ABSTRACT
BACKGROUND: Occupational studies typically observe a 20% deficit in overall mortality, broadly characterized as the healthy worker effect (HWE). Components of the HWE may be addressed by various analytical approaches. AIMS: To explore the HWE in a modern industrial cohort. METHODS: Standardized mortality ratios (SMRs) were calculated for 114,683 US chemical industry employees, who worked at least 3 days between 1960 and 2005. RESULTS: SMRs were 79 (95% confidence interval 78-80) for all causes, 81 (95% confidence interval 79-82) for heart disease, 70 (95% confidence interval 67-73) for non-malignant respiratory disease, 83 (95% confidence interval 81-85) for smoking-related cancers (buccal, cervix, oesophagus, stomach, pancreas, lung, larynx, bladder and kidney) combined and 97 (95% confidence interval 95-100) for other cancers. CONCLUSIONS: The low SMRs observed in this study are likely due to differential smoking between the cohort and the background population. Future considerations to control for the HWE should take this into account.
Subject(s)
Chemical Industry/statistics & numerical data , Neoplasms/mortality , Occupational Diseases/mortality , Bias , Cause of Death , Confidence Intervals , Female , Healthy Worker Effect , Humans , Male , Smoking/epidemiology , Survivors/statistics & numerical data , United States/epidemiologyABSTRACT
To expand a cohort of chemical workers in the Kanawha Valley, we conducted a study of 33,225 workers who were employed at three locations between 1940 and 1999. We observed no increase in overall cancer mortality. Higher risk estimates were observed for lymphosarcoma and reticulosarcoma among hourly employees who worked at the Institute or South Charleston locations. This finding was limited to men hired before 1960. We observed no new cases of angiosarcoma of the liver, a cause of death previously reported in association with vinyl chloride production at the South Charleston location. Specific risk factors for lymphosarcoma and reticulosarcoma have not been identified in previous targeted studies of this population and it is unlikely that additional cause-specific research will elucidate the etiology. Updates of the entire cohort will continue and can be used as a comparison population for chemical specific studies within these three plants.
Subject(s)
Chemical Industry , Neoplasms/chemically induced , Neoplasms/mortality , Occupational Diseases/chemically induced , Occupational Diseases/mortality , Occupational Exposure/adverse effects , Adult , Aged , Carcinogens, Environmental/adverse effects , Cause of Death , Cohort Studies , Employment , Female , Follow-Up Studies , Healthy Worker Effect , Hemangiosarcoma/chemically induced , Hemangiosarcoma/mortality , Humans , Liver Neoplasms/chemically induced , Liver Neoplasms/mortality , Lymphoma, Large B-Cell, Diffuse/chemically induced , Lymphoma, Large B-Cell, Diffuse/mortality , Lymphoma, Non-Hodgkin/chemically induced , Lymphoma, Non-Hodgkin/mortality , Male , Middle Aged , Occupational Diseases/epidemiology , Risk , Risk Factors , Sex Factors , Time Factors , Vinyl Chloride/adverse effects , West VirginiaABSTRACT
A previous mortality study for Louisiana workers of The Dow Chemical Company identified greater than expected deaths due to leukemia and aleukemia and cancer of the brain and central nervous system. The current study updated the mortality experience through 1992. No new deaths due to leukemia and aleukemia and only one new death due to cancer of the brain and central nervous system were observed. No causes of death were statistically significantly elevated. The number of observed deaths was statistically significantly less than expected for a number of disease categories. Mortality rates were not shown to be higher among Louisiana chemical employees when compared to the United States, state, and regional populations.
