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Data File: MFFEGWA1

Data Files (2):
Study Name: Mortality Study Among Female Nuclear Weapons Workers at Los Alamos National Laboratory, Zia Company, Rocky Flats, Hanford, Mound, Savannah River, Oak Ridge X-10, Y-12 and K-25, Fernald, Linde and Pantex
Cohort Size: 65,984
Races: Black, White
Sexes: Female
Diseases: Cancer and Non-Cancer Mortality
Earliest Exposure: 01/01/1943
Latest Exposure: 12/31/1979
Follow-Up: 12/31/1994
Exposure Type: External penetrating radiation
Exposure Agent: No data available.
Covariate: Facility, Hire Date
Sites: Fernald Site, Hanford Site, Linde Plant, Los Alamos National Laboratory, Mound Plant, Oak Ridge K-25 (Gaseous Diffusion Plant), Oak Ridge X-10 (Oak Ridge National Laboratory), Oak Ridge Y-12, Pantex Plant, Rocky Flats Plant, Savannah River Site, Zia Company
This data file set comprises two analytic data files used in a retrospective cohort mortality study of female workers at one or more DOE facilities by Gregg Wilkinson. The sites include Los Alamos National Laboratory; Zia Company; Rocky Flats; Hanford; Mound; Savannah River; Oak Ridge X-10, Y-12, and K-25; Fernald; Linde; and Pantex. The year 1994 is the end of the study date or end of follow-up.
Although women have been employed in the nuclear weapons industry since its inception, little is known about the potential health effects that women may experience as a result of work-related exposures to ionizing radiation and non-radiation hazards. Studies that have reported results for women have tended to suffer from small numbers of observations, short follow-up, young average age of cohort members, and a lack of exposure information. Despite these shortcomings, suggestive but inconsistent elevations for several types of neoplasms have been reported including several known to be associated with ionizing radiation and for several non-neoplastic conditions. This study attempted to overcome the shortcomings just mentioned by combining cohorts of female nuclear workers from 12 U.S. nuclear weapons facilities. These included Los Alamos National Laboratory; Zia Company; Rocky Flats; Hanford; Mound; Savannah River; Oak Ridge X-10, Y-12, and K-25; Fernald; Linde; and Pantex.
The specific aims of this study were to combine data for female employees from these 12 facilities, to estimate doses or exposures to individuals for radiation and nonradiation hazards, to estimate the relative risk of mortality from neoplastic and nonneoplastic diseases, and to estimate the amount of uncertainty associated with these relative risk estimates.
To accomplish these specific aims, a retrospective cohort mortality study of neoplastic and non-neoplastic health endpoints was conducted of female workers who were hired at the above facilities before 1980. The cohorts were assembled from roster files that had been developed by previously funded Department of Energy researchers at Pacific Northwest Laboratories (Hanford), ORISE (Fernald, Linde, K-25, Savannah River, X-10, Y-12) and Los Alamos National Laboratory (Los Alamos, Mound, Pantex, Rocky Flats, Zia).
Data on radiation exposures for workers at Fernald, K-25, Y-12, X-10, and Savannah River were obtained from researchers at ORISE. Data for Fernald workers were updated by information obtained directly from Fernald. No data on radiation exposures were available for Linde workers. Radiation exposure data for Hanford workers were abstracted from a file that was compiled for a study conducted by the IARC. Data on radiation exposures for Pantex, Los Alamos, and Zia workers were obtained directly from health physicists at these facilities. Updated information on radiation exposures was not available for Mound workers. Radiation exposure data for Rocky Flats workers was made available to us from researchers at the University of Colorado.
In collaboration with researchers at the University of North Carolina, we developed questionnaires on radiation dosimetry practices and data resources and on physicochemical exposures, industrial hygiene practices, and data resources. The radiation dosimetry questionnaire expanded on a questionnaire that had been previously devised by staff at the Department of Energy. These questionnaires were sent to designated contacts at the study facilities. Unfortunately, fewer than half of the questionnaires were completed and returned.
Vital status ascertainment for the combined study cohort was completed by matching a roster of study subjects, who had not already been identified as deceased, with Social Security Administration Master Death Tapes. The matching process was conducted by the Epidemiology Research Institute in Boston using a matching algorithm they developed. Death certificates were requested from state departments of health and vital statistics for individuals who were identified as deceased. Deaths were then coded to the 8th revision of the International Classification of Diseases by a qualified nosologist. Vital status follow-up ended in 1994.
A total of 65,984 women and 2,544,433.51 person-years were identified from the 12 study facilities. Among these, 13,671 deaths were observed. Although the total number of African American women varied between the study facilities, overall, less than 10 percent were identified as African American. For the total combined cohort, 32.5% had a radiation record indicating they had been monitored for external radiation. Among women with a radiation record, mean cumulative external radiation doses ranged from 0.065 cSv at Fernald to 0.966 cSv at Savannah River.
When mortality for the combined cohort was compared with U.S. death rates, fewer deaths than expected were observed for most causes of death. Exceptions were deaths from mental disorders, certain genitourinary system diseases, as well as symptoms and ill-defined conditions. Mortality from conditions that have in the past been found to be associated with exposures to ionizing radiation was not higher than expected or was close to expectation.
A strong healthy worker effect was observed for the entire cohort and for each individual subcohort with the exception of Linde, in which case the observed number of deaths was similar to the number expected. The weaker healthy worker effect observed among Linde workers was largely due to more deaths than expected from ischemic heart disease. The healthy worker effect was also observed among workers who were monitored for external radiation exposures and among workers who were not monitored for external radiation exposures.
Failure time analyses employing proportional hazards modeling were conducted to assess whether survival differs among workers at different facilities and to assess whether cumulative exposures to external penetrating radiation exposures are associated with mortality. The healthy worker effect is also observed in these analyses.
When time-dependent proportional hazards analyses of cumulative penetrating doses for all monitored employees, regardless of length of employment, were performed for all facilities combined, the relative risk of death per rem increased with increasing cumulative penetrating dose for all leukemias combined (Eighth Revision of the International Classification of Diseases [ICD8]: 204.0-207.9) other than chronic lymphatic leukemia (ICD8: 204.1). This increase was almost totally due to leukemia among X-10 workers. Relative risk estimates per rem were suggestively elevated for all cancers combined, breast cancer, and for all hematologic cancers combined (ICD8: 200.0-209).
The MFFEGWA1_d2 file is used for the radiation dose response analyses. File MFFEGWA1_d2 comprises 65,984 records, each representing one female. The records in the MFFEGWA1_d2 file pertain to a subset of the entire cohort. It contains only those individuals who were monitored for radiation exposure. Two facilities for which no updated radiation data were available are not included in this file. Individuals from the other facilities for whom there was no evidence they had been monitored for external radiation are also excluded from this file. The year 1994 is the end of the study date or end of follow-up.
File MFFEGWA1_d1 is a roster file used for SMR analyses. Each record represents one female, some of which were not used in the analysis file MFFEGWA1_d2.

Citations Associated:
Acquavella, J. F., Anaya, L., Wilkinson, G. S. (n.d.). Telephone interviewer instructions follow-up health study of nuclear workers. Los Alamos National Laboratory.
Baillargeon, J., & Wilkinson, G. S. (1999). Characteristics of the healthy survivor effect among male and female Hanford workers. American Journal of Industrial Medicine.<343::AID-AJIM4>3.0.CO;2-4
Baillargeon, J., Wilkinson, G., Rudkin, L., Baillargeon, G., & Ray, L. (1998). Characteristics of the healthy worker effect: A comparison of male and female occupational cohorts. Journal of Occupational and Environmental Medicine.
Massoudi, B.L. (1996). Adverse reproductive outcomes among females employed at Department of Energy facilities: the feasibility of epidemiologic studies. National Institute for Occupational Safety and Health (NIOSH), Health-related Energy Resarch Branch (HERB).
Wilkinson, G.S., Priore, R., Graham, R. et al. (2000). The healthy worker effect among 12 cohorts of female nuclear weapons workers. Epidemiology. 11(4):267.
Wilkinson, G.S., Trieff, N., Graham, R., Priore, R.L. (2000). Final report: study of mortality among female nuclear weapons workers. National Institute for Occupational Safety and Health.
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