Environmental Factors Associated with Clinical and Autoantibody Phenotypes in Juvenile Idiopathic Inflammatory Myopathies

Friday, November 08, 2013 — Poster Session III
10:00 a.m. – 12:00 p.m.	FAES Academic Center (Upper-Level Terrace)	NIEHS	CLIN-22

Authors

L.G. Rider
M. Shah
G. Mamyrova
L
Vegosen
L. Wu
T.P. O’Hanlon
A.V. Jansen
M.M. Rice
I.N. Targoff
F.W. Miller

Abstract

The pathogenesis of juvenile idiopathic inflammatory myopathies (JIIM) likely involves environmental exposures in genetically susceptible individuals. Using a national database, we correlated exposures within 6 months of illness onset, as well as ultraviolet radiation exposure and seasonal clustering of birthdates, with clinical and autoantibody phenotypes. Most (60%) JIIM patients had an exposure ≤ 6 months before illness onset, including infections in children who were myositis autoantibody negative or younger at diagnosis (OR 2.7–3.9) and stressful life events in older patients (OR 3.5). In girls, the odds of having JDM versus JPM increased per unit increase in their highest UV index score one month before illness onset (OR = 1.18). In white males, the average and highest UV indices were associated with increasing odds of anti-p155/140 autoantibodies (ORs 1.30 and 1.23, respectively). Across US geoclimatic regions, the average UV index was associated with increasing odds of JDM and anti-p155/140 autoantibodies. Some JIIM subgroups had seasonal birth distributions, including Hispanic JIIM patients, patient with anti-p155/140 autoantibodies, and those with the HLA risk factor allele DRB1*0301. The JIIMs may be related to multiple exposures, including infections, UV radiation, and seasonal early-life exposures, which vary among phenotypes.