Environmental factors are of importance for the etiology of rheumatoid arthritis (RA), but much remains unknown concerning the contributions from distinct occupational hazards. We explored the association between occupation and the risk of anti-citrullinated protein antibody (ACPA)+ RA or ACPA- RA.
We analyzed 3,522 cases and 5,580 controls from the Swedish population-based Epidemiological Investigation of Rheumatoid Arthritis case-control study. A questionnaire was used to obtain information on work history and lifestyle factors. Blood samples were drawn for serologic analyses. Unconditional logistic regression was used to calculate the odds ratio (OR) of RA associated with the last occupation before study inclusion. Analyses were performed with adjustments for known environmental exposures and lifestyle factors, including pack-years of cigarette smoking, alcohol use, body mass index, and education.
Among men, bricklayers and concrete workers (OR 2.9, 95% confidence interval [95% CI] 1.4-5.7), material handling operators (OR 2.4, 95% CI 1.3-4.4), and electrical and electronics workers (OR 2.1, 95% CI 1.1-3.8) had an increased risk of ACPA+ RA. For ACPA- RA, bricklayers and concrete workers (OR 2.4, 95% CI 1.0-5.7) and electrical and electronics workers (OR 2.6, 95% CI 1.3-5.0) had an increased risk. Among women, assistant nurses and attendants had a moderately increased risk of ACPA+ RA (OR 1.3, 95% CI 1.1-1.6). No occupations were significantly associated with ACPA- RA among women.
Mainly occupations related to potential noxious airborne agents were associated with an increased risk of ACPA+ or ACPA- RA, after adjustments for previously known confounders.