Breathing in common workplace dust and fumes may increase the risk of developing severe rheumatoid arthritis, especially in combination with smoking and genetic susceptibility to the disease, suggests a new study published in The Annals of the Rheumatic Diseases.
Rheumatoid arthritis (RA) is a chronic autoimmune joint disorder affecting up to 1% of the population. The presence of so-called anti-citrullinated protein antibodies (ACPA) denotes a worse prognosis with higher rates of erosive joint damage.
Cigarette smoking is already known as a risk factor for developing RA, but the impact of breathing in workplace dust and fumes, such as vapours, gases, and solvents, remains unclear.
Increased risk of ACPA-positive rheumatoid arthritis
Researchers at Karolinska Institutet drew on data from the Swedish case-control study EIRA (Epidemiological Investigation of RA), comprising 4033 people diagnosed with RA between 1996 and 2017 and 6485 randomly selected healthy controls matched for age and sex. Personal job histories were used to estimate the exposure to 32 inhalable workplace agents. Each participant was assigned a genetic risk score based on their genetic susceptibility to developing RA.
Individuals who had been exposed to any of the occupational agents had a 25 per cent higher risk of developing ACPA-positive RA, and the risk increased with a longer duration of exposure or with more types of exposed agents. 17 out of 32 agents, including quartz, asbestos, diesel fumes, gasoline fumes, carbon monoxide, and fungicides, were strongly associated with an increased risk of developing ACPA-positive RA, but only a few agents were associated with ACPA-negative RA.
Interaction with smoking and risk genes
Individuals who were exposed to smoking as well as inhalable workplace agents, in combination with having a high genetic risk score, had an 18 times higher risk of developing ACPA-positive RA compared with those who were not exposed to any of these three factors.
“Occupational inhalable agents could act as important environmental triggers in RA development and interact with smoking and RA risk genes,” says Karolinska Institutet professor and corresponding author Lars Klareskog. “Preventive strategies aimed at reducing occupational hazards and smoking are warranted for reduction of the burden of RA, especially for those who are genetically vulnerable.”
Because it is an observational study, it cannot establish any causal relationships.
Source: Karolinska Institutet
