Exposure to textile dust may be associated with an increased risk of developing rheumatoid arthritis (RA), according to research published in Annals of the Rheumatic Diseases.
Chun Lai Too, MD, PhD, from the Institute for Medical Research in Kuala Lumpur, Malaysia, and colleagues found that individuals with the human leukocyte antigen DR β-1 (HLA-DRB1) shared-epitope (SE) alleles were at increased risk for developing anti-citrullinated protein antibody (ACPA)-positive RA.
This finding, as well as the significant gene-environment interaction between HLA-DRB1 SE and textile dust, “supports the hypothesis that various lung exposures may play an important role in the etiology of RA,” the authors wrote. The researchers also found that individuals exposed to textile dust also had an increased risk for ACPA-negative RA, for which there is no link to HLA-DRB1 SE.
Previous research has linked cigarette smoking and silica exposure to an increased risk of RA. To investigate whether exposure to textile dust also increases the risk of RA, the researchers analyzed data from 910 women with early RA and 910 matched controls from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis, a population-based case-control study.
The researchers conducted face-to-face interviews to obtain information on lifestyle and environmental exposures, and obtained sera and DNA samples to perform HLA-DRB1 genotyping. Participants with 1 or 2 SE alleles were categorized as SE-positive. They observed that occupational exposure to textile dust was associated with an increased risk of both ACPA-positive and ACPA-negative RA among Malaysian women.
“We note that the association between textile dust exposure and risk for RA differs from what has previously been observed for smoking and silica, as textile dust exposure is associated with risk for both ACPA-positive and ACPA-negative disease, whereas smoking and silica provide risk for only ACPA-positive disease,” the authors wrote.
“We do not have any mechanistic hypothesis for this difference and can only speculate that textile dust exposure may have a more general effect on immune activation [and] in ACPA-negative disease than is the case for cigarette smoke and silica dust exposure.”
The researchers noted that they could not test whether there was an interaction between textile dust and smoking with regard to the risk of developing ACPA-positive RA because almost all of the women in the study had never smoked.
The finding that textile dust increased the risk of both ACPA-positive and ACPA-negative RA indicates that other mechanisms may be involved that require further investigation.
However, “[from] a public health perspective, [these] results imply that efforts should be considered to reduce the incidence of RA by reducing occupational exposure to textile dust.”
Summary and Clinical Applicability
Researchers found that individuals who were occupationally exposed to textile dust and who also had HLA-DRB1 SE alleles were at high risk of developing ACPA-positive RA.Unlike with cigarette smoking or silica exposure, however, exposure to textile dust was also associated with an increased risk of ACPA-negative RA.
These results imply that efforts should be considered to reduce the incidence of RA by reducing occupational exposure to textile dust.
Too CL, Muhamad NA, Ilar A, et al. Occupational exposure to textile dust increases the risk of rheumatoid arthritis: results from a Malaysian population-based case–control study. Ann Rheum Dis. 2015; doi:10.1136/annrheumdis-2015-208278.