Researchers in Sweden report that long-term, repetitive manual work is associated with an increased risk for rheumatoid arthritis (RA). Their study, discussed at the recent European League Against Rheumatism Annual Congress (EULAR 2016) in London, is the first to show a link between work-related physical activity and RA.
The team, from the Institute of Environmental Medicine, Karolinska Institute in Stockholm, analyzed information from 3,680 RA patients and 5,935 matched individuals taking part in the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA), a study investigating possible RA risk factors, including both genetic and environmental ones.
To assess predisposition, the researchers compared the risk of developing RA in individuals with and without the HLA-DRB1 genotype, which is known to be associated with an increased incidence of the disease. They performed the analysis considering the absence/presence of ACPA (anti-citrullinated protein antibodies) among patients with RA. ACPA are antibodies directed against an individual’s own proteins (autoantibodies) that target the citrullinated peptides and proteins present in most RA patients.
“We found that some types of physical workload increased the odds of developing RA more than others,” Pingling Zeng with the Institute of Environmental Medicine, said in a recent news release. “There also appeared to be a significant interaction between genetic makeup, in terms of HLA-DRB1 genes, and the risk of ACPA-positive RA from specific types of physical workload.”
Results revealed that the odds ratio of developing RA in exposed versus unexposed individuals was equal or greater than 1.5, with several repetitive types of manual work, like exposure to repeated vibration (1.5), moving or lifting objects weighing more than 10 kilograms (1.5), turning and bending (1.6), and working with hands below the knee level (1.7) or above shoulder level (1.8), leaving people at higher risk of developing the inflammatory disorder.
“These new insights into the cause of RA may hopefully lead to effective strategies to prevent the development of RA, particularly in those RA patients with a susceptible genotype,” Zeng concluded.