The analysis sought to determine whether mortality among these workers differed significantly from the general population of females in the United States and whether the subgroup of this cohort that was exposed to radiation was at an increased risk of dying from cancer when compared to the unexposed group. The analysis focused on 6,573 white (those with race unknown were assumed to be white) females who were employed at LANL between 1943 and 1978, inclusive. Most analyses were further limited to the 5,234 white workers employed at least 6 months. The study found a standardized mortality ratio (SMR) for suicide that was significantly elevated. Rate ratios for cancers of the ovary and pancreas were also significantly elevated for radiation- monitored members of the cohort. Due to the elevated risk of suicide, an elevated rate ratio for deaths due to all causes was also observed for the radiation workers in this cohort.
The single analytic file (LAFEFILE) contains data for 6,790 females of all races employed at LANL and represents a complete roster of females hired through December 31, 1978. Some later hires are included in the file but not in the analysis. External exposure data in the file consist of dates (given in decimalized notation) on which the worker was first monitored, first received a positive exposure, first accumulated 1 rem whole- body dose, first accumulated 5 rems whole- body dose, and first received 10 rems whole-body dose. Whole-body dose was defined as the sum of all tritium, neutron, and penetrating gamma readings. External readings were available through 1981. Data pertaining to internal plutonium exposure include isotope, dates (in decimalized notation) of first and last samples, and estimated body burdens (in units of both nCi and nCi-years) of plutonium. Dates of first and last sample were through January 1, 1985. Estimated body burdens were taken through December 31, 1984; date of death; or date of the last bioassay sample. The computer code PUQFUA was used to estimate plutonium body burdens incurred by workers through 1984. Demographic data were extracted from a number of sources, including LANL personnel and medical records, and was computerized in 1982 and 1983 by the LANL Epidemiology Section.
Vital status was ascertained for 87% of the 6,790 females through December 31, 1981, the study end date. There were 430 deaths identified in this cohort.
The LANL has been a center for research in nuclear physics and weapons development since the 1940s. Sources of occupational exposures include external radiation, primarily gamma, and potential internal deposition of plutonium-238 and plutonium- 239. Pocket chambers or film dosimeters were used for personnel monitoring until 1980, when they were replaced with thermoluminescent dosimeters. Formal bioassay programs to monitor for internal exposures were begun in 1945. Results of both types of monitoring programs reflect technological improvements and changes in concepts and models.
END_STDY 12/31/1981
ENDPOINTS Mortality