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Description of key information

- Lanes et al., 1994. Mortality among synthetic fiber workers exposed to glycerol polyglycidyl ether;
- Watkins et al., 2001. An historical cohort mortality study of synthetic fiber workers potentially exposed to glycerol polyglycidyl ether.
In both studies, mortality rates in the cohort were similar to mortality rates in the U.S. population.

Additional information

Mortality was studied among 8,878 employees who worked at any time from 1965 to 1988 at a synthetic fibers plant in North Carolina that used a finishing agent containing glycerol polyglycidyl ether (Lanes et al., 1994). Some glycidyl ethers are mutagenic and tumorigenic in laboratory animals. The main route of exposure to workers was inhalation of the spray mist, although there was also skin contact. The study was initiated by the plant to measure any possible effect of exposure to glycerol polyglycidyl ether on the occurrence of cancer among employees. Expected numbers of deaths were computed in the cohort using age-, race-, and gender-specific annual mortality rates for the United States (U.S.) population and the local county population. Since the national rates and local rates were similar, analyses using the more stable U.S. rates were used. Cohort members contributed person-time to the analysis from the date of hire until either the date of death or December 31, 1988.Then standardized mortality ratios (SMRs) were computed as the ratio of the number of observed deaths in the cohort to the number of deaths expected if employment were unrelated to mortality. Effect estimates were standardized for age, race, gender, and calendar time. The precision of the effect estimates was assessed by computing 95% confidence limits using a Poisson approximation.

There were identified 553 deaths in the cohort and the standardized mortality ratio (SMR) from all causes of death combined was 0.80. For most causes of death, mortality rates in the cohort were similar to mortality rates in the U.S. population. Among categories with at least five observed deaths, the largest effect estimate was for cancer of the central nervous system (SMR = 1.77), and the SMR for lung cancer was 0.94. The cancer categories of central nervous system (brain) and “other” lymphopoietic cancers (lymphoma and myeloma) showed weak associations with duration of employment. In case-control analyses in which work history data were utilized to compute effect estimates by duration of exposure, no increased risk of lung cancer or brain cancer among employees with more than 5 years of exposure was found. Effect estimates for lymphoma and myeloma tended to increase with duration of exposure, although there were only seven deaths in this category and the effect estimates were very imprecise. To date, this study has identified no clear carcinogenic effect of glycerol polyglycidyl ether, but plausible induction periods have not yet elapsed. The cohort should continue to be monitored to obtain more precise estimates after moderate or long induction times.

An update of the mortality experience described by Lanes et al. (1994) is reported (Watkins et al., 2001). A cohort of 8878 employees who worked between November 1, 1965, and December 31, 1988, at a synthetic fiber manufacturing facility was potentially exposed to glycerol polyglycidyl ether (T55) and was followed through December 31, 1998. The mortality experience of the race/gender groups within the cohort was strikingly similar, with both the all causes of death and all cancer causes of death below unity on both national and local standards. For white men, there were no statistically significant increases for any cause of death, with the exception of benign neoplasms. Thirty-four percent of the cohort had worked at the plant for less than 1 year. Standardized mortality ratios were compiled for those with less than 1 year of employment and for those with 1 year or more of employment. Exclusion of those cohort members who worked less than 1 year had little impact on the standardized mortality ratios.