Mortality of short-term workers in two international cohorts

The purpose of this study was to compare the pattern of mortality of blue-c ollar workers employed less and more than 1 year in the man-made vitreous f iber (MMVF) and the reinforced plastic industries, the latter group being e xposed to styrene. We conducted an analysis among 21,784 workers with less than 1 year of employment (short-term workers) and 19,117 workers with 1 or more years of employment (long-term workers) employed in eight European co untries. We conducted analyses based on external as well as internal compar isons. In both cohorts, the standardized mortality ratio for all causes amo ng short-term workers was approximately 40% higher, compared with that for longer-term workers. In internal comparisons, the difference was reduced to 9% in the MMVF cohort and 11% in the styrene cohort. Workers with less tha n 1 month of employment displayed and increased mortality in both cohorts a nd in most countries. The increased mortality among short-term workers was not concentrated shortly after they quit employment. In both cohorts, short -term workers had a higher mortality from external causes, while little dif ference was seen in mortality from ischemic heart disease and malignant neo plasms. Although extra-occupational factors may contribute to increase the mortality of short-term workers and, particular, of those employed for less than 1 month, the difference observed in analyses adjusted for characteris tics of employment suggested a relatively small difference in mortality fro m most causes.