Environmental Rheumatology
Comparison of pre- and post-natal environmental exposures in United States versus Brazilian patients with juvenile dermatomyositis
T.M. Arabi1, S.C. Farhat2, C.C. Valoes3, S. Shenoi4, S. Kim5, B.O. Carneiro6, L.G. Rider7, A.M. Elias8
- Children’s Institute, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil. tamimaarabi89@gmail.com
- Children’s Institute, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
- Hospital da Criança de Maceió e Hospital Universitário Professor Alberto Antunes, Maceió, Brazil.
- Seattle Children’s Hospital and Research Center, University of Washington, Seattle, WA, USA.
- University of California, San Francisco, CA, USA.
- Children’s Institute, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
- Environmental Autoimmunity Group, Clinical Research Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Bethesda, MD, USA.
- Children’s Institute, Hospital das Clínicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil.
CER19352
Environmental Rheumatology
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PMID: 41562348 [PubMed]
Received: 26/09/2025
Accepted : 08/01/2026
In Press: 19/01/2026
Abstract
OBJECTIVES:
The objective of this study is to assess the differences in environmental exposures of juvenile dermatomyositis (JDM) patients in Brazil versus United States (U.S.).
METHODS:
JDM patients from 4 centres [3 U.S. (n=66), 1 Brazil (n=36)] were enrolled. Exposures during pregnancy were assessed by questionnaire, including occupational exposures, sources of inhalable pollution near the mother’s home and work, and exposure to tobacco/alcohol.
RESULTS:
JDM mean age onset was 7.12 (SD±4.02) years for U.S. patients and 5.30 (SD±2.52) for Brazilians (p=0.004). During pregnancy, American mothers more frequently worked outside home than Brazilians (65.2% vs. 41.2%; p=0.032). Americans more often worked in offices (51.2% vs. 14.3%; p=0.027) and Brazilians, as teachers (28.6% vs. 4.8%; p=0.029). Americans commuted to work more frequently by subway (68.3% vs. 7.1%; p=<0.01), Brazilians, by bus (64.3% vs. 14.6%; p=0.001). Brazilians were more frequently exposed to dust (42.9% vs. 9.5%; p=0.01) and tobacco (50% vs. 23.1%; p=0.01). Places where Brazilians worked (35.7% vs. 9.1%; p=0.03) and lived (50% vs. 10.6%; p=<0.01) during pregnancy were closer to factories and quarries, as well as where the child was born (32.3% vs. 8.6%; p=0.007). After birth, Brazilian patients were more frequently exposed to tobacco, both through their fathers’ smoking (26.5% vs. 6.2%; p=0.009) and other household residents (36.4% vs. 9.2%; p=0.002).
CONCLUSIONS:
Earlier onset of symptoms, possibly related to early life environmental exposures, was observed in Brazilian patients. Their mothers lived and worked closer to factories and quarries, commuted to work by bus and were more exposed to dust and tobacco.
