Medical College of Wisconsin
CTSICores SearchResearch InformaticsREDCap

Impact of the Season of Birth on the Development of Juvenile Idiopathic Arthritis in the United States: A Nationwide Registry-based Study. J Rheumatol 2021 12;48(12):1856-1862



Pubmed ID




Scopus ID



OBJECTIVE: Autoimmune disorders result from the interplay of genetic and environmental factors. Many autoimmune disorders are associated with specific seasons of birth, implicating a role for environmental determinants in their etiopathology. We investigated if there is an association between the season of birth and the development of juvenile idiopathic arthritis (JIA).

METHODS: Birth data from 10,913 children with JIA enrolled at 62 Childhood Arthritis and Rheumatology Research Alliance Registry sites was compared with 109,066,226 US births from the same period using a chi-square goodness-of-fit test. Season of birth of the JIA cohort was compared to the US population estimate using a 2-sided 1-sample test for a binomial proportion and corrected for multiple comparisons. Secondary analysis was performed for JIA categories, age of onset, and month of birth.

RESULTS: A greater proportion of children with JIA were born in winter (January-March) compared to the US general population (25.72% vs 24.08%; corrected P < 0.0001). This observation was also true after stratifying for age of onset (a?? or > 6 yrs). When analyzed by the month of birth, a greater proportion of children with JIA were born in January compared to the US population (9.44% vs 8.13%; corrected P < 0.0001).

CONCLUSION: Relative to the general population, children with JIA are more often born in the winter, and specifically in the month of January. These observations support the hypothesis that seasonal variations in exposures during the gestational and/or early postnatal periods may contribute to development of JIA.

Author List

Dave I, Estroff B, Gergely T, Rostad CA, Ponder LA, McCracken C, Prahalad S, CARRA Registry Investigators


James J. Nocton MD Professor in the Pediatrics department at Medical College of Wisconsin
James Verbsky MD, PhD Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Arthritis, Juvenile
Cohort Studies
United States