Association of Short‐Term Ultraviolet Radiation Exposure and Disease Severity in Juvenile Dermatomyositis: Results From the Childhood Arthritis and Rheumatology Research Alliance Legacy Registry

Abstract

Objective. Ultraviolet (UV) radiation is considered to be an important environmental factor in the clinical course of children with juvenile dermatomyositis (DM). We aimed to evaluate the association between UV radiation and severe disease outcomes in juvenile DM.Methods. This is a cross-sectional study of patients with juvenile DM enrolled in the US multicenter Childhood Arthritis and Rheumatology Research Alliance (CARRA) Legacy Registry from 2010 to 2015. The mean UV index (UVI) in the calendar month prior to symptom onset in each subject's zip code was calculated from daily satellite solar noon measurements. Multivariable logistic regression was used to model the relationship between the mean UVI and calcinosis as well as other outcomes of severe disease. Covariates included sex, race, age, time to diagnosis, disease duration, and latitude.Results. In a multivariable model, there was no association between the mean UVI and calcinosis. African American race was associated with a 3-fold greater odds of calcinosis. However, there was a significant statistical interaction between race and mean UVI. Accounting for this interaction, the odds of calcinosis markedly decreased in African American subjects and steadi ly increased in non-African American subjects over a range of increasing the mean UVI. Higher mean UVI was associated with decreased odds of using biologics or nonmethotrexate disease-modifying antirheumatic drugs and skin ulceration.Conclusion. We described a novel association between UV radiation, calcinosis, and race in a large cohort of patients with juvenile DM. This study furthers our knowledge of the role of UV radiation in the clinical course of juvenile DM and highlights the complex interplay between genes and environment in the clinical phenotypes and development of calcinosis in children with juvenile DM.

The influence of environmental factors related to Juvenile Dermatomyositis (JDM), its course and refractoriness to treatment.

“…And similar than the 60% found by Stringer et al in 2008 in a Canadian cohort of patients [20]. Median age at JDM onset in our study was compatible with the median of 5 years found in the cohort studied by Neely et al in 2019 with patients from the CARRA registry (Childhood Arthritis and Rheumatology Research Alliance) [7].…”

“…Environmental factors act as a trigger on the immune system of genetically susceptible people and may cause the onset of JDM. Some triggers associated with the development of in ammatory myopathies have already been described, such as infections [5,6], direct exposure to ultraviolet rays and maternal exposure to inhalable elements [3,7,8].…”

Juvenile Dermatomyositis: New Clues to Diagnosis and Therapy

“…A variety of physical conditions may contribute to the development of JDM, including exposure to ultraviolet light [26]; the genetics of the patient appears to be associated with susceptibility to the increased dosage of UVB at equator-related latitudes [27]. Higher mean UV index exposure was associated with increased odds of using biologics or non-methotrexate disease-modifying antirheumatic drugs and skin ulceration, as well as developing calcinosis [28]. Increasing particulate pollution in the city atmosphere inflicts damage to the developing fetus and later in life [29].…”

Relationship of ultraviolet light exposure and cutaneous and systemic disease activity in youth with childhood-onset systemic lupus: Results from the Childhood Arthritis and Rheumatology Research Alliance Registry

“…However, the odds of calcinosis markedly decreased in African American participants and steadily increased in non-African American participants over the range of increasing mean UVI [24]. The seasonal rates of are in other autoimmune disease have also been described, especially multiple sclerosis, psoriasis, rheumatoid arthritis [25].…”