Objective: We investigated whether long-term, low-level exposures to solvents had adverse longitudinal effects on pulmonary functions.
Methods: The study was performed on 1091 workers 5 years ago and then on 697 workers 5 years later. Chronic respiratory symptoms were recorded using a questionnaire on respiratory symptoms.
Results: The annual decrease in forced expiratory volume in 1 second in the workers exposed to solvents was not significantly different from that of the unexposed workers (69.7 ± 89.9 vs 75.8 ± 87.6 mL/yr, P = 0.5, respectively). In 453 workers who were exposed to solvents 5 years ago, the prevalence rate of asthma was 1.1%. Five years later, it was 3.6% in 193 workers from the same group. The difference was statistically significant (P = 0.03).
Conclusions: Longitudinally, the chronic exposure to low doses of solvents does not adversely affect the pulmonary functions, whereas it increases the asthma prevalence.