A prospective cohort study of the chronic effects of solvent exposure

The issue of the health effects of long-term exposure to solvents still attracts considerable debate, particularly among regulators and policymakers. This is especially true for studies of neurobehavioral effects. A major reason for this debate is that cross-sectional research designs are almost universally used in this area. Cross-sectional studies suffer from problems of possible confounding by a range of unknown factors and also usually from poor estimates of exposure. This study is an attempt to solve this problem by using an inception cohort design in which the subjects are measured at the beginning of their exposure and then at intervals while their exposure continues. Two hundred first-year apprentice vehicle spray painters were entered into the study within 6 months of beginning their apprenticeship together with a comparison group of 76 first-year apprentice electricians and 49 first-year apprentice metal fabricators. Measures of neurobehavioral function using a test battery based on an information-processing model were made at study entry and will be made annually. In addition apprentice's assessments of their own exposure are being made annually and compared with workplace-exposure assessments. So far measures have been made at the beginning of the second year for the entire cohort and at the beginning of the third year for one-third of the cohort. This paper is a description of the results for this one-third. The results suggest that there were no significant changes in neurobehavioral function in the first 2 years of exposure to solvents. However, the results of workplace monitoring suggest that exposure is considerably below current exposure standards for solvents during this time.