Background Ca. 35,000 Finnish persons of working age are suffering from rheumatoid arthritis (RA). Considerable geographic variations in the age adjusted prevalence of RA were found. Occupational differences were connected with regional variation (ref.).
Objectives The aim was to detect exposures in occupations with a high risk of RA.
Methods The employed persons of 15-64 years of age receiving specially compensated medicines because of RA or other rheumatic diseases in 1971-2000 (44,190 new cases) were linked with the 5-year periodical census data for person-year calculations. The age- and region-adjusted incidence rate ratios (RR) were estimated by the generalized linear model where the administrative work was used as a reference occupation. Occupational and exposure history, and confounding factors were studied via a questionnaire sent to a sample of 5,000 rheumatic patients and 5,000 referents with hypertension (matched for sex, age, region, main occupation, and calendar period). The conditional logistic regression model was used for the comparison of exposures between the cases and referents. Smoking and familial RA were controlled for.
Results The highest age- and region-adjusted incidence rate ratios (RR; 95% CI) were observed for men in mining and quarrying work (2.1; 1.6-2.8), textile work (1.7; 1.3-2.2), iron and metalware work (1.4; 1.3-1.5), road transport work (1.3; 1.2-1.4), and for women in agricultural and horticultural work, animal husbandry (1.4; 1.3-1.5), postal work (1.3; 1.2-1.5), iron and metal ware work (1.3; 1.1-1.5), laundering and pressing work (1.3; 1.1-1.6).
The RA patients noticed cold, humidity, and draft (p<0.001) more often than their referents. Also different dusts, such as synthetic mineral fibres, concrete (p<0.01), and carbonate minerals (p<0.05) as well as chemical exposures like pesticides, paints and glues (p<0.05), vulcanization gases, and wet work (p<0.01) were reported by the RA patients more frequently. Other harmful exposures were, e.g., insects, and repetitive work.
In some occupational groups the RA patients reported several exposures significantly more often than their referents (OR; 95% CI). Such groups were: Agricultural and horticultural work and animal husbandry: humidity (3.0; 1.4-6.6), draft (2.1; 1.1-4.2), and solitary work (2.8; 1.2-6.7), Iron and metal ware work: humidity (3.3;1.4-7.8), draft (2.1; 1.1-3.8), rubbers and elastomers (8.9; 1.1-71.2), gas mixtures (2.6; 1.2-5.8), and wet work (2.4; 1.0-5.9), Postal work: humidity (2.9; 1.1-7.5), cold (2.0; 1.0-4.1), and low appreciation of the work (3.8;1.0-14.6) Textile work: humidity (7.5; 1.6-34.4), and draft (2.7; 1.1-6.4), and Chemical processing work: cold (5.7; 1.1-29.8), dirty work (10.0; 1.1-92.0).
Conclusions The results suggest that occupational exposures contributed to RA. The significant exposures were by the airways (dusts, chemicals) or by contributing factors (cold, humidity, draft).
Koskela, R-S, Martikainen, R, Klockars, M, Klaukka, T, Mutanen, P. Geographic differences in rheumatoid arthritis and work. In: Abstracts of 17th International Symposium on Epidemiology in Occupational Health; 2004; Melbourne. Occup. Environ. Health. 2004;61(11).
Disclosure of Interest None Declared