Exposure to animals and risk of oligoarticular juvenile idiopathic arthritis: a multicenter case-control study

Background: An inverse association between early contact with
microbial compounds and respiratory allergies is well established.
The protective effect of infant contact with animals was also shown
for inflammatory bowel disease (IBD) and systemic lupus
erythematosus (SLE). We aimed to test the association between
animal contact in infancy and oligoarticular juvenile idiopathic
arthritis (OA JIA). Methods: Parents of children with OA JIA
registered at the Hospital for Pediatric Rheumatology in
Garmisch-Partenkirchen were asked to complete a questionnaire.
Children who underwent strabismus surgery at six referral centers
for ophthalmology served as controls. Children age 6 to 18 years
born in Germany without malformations were included (238 cases;
response 89% and 832 controls; response 86%). Data were analyzed
using logistic regression models after adjusting for potential
confounders. Results: Neither place of living (urban vs. rural
area), living on a farm, nor regular farm animal (adjusted odds
ratio 0.79; 95% confidence interval 0.42-1.47) or pet contact
(0.79; 0.55-1.14) during infancy were clearly related to case
status. Allergic rhinitis was inversely related to OA JIA (0.57;
0.34-0.95). Neither place of living (urban vs. rural area), living
on a farm, nor regular farm animal (adjusted odds ratio 0.79; 95%
confidence interval 0.42-1.47) or pet contact (0.79; 0.55-1.14)
during infancy were related to case status. Allergic rhinitis was
inversely related to OA JIA (0.57; 0.34-0.95). Conclusions: Contact
with farm environments in infancy might not be associated with OA
JIA. This finding is consistent with previous findings for diabetes
mellitus type 1 but contradicts results for IBD and SLE.