Mixed solvent exposure and organic brain damage. A study of painters.

In recent years, the possible role of occupational solvent exposure as a cause of chronic effects on the brain has been a matter of increasing concern. The present study was undertaken with the purpose of further investigating this problem, trying to minimize confounding owing to effects of recent solvent exposure and a 'healthy worker' effect. This was accomplished by studying a historical cohort of painters. The material consists of a random sample of 85 painters, and as a non-exposed control group of 85 bricklayers, selected in the same way. Parts of the study are based on this sample supplemented by a sample of 9 painters and 14 bricklayers, selected among subjects with a high degree of complaints on mental impairment. On the basis of a detailed interview on previous solvent exposure, the painters were divided into three groups with low, medium and high solvent exposure, respectively. As signs of organic brain damage we used the degree of dementia and performance in psychometric tests as assessed at a neuropsychological examination; the degree of dyscoordination as assessed from clinical neurological tests; and the degree of cerebral atrophy as assessed from CT-scans of the brain. CT-scans were performed only on a specially selected subsample. The degree of dementia, dyscoordination, and cerebral atrophy increased significantly with the degree of solvent exposure. A similar, but non-significant association was found for the relation between performance in psychometric tests and solvent exposure. The degree of dementia, of dyscoordination, and of cerebral atrophy were positively associated with each other, suggesting that they reflect different aspects of a common underlying factor, an organic brain damage. A review of the literature compared with the results of the present study suggests that a number of studies may have been biased towards negative findings owing to the inclusion in the study material of large proportions of subjects with a solvent exposure that is too little to increase the risk of an organic brain damage. Conflicting results between different studies on performance in psychometric tests may also arise from insufficient adjustment for primary intellectual level.(ABSTRACT TRUNCATED AT 400 WORDS)