Occupational chronic solvent encephalopathy in Finland 1995-2007: incidence and exposure.

PURPOSE: The aim of the study was to define the incidence of chronic solvent encephalopathy (CSE) in Finland during 1995-2007, evaluate the duration and nature of exposure, and identify the work tasks where CSE is encountered. METHODS: Data were from the register and patient records at the Finnish Institute of Occupational Health. The Finnish Job-Exposure Matrix (FINJEM) and National Statistics were used to estimate the incidence of CSE in exposed workforce. RESULTS: CSE cases during 1995-2007 numbered 129. The annual incidence has decreased from 8.6 to 1.2/million employed, i.e. from 18 to 3 patients per year. The number of suspected patients has, however, remained constant (mean 38.6/year). The mean age at diagnosis was 52.8, the mean duration of exposure 28.4 years, and the mean occupational exposure limit years (OELY) 10.5. During 1995-2007, the mean age increased annually by 0.6 and years of exposure by 0.8, but OELY remained constant. In comparison to FINJEM, the highest incidence was in workers exposed to aromatic hydrocarbons. Relative to workforce in occupations with solvent exposure, CSE was most frequent in wooden surface finishers and in industrial, metal, or car painters followed by floor layers and lacquerers. CONCLUSIONS: The incidence of CSE has declined due to legislative, technical, and hygienic actions. CSE is most probable in spray painting tasks with main exposure to aromatic hydrocarbons, when occupational solvent exposure exceeds 20 years, and the age of the worker is above 45. Our results indicate slower CSE development at lower exposure levels.