PTB cases was noted. GeneXpert MTB/RIF® was performed in six patients and was detectable in two without rifampicin resistance; Xpert Ultra® was performed in five patients, and traces with indeterminate rifampicin resistance were detected in three. One female patient discontinued treatment, and another passed away.
CONCLUSIONS: The case series demonstrated the importance of suspecting and investigating TB in RD affected patients who are using immunosuppressants/ immunobiologics, particularly in countries with high rates of TB such as Brazil.