The prevalence of rheumatoid arthritis in occupational groups.

Distributed on 66 large occupational groups the prevalence of classical, definite, probable and possible RA (according to ARA criteria) was determined in the general population. A total of 39, 418 persons were investigated in a sample survey of five geographical areas in Sweden-this being the total populations over the age of seven. The distance between the different areas is 150-650 km. Occupational groups with high prevalence of RA were: Males: Food and dairy workers, butchers, fishermen, agricultural workers, building foremen, machine and engine repairers, bakers, foremen, washers and ironers, textile workers, industry and factory workers. Females: Cleaning workers, doctors and nurses, nurse assistants, textile workers, shop assistants, bank, post and telegraph personnel and wives. From the present series it seems as if outdoor occupations with relatively heavy work have the highest prevalence of RA. Environmental factors apparently account for differences in prevalences of RA.