Exposure to organic solvents and multiple sclerosis.

Abstract

In recent years, a number of epidemiologic studies of MS have targeted occupational exposure. Some of these studies have considered organic solvent exposure and have indicated an association with MS. An etiologic role of organic solvents has been discussed as being important in both prevention of and compensation claims for occupational disease. Methods. Thirteen published studies of solvent exposure and MS were reviewed for best evidence synthesis,1 a technique combining the detailed analysis of critical issues and study characteristics of traditional narrative reviews with the quantification and systematic literature search methods of meta-analysis. There were nine case-control studies, one proportional mortality study, two prevalence comparisons, and one ecologic study. An overview of the studies is shown intable 1. A more detailed analysis including a meta-analysis is published elsewhere.2 View this table: Table 1 Studies of MS and solvent exposure (total cases: 1,163) Results. Our group performed the first case-control study in 1988 in Sweden.3 Population controls were used. The aim was to further investigate the possible connection between solvent exposure and MS that was found in an earlier prevalence comparison published in 19824 of workers in the shoe and leather industry in Italy (relative risk [RR] = 4.9; 95% confidence interval [CI]: 2.1-11.0). The study in Sweden found an odds ratio (OR) greater than 1 for organic solvent exposure in men, especially in combination with welding. In 1989, a co-twin study from Finland5 that investigated solvent exposure among twins with MS and their healthy twin siblings showed a negative association. In contrast, a matched case-control study from Denmark6 showed on OR of 2.0 and 95% CI of 0.8-4.7. A case-control study in France7 listed the professions of cases and controls but did not present any estimation of actual solvent exposure. No predominance of occupations …