Exposure to occupational inhalable agents increases the risk of rheumatoid arthritis

Several previous literature evidence has recognized external exposure such as smoking as a major environmental risk factor for the development of rheumatoid arthritis (RA). Studies have also established the role of human leucocyte antigen class II shared epitope (HLA-SE) as the genetic risk factor linked to the disease. A recent study published in Annals of the Rheumatic diseases has concluded that occupational inhalable agents may serve as major environmental triggers and their conjoint exposure with smoking and RA-risk genes increase the risk for developing anticitrullinated protein antibodies (ACPA)-positive RA.

A group of Swedish researchers conducted the study by retrieving the data of occupational histories from Swedish Epidemiological Investigation of RA. The researchers investigated the exposure to 32 inhalable agents and found that exposure to any agent increased the likelihood for developing ACPA-positive RA (OR 1.25, 95% CI 1.12 to 1.38). A corresponding increase in risk was also noted with an increase in the number of exposed agents (P <0.001) or enhanced duration of exposure (P <0.001). The study has also noted elevated risk in the triple-exposed group, i.e. occupational inhalable agents, smoking and high Genetic Risk Score (GRS) compared to those without any exposure (OR 18.22, 95% CI 11.77 to 28.19).

A nationwide registry case–control study done by Wrangel et al. in 2021 has reported that occupational silica dust exposure in men was linked to a statistically significant odds ratio for seropositive (OR 1.22, 95% CI 1.05 to 1.40) and seronegative (OR 1.23, 95% CI 1.04 to 1.46) RA. Inhaled silica dust has been linked to an increased incidence of silicosis, sarcoidosis, chronic obstructive pulmonary disease, lung cancer, and chronic kidney disease. The chemical agent has been currently classified as a carcinogen by the International Agency for Research on Cancer (IARC).

The present study highlights the need to develop preventive strategies and institutional protocols aimed at minimizing occupational exposure and smoking, especially in genetically vulnerable populations.


  1. Tang B, Liu Q, Ilar A, et alOccupational inhalable agents constitute major risk factors for rheumatoid arthritis, particularly in the context of genetic predisposition and smokingAnnals of the Rheumatic Diseases Published Online First: 06 December 2022.
  2. Wrangel, Oscar MSc; Graff, Pål PhD; Bryngelsson, Ing-Liss BSc; Fornander, Louise PhD; Wiebert, Pernilla PhD; Vihlborg, Per MD. Silica Dust Exposure Increases Risk for Rheumatoid Arthritis: A Swedish National Registry Case–Control Study. Journal of Occupational and Environmental Medicine 63(11):p 951-955, November 2021.