Results from a recent study suggest that working in certain occupations may increase a worker’s risk for rheumatoid arthritis (RA), even after adjustment for lifestyle-related factors, including smoking, alcohol use, education level, and obesity (Ilar A, et al. Arthritis Care Res (Hoboken). 2017 Aug 10. Epub ahead of print).
To evaluate whether certain occupational hazards and exposures may contribute to the risk for anticitrullinated protein antibody (ACPA)-positive or ACPA-negative RA, Anna Ilar, MSc, Cardiovascular Epidemiology Unit, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, and colleagues, analyzed data from 3522 patients with the disease and 5580 controls from the Swedish Epidemiological Investigation of RA study between May 1996 and September 2014.
“Most previous studies on the associations between occupations and the risk of developing RA have not taken environmental and lifestyle risk factors into account,” Ms Ilar and colleagues explained.
Participant information was gathered on factors such as heredity, demography, socioeconomic status, occupation history, lifestyle, and psychosocial issues by way of a comprehensive questionnaire. In addition, patients and individuals in the control group were required to give blood samples to determine their ACPA status.
“There is increasing evidence suggesting that ACPA+ RA and ACPA- RA are two different subtypes of the disease with partly different etiologies,” the investigators noted.
After adjusting for smoking, alcohol use, education, and body mass index, Ms Ilar and colleagues found that, of 76 occupational groups primarily associated with exposure to noxious airborne agents, 4 jobs (3 among men and 1 among women) were linked to the onset of ACPA-positive or ACPA-negative RA.
Among men, electrical and electronics workers (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.1-3.8), bricklayers and concrete workers (OR, 2.9; 95% CI, 1.4-5.7), and material handling operators (OR, 2.4; 95% CI, 1.3-4.4) had an increased risk for ACPA-positive RA. Only workers in occupations related to manufacturing were linked to ACPA-negative RA—namely, electrical and electronics workers (OR, 2.6; 95% CI, 1.3-5.0) and bricklayers and concrete workers (OR, 2.4; 95% CI, 1.0-5.7).
Among women, the only occupational group associated with a significant risk for ACPA-positive RA was one that encompassed assistant nurses and attendants (OR, 1.3; 95% CI, 1.1-1.6). Although Ms Ilar and colleagues could not explain this correlation on a molecular level, they suggested that the physical nature of these jobs may have been a factor.
Interestingly, there was no increased risk for ACPA-positive RA in nurses (OR, 0.9; 95% CI, 0.6-1.2). Furthermore, no occupation among women was significantly linked to ACPA-negative RA.
According to Ms Ilar and colleagues, these results further confirm evidence pointing to the association between airborne noxious agents (eg, silica, asbestos, organic solvents) and the risk for RA in individuals who work in occupations that expose them to these agents.
“Our findings warrant an appreciation of occupational status in diagnostics and in estimations of risk for RA in clinical practice, as well as further efforts to understand how environment can trigger RA in order to enable future prevention of this disease,” they concluded.