Increased acquired dyschromatopsia among solvent-exposed workers: an epidemiology study on 249 employees of an aluminum-foil printing factory.
OBJECTIVE: To analyze the effects on color vision of chronic exposure to mixtures of solvents including ethyl acetate, ethanol, and ketones among the workers of a large factory specializing in the manufacture of photoengraved aluminum packaging. METHODS: We analyzed a group of 129 subjects who had been exposed to solvents for more than 3 years (mean age 40 years, range 25 59 years) and a nonexposed group of 120 subjects (mean age 41 years, range 21-57 years). The two groups had a similar length of service (17 and 19 years on average, respectively). The exposed subjects consumed more tobacco and alcohol than the nonexposed workers. The study involved administration of the Lanthony D-15 desaturated test. The subjects were classified as having or not having dyschromatopsia on the basis of Lanthony's criteria and the chromatic confusion index (CCI) was calculated according to Bowman's method. After observation of the work stations and analysis of an occupational questionnaire the findings were used to construct a cumulative exposure index covering the whole of each subject's working life. Air samples were taken at each work station and in each production sector to determine current exposure. RESULTS: The average cumulative exposure index was 194 (median 174, range 27-513). The average hygienic effect index (according to ACGIH recommendations), regularly used for atmospheres containing mixtures of products, varied between 12% and 27% of the occupational limit values permitted under French legislation. As regards color vision, 23% of the exposed group had dyschromatopsia, as did 13% of the nonexposed group, with the odds ratio (OR) adjusted for age and consumption of tobacco and alcohol being 1.99 (1.02, 3.89). The analysis of the dose-response relationship according to the cumulative exposure index showed an OR of 1.59 for the lowly exposed group (index < 174) and an OR of 2.40 for the highly exposed group (index > 174) as compared with the nonexposed group. Subjects with complex color vision loss (n=23) had a significantly higher cumulative exposure index than those with blue-yellow loss (n=23; 232 versus 155; P=0.04). The CCI was on average higher in the exposed group, but the difference between the two groups was not significant. CONCLUSION: The results of this study are in favor of an increased risk for impairment of chromatic discrimination among workers exposed to mixtures of solvents including mainly ethyl acetate, ethanol, and ketones.