Long-term Health Experience of Jet Engine Manufacturing Workers: II. Total and Cause-Specific Mortality Excluding Central Nervous System Neoplasms

Abstract

As part of an exploratory investigation of an unusual occurrence of glioblastoma at one jet engine manufacturing facility located in North Haven, Connecticut (CT), we examined total and cause-specific (excluding central nervous system neoplasms) mortality rates at eight of the company's CT facilities. Subjects were 223,894 workers ever employed in one or more of the manufacturing facilities from 1952 to 2001. Vital status was determined through 2004 for 99% of subjects and cause of death for 95% of 68,701 deaths. We computed standardized mortality ratios (SMRs) based on US and CT state rates and modeled internal cohort rates. We observed overall deficits in deaths based on national and state comparisons from all causes, all cancers and most of the cause of death categories examined. State comparisons revealed statistically significant excesses in deaths greater than 25% for kidney cancer (68 deaths, SMR = 1.30, CI = 1.01-1.65) and "other non-malignant respiratory disease" (291 deaths, SMR = 1.27, CI = 1.13-1.42) among subjects employed only at North Haven, and for bronchitis (713 deaths, SMR = 1.28, CI = 1.18-1.37) among all hourly workers. These excesses occurred mainly among short-term workers and hourly workers. We found no evidence of elevated mortality risks for all causes combined, all cancers combined and most of the causes of death categories examined. The pattern of findings for kidney cancer, bronchitis and other non-malignant respiratory disease, based on currently available data, suggests these excesses may be due to non-occupational risk factors or to external occupational factors. We will investigate these excesses further when detailed work history and exposure data from the companion exposure assessment project become available.