An apparent epidemic cluster of toxic liver disease was reexamined among workers exposed to the solvent dimethylformamide. A demographically similar but unexposed group from a preemployment population was used for comparison. Analysis, after data transformation of the liver transaminases, revealed significant differences between the two populations with respect to the serum glutamic pyruvic transaminase and the ratio of serum glutaminic oxaloacetic transaminase to serum glutamic pyruvic transaminase. Thus a value of the ratio of serum glutamic oxaloacetic transaminase to serum glutamic pyruvic transaminase. Thus a value of the ratio less than 1 may be suggestive of toxic liver disease. Medical surveillance of the working population for 14 months revealed no further cases of toxic liver disease. Dimethylformamide was almost certainly the causative agent of the original epidemic. The use of preemployment populations as a source of unexposed subjects in the analysis of occupational clusters is recommended, especially in the scenario of relatively acute, and highly prevalent, occupational diseases.
Fleming LE, Shalat SL, Redlich CA. Liver injury in workers exposed to dimethylformamide. Scand J Work Environ Health 1990; 16:289-292. doi:10.5271/sjweh.1782