Epidemiological study on workers exposed to low dimethylformamide concentrations.
Reviewing medical and epidemiological reports, no definite clinical picture could be expected as a result of a low DMF exposure and experimental research on long term toxicity has always demonstrated some adverse effects but has not been sufficient to define a no-effect level in animals. This study was designed to assess the specificity of symptoms and the relevance of adverse effects as consequence of an exposure to airborne DMF concentration in the range of the present TLV (30 mg/m3 - 10 ppm). For this purpose 100 DMF-exposed workers, with homogeneous characteristics, were compared with 100 matched controls. Both groups were selected by a careful pair-matching. Mean DMF exposure was 22 mg/m3 (range 8-58 mg/m3). Exposed subjects and their matched controls were evaluated clinically and a questionnaire was used for the registration and the comparison of subjective complaints. A laboratory assessment was performed, including transaminase and gamma-glutamyl transpeptidase. Statistical analysis was based on McNemar Test procedure. The problem of dietary alcohol intake was particularly investigated. Among symptoms studied, headache, dyspepsia and digestive impairment of hepatic type could be specifically associated with chronic DMF exposure and increased levels of gamma-GT demonstrated minimal hepato-cellular damage, even without ethanol dietary intake. No chronic sickness was diagnosed and the disturbances observed are better considered as indicators of malaise and discomfort due to a toxic effect of DMF, whose consequences are discussed.