Background/Purpose

Juvenile Idiopathic Arthritis (JIA) is a heterogenous group of disorders that is characterized by chronic arthritis in children without known etiology. Environmental factors that act as triggers in a genetically susceptible host are one of the current postulated etiologies of JIA. Although research that focusses on environmental risk factors in JIA is scant, to date there has been some data to suggest a role of infections, exposure to smoking and lack of breastfeeding. This case control study examines the association of selected environmental risk factors in children with JIA.

Methods

JIA cases were identified at outpatient rheumatology clinic visits over 18 months (2012 to 2013) at a major Children’s facility. Enrolled JIA cases were asked to identify three control playmates of similar age and gender without JIA. Both cases and controls completed a one time questionnaire on environmental risk factors in reference to critical time period (at JIA case symptom onset). Controls who responded were frequency-matched to cases by age and gender. Logistic regression adjusted for age and gender was used to determine associations with JIA, and odds ratios are reported with 95% confidence intervals.

Results

223 JIA cases and 86 controls submitted data that was analyzed. Baseline demographic characteristics were similar between cases and controls. Approximately 5% of mothers smoked during pregnancy among cases and controls with OR 0.8 (95% CI: 0.3 -2.4; p value 0.7). Maternal smoking at JIA onset had OR 1 (95% CI: 0.5 -2.3). The odds of JIA for other selected environmental risk factors were as follows: breastfeeding in first year of life: 1.1 (95% CI: 0.6 -2.1), hospitalization with infection in first year of life: 1.7 (95% CI: 0.5 – 5), daycare attendance <6 years of age 1.3 (95% CI: 0.8 – 2.1), household pets 1.2 (95% CI: 0.7 - 2), urban residence 0.7 (95% CI: 0.4 -1.1), stressors in family (death, divorce, move, new school, unemployment) 1 (95% CI: 0.6 -1.7). Limitations of the study include selection bias as cases were identified though outpatient rheumatology visits and overmatching that was accounted for in the analysis.

Conclusion

There was no association between maternal smoking during pregnancy or subsequent maternal smoking at JIA symptom onset, infections in first year of life, daycare attendance, household pets, urban residence or family stressors and development of JIA in this case control study.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/environmental-risk-factors-and-development-of-juvenile-idiopathic-arthritis/