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Epidemiologic studies to evaluate health effects of uranium milling.
NIOSH 2002 Aug; :1-11
This documents the completion of data collection by the University of New Mexico under the Cooperative Agreement U60 614568 "The Health Effects of Uranium Milling". The overall goals of this research effort are to test whether chronic respiratory and renal effects are associated with exposures to silica and uranium dusts in former uranium mill workers. These objectives are congruent with the directives of the United States Congress provided in Public Law 103-139 for a "study of the health effects of uranium milling, including the effects of exposure to radon, chemicals and uranium, on the health of those individuals employed in uranium mills in the southwestern United States during the period beginning on January 1, 1947 and ending on December 31, 1971." The current health status of former uranium mill workers was investigated using a cross-sectional design. Employment records of uranium mill companies were used to establish a sampling frame for the recruitment of a sample of persons who worked in mills for at least one year in job titles associated with uranium processing, and who worked less than three months in underground uranium mines. Reference subjects of comparable ages and ethnic backgrounds who never worked in uranium mills (and less than three months in mines) were recruited from a pool of friend referrals provided by the former uranium mill workers. Clinical tests and interviews were conducted in a mobile testing van during August 1999 through March 2000, in Grand Junction, Colorado, Moab, Utah, and Grants and Albuquerque, New Mexico. Testing was conducted in a mobile van equipped to perform chest x-rays, spirometry, phlebotomy, and urine collection. Detailed work histories and health information were collected in standardized interviews with each subject. A total of 256 former uranium mill workers and 39 reference subjects were tested and interviewed. The research protocol and data collection instruments were reviewed and approved by the institutional review boards of NIOSH, the University of New Mexico Health Sciences Center, and the Navajo Nation. Informed consent was obtained from each research subject prior to clinical testing and interview. Following data collection, clinical and laboratory chemistry analyses were conducted. Chest x-rays have been read independently by three NIOSH-certified B-readers, who followed International Labor Office guidelines to score the posterior-anterior films for the presence of opacities and profusion. Similarly spirometry tracings of the forced expiratory flow maneuvers were analyzed in accordance with American Thoracic Society guidelines, to obtain measures of forced vital capacity (FVC), forced expiratory flow (FEV1), and forced expiratory flow (FEF25-75). Analyses of urine samples quantified levels of beta 2 microglobulin, hexosaminidase, amino acids, and creatinine. With assistance from epidemiologists and biostatisticans at NIOSH, the data have been assembled to begin statistical analyses of hypotheses to determine if respiratory and renal functions are impaired. These hypotheses are: The prevalence of cough, phlegm, wheeze, and dyspnea, corrected for cigarette smoking, are higher in former uranium mill workers than in the no mill employment reference group. The prevalence of pneumoconioses (profusion1/0 or greater on chest x-ray films) is higher in former uranium mill workers than in the no mill employment reference group. The mean percent predicted FEV1, FVC, and FEV1/FVC ratio are lower in former uranium mill workers than in the no mill employment reference group. Mean levels of beta-2-microglobulin, hexosaminidase, and amino acids in urine are higher in former uranium mill workers than in the no mill employment reference group. More specific estimates of potential exposure to silica dust and uranium will be derived. Work history data collected during the interviews will be used to calculate the total number of years of employment in uranium mills, and the number of years in specific job titles and process areas. These exposure metrics will allow consideration of the relationship of respiratory and renal status measures, and years of work in specific job titles (and areas) where exposure to silica dust and uranium were possible. Thus, our hypotheses can be restated as: The percent predicted FEV1, FVC, and FEVl/FVC are inversely related to the cumulative number of years spent in crushing and sampling operations. Levels of beta-2-microglobulin, hexosaminidase, and amino acids in urine are inversely related to the cumulative number of years spent in yellow cake drying and packaging operations. In a previous study (Dawson, Madsen and Spykerman 1997), former uranium mill workers have voiced serious concerns about a broader range of health problems and impacts on quality of life). To investigate the potential impact of uranium mill employment on health-related quality of life, the following hypotheses will be tested: The mean scores for quality-of-life batteries are lower in the sample of former uranium mill workers relative to the sample of reference subjects. Quality-of-life measures are correlated with reduced spirometric lung function. Quality-of-life measures are correlated with reduced renal function as reflected in urinary biomarkers. Quality-of-life indices decrease with increasing number of years of work in uranium mills.
Uranium-compounds; Epidemiology; Milling-industry; Respiratory-system-disorders; Exposure-levels; Occupational-exposure; Silica-dusts; Silicates; X-ray-analysis; Spirometry; Urinalysis; Amino-acids; Pneumoconiosis
Final Cooperative Agreement Report
NTIS Accession No.
Research Tools and Approaches: Exposure Assessment Methods
National Institute for Occupational Safety and Health
University of New Mexico, Albuquerque, New Mexico
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division