Epidemiologic studies suggest that environmental factors may be part of the yet unknown causation of multiple sclerosis (MS). Several case-control studies have shown a history of elevated exposure to organic solvents among cases.
Three cohorts of 11,542 painters, 36,899 construction workers and 9,314 food-processing workers were identified by the 1970 census in Norway. The cohorts were followed until the end of 1986 for registration of disability pensions.
A total of nine painters, 12 construction workers and six food workers had received a disability pension because of MS. The relative risk for painters compared with workers not exposed to organic solvents was 2.0 (95% confidence inter-val = 0.9-4.5) for MS.
These results are compatible with the hypothesis of organic solvents being a possible risk factor for MS.