Dose-dependent increase in subjective symptom prevalence among toluene-exposed workers.

Abstract

With self-completion questionnaires (with 67 questions in total), the prevalence of subjective symptoms was surveyed in 193 toluene-exposed and 65 non-exposed control women mostly at the ages of 20's. They were all nondrinkers-nonsmokers and therefore confounding effects of age, sex and the two social habits could be ruled out. The prevalence of total complaints per person correlated significantly with the time-weighted average intensity of exposure to toluene for each individual as monitored by diffusive sampling. Analyses with each symptom revealed that the prevalence of 43 symptoms (64%) out of the 67 in total was significantly higher in the exposed than in the controls. The dose dependent in-crease in prevalence was observed in 25 symptoms. In contrast, there was no difference in the prevalence of 3 hemodyscrasia-related symptoms between the exposed and the controls. The prevalence of several symptoms (e.g., body weight loss, dimmed vision, dizziness, drunken feeling, headache, sore throat, and tightness in chest) had a plateau in the exposure range below 100 ppm followed by an addi-tional increase at higher concentration, possibly justifying the current occupational exposure limit of 100 ppm, while some other symptoms gave different types of dose-prevalence relationship.