Factors linked to participant attrition in a longitudinal occupational health surveillance program.

BACKGROUND: For occupational medical screening programs focused on long-term health surveillance, participant attrition is a significant barrier to success. We investigate demographic, medical history, and clinical data from National Supplemental Screening Program (NSSP) examinees for association with likelihood of return for a second exam (rescreening). METHODS: A total of 15,733 individuals completed at least one NSSP exam before December 31, 2016; of those, 4832 also completed a second exam on or before December 31, 2019. Stepwise logistic regression models were used to identify variables associated with whether a participant was rescreened in the NSSP. RESULTS: Individuals were less likely to return for rescreening if they had a history of any cancer; cardiovascular problems; diabetes or kidney disease; or if they used insulin. Age at time of first exam and job site category significantly influenced likelihood of return. Workers categorized as "guests" were more likely to return. Participants were less likely to return if they had an abnormal urinalysis, abnormal pulmonary function, pneumoconiosis, aortic atherosclerosis, or hearing loss at their initial exam. Participants who received a chest X-ray at their initial screening were more likely to return. CONCLUSIONS: The presence of health problems is strongly linked to screening program attrition. Participants who are older at the time of their initial screening exam are less likely to return. The discovery of several strong demographic, medical, and job associations reveals the importance for medical screening programs to understand and address factors that influence participant retention and, consequently, the effectiveness of long-term health surveillance activities.

Historical perspective on the department of energy mortality studies: focus on the collection and storage of individual worker data.

PURPOSE: To present how the Department of Energy's (DOE) Comprehensive Epidemiologic Data Resource (CEDR) is integrated into the Million Person Study of Low Dose Health Effects (MPS). The history of DOE's worker health surveillance and its epidemiology program are described. METHODS AND MATERIALS: A standard protocol is used to extract data from CEDR for use in the MPS. The data files are pulled from CEDR to form the basis for the cohort analyzed in the MPS. The previous study data are reviewed to formulate the protocol for the MPS study cohort. The activities needed to update the data to construct the new analytic files are carried out in parallel. The primary efforts relate to updating the vital status, retrieving cause of death information and calculating annual radiation doses for the specific organs of interest. Working data files containing the updated data are produced for construction of analytic data files used in the biostatistical analysis. At study completion the working and analytic data files are placed into CEDR for use by other researchers. RESULTS: The use of CEDR to study the scientific and maintenance workers at the Los Alamos National Laboratory which is currently underway is used to demonstrate the process. CONCLUSIONS: There is a pressing need to answer the question of the health risk of exposure to chronic low-level exposure to ionizing radiation. Using CEDR as the starting point to identify new cohorts to include in the MPS is a cost-effective and a time efficient way to expedite answering this question.

Development and validation of a diabetes risk score among two populations.

The purpose of this study was to assess the validity of a practical diabetes risk score amongst two heterogenous populations, a working population and a non-working population. Study population 1 (n = 2,089) participated in a large-scale screening program offered to retired workers to discover previously undetected/incipient chronic illness. Study population 2 (n = 3,293) was part of a Colorado worksite wellness program health risk assessment. We assessed the relationship between a continuous diabetes risk score at baseline and development of diabetes in the future using logistic regression. Receiver operating curves and sensitivity/specificity of the models were calculated. Across both study populations, we observed that participants with diabetes at follow-up had higher diabetes risk scores at baseline than participants who did not have diabetes at follow-up. On average, the odds ratio of developing diabetes in the future was 1.38 (95% CI: 1.26-1.50, p < 0.0001) for study population 1 and 1.68 (95% CI: 1.45-1.95, p-value < 0.0001) for study population 2. These findings indicate that the diabetes risk score may be generalizable to diverse individuals, and thus potentially a population level diabetes screening tool. Minimally-invasive diabetes risk scores can aid in the identification of sub-populations of individuals at risk for diabetes.

Clinical and laboratory factors contributing to uninterpretable beryllium lymphocyte proliferation tests (BeLPT).

BACKGROUND: The beryllium lymphocyte proliferation test (BeLPT), has become the principal clinical test for detecting beryllium sensitization and chronic beryllium disease. Uninterpretable BeLPT results can occur in a small but significant proportion of tests from poor lymphocyte growth (PG) or over proliferation of lymphocytes (OP). The clinical and laboratory causes of uninterpretable results are not known. METHODS: BeLPT data from the US Department of Energy-supported Former Worker Screening Program were analyzed for a 10-year period. Drivers of uninterpretable BeLPTs were investigated using multivariable models and classification techniques. RESULTS: Three participant attributes were significantly associated with PG, while OP showed no significant associations. Serum lot for the lymphocyte growth medium accounted for 21% of the variation in PG and 16% in OP. CONCLUSION: Serum lots influence the likelihood of having uninterpretable BeLPT. To better understand uninterpretable results and possibly reduce their occurrence, additional laboratory-related factors should be addressed.

Integrated approach to health screening of former department of energy workers detects both occupational and non-occupational illness.

BACKGROUND: The National Supplemental Screening Program (NSSP) uses a Total Worker Health(TM) approach to address U.S. Department of Energy (DOE) former worker health. This article provides the design of the integrated occupational health screening and promotion program. METHODS: The NSSP implemented a web-based relational health records system to process demographic, exposure, and clinical data. We present medical findings for 12,000 DOE former workers that completed an initial NSSP medical screening between October 1, 2005 and October 4, 2013. We discuss the DOE former worker participant population and the exposure-based and non-occupational medical screening tests used. RESULTS: The NSSP identified potential occupationally related health conditions in 40.5% of those screened. Notably, we identified 85.8% of participants with addressable non-occupational health conditions, many of which were previously undiagnosed. CONCLUSION: The NSSP demonstrates that the identification of potential occupational health issues in conjunction with addressable non-occupational health conditions provides former workers with information to more effectively manage health.

Illness absences among beryllium sensitized workers.

OBJECTIVES: This study examined absence rates among US Department of Energy workers who had beryllium sensitization (BeS) or were diagnosed with chronic beryllium disease (CBD) compared with those of other workers. METHODS: We used the lymphocyte proliferation test to determine beryllium sensitivity. In addition, we applied multivariable logistic regression to compare absences from 2002 to 2011 between workers with BeS or CBD to those without, and survival analysis to compare time to first absence by beryllium sensitization status. Finally, we examined beryllium status by occupational group. Results. Fewer than 3% of the 19,305 workers were BeS, and workers with BeS or CBD had more total absences (odds ratio [OR] = 1.31; 95% confidence interval [CI] = 1.18, 1.46) and respiratory absences (OR = 1.51; 95% CI = 1.24, 1.84) than did other workers. Time to first absence for all causes and for respiratory conditions occurred earlier for workers with BeS or CBD than for other workers. Line operators and crafts personnel were at increased risk for BeS or CBD. Conclusions. Although not considered "diseased," workers with BeS have higher absenteeism compared with nonsensitized workers.

Medical screening after a coal fly ash spill in Roane County, Tennessee.

OBJECTIVE: To assess the health of community residents following a coal fly ash spill at the Tennessee Valley Authority Kingston Fossil Plant in Harriman, Tennessee, on December 22, 2008. METHODS: A uniform health assessment was developed by epidemiologists at Oak Ridge Associated Universities and medical toxicologists at Vanderbilt University Medical Center. Residents who believed that their health may have been affected by the coal fly ash spill were invited to participate in the medical screening program. RESULTS: Among the 214 individuals who participated in the screening program, the most commonly reported symptoms were related to upper airway irritation. No evidence of heavy metal toxicity was found. CONCLUSIONS: This is the first report, to our knowledge, regarding the comprehensive health evaluation of a community after a coal fly ash spill. Because this evaluation was voluntary, the majority of residents screened represented those with a high percentage of symptoms and concerns about the potential for toxic exposure. Based on known toxicity of the constituents present in the coal fly ash, health complaints did not appear to be related to the fly ash. This screening model could be used to assess immediate or baseline toxicity concerns after other disasters.

Mortality among mound workers exposed to polonium-210 and other sources of radiation, 1944-1979.

Polonium-210 is a naturally occurring radioactive element that decays by emitting an alpha particle. It is in the air we breathe and also a component of tobacco smoke. Polonium-210 is used as an anti-static device in printing presses and gained widespread notoriety in 2006 after the poisoning and subsequent death of a Russian citizen in London. More is known about the lethal effects of polonium-210 at high doses than about late effects from low doses. Cancer mortality was examined among 7,270 workers at the Mound nuclear facility near Dayton, OH where polonium-210 was used (1944-1972) in combination with beryllium as a source of neutrons for triggering nuclear weapons. Other exposures included external gamma radiation and to a lesser extent plutonium-238, tritium and neutrons. Vital status and cause of death was determined through 2009. Standardized mortality ratios (SMRs) were computed for comparisons with the general population. Lifetime occupational doses from all places of employment were sought and incorporated into the analysis. Over 200,000 urine samples were analyzed to estimate radiation doses to body organs from polonium and other internally deposited radionuclides. Cox proportional hazards models were used to evaluate dose-response relationships for specific organs and tissues. Vital status was determined for 98.7% of the workers of which 3,681 had died compared with 4,073.9 expected (SMR 0.90; 95% CI 0.88-0.93). The mean dose from external radiation was 26.1 mSv (maximum 939.1 mSv) and the mean lung dose from external and internal radiation combined was 100.1 mSv (maximum 17.5 Sv). Among the 4,977 radiation workers, all cancers taken together (SMR 0.86; 95% CI 0.79-0.93), lung cancer (SMR 0.85; 95% CI 0.74-0.98), and other types of cancer were not significantly elevated. Cox regression analysis revealed a significant positive dose-response trend for esophageal cancer [relative risk (RR) and 95% confidence interval at 100 mSv of 1.54 (1.15-2.07)] and a negative dose-response trend for liver cancer [RR (95% CI) at 100 mSv of 0.55 (0.23-1.32)]. For lung cancer the RR at 100 mSv was 1.00 (95% CI 0.97-1.04) and for all leukemias other than chronic lymphocytic leukemia (CLL) it was 1.04 (95% CI 0.63-1.71). There was no evidence that heart disease was associated with exposures [RR at 100 mSv of 1.06 (0.95-1.18)]. Assuming a relative biological effectiveness factor of either 10 or 20 for polonium and plutonium alpha particle emissions had little effect on the dose-response analyses. Polonium was the largest contributor to lung dose, and a relative risk of 1.04 for lung cancer at 100 mSv could be excluded with 95% confidence. A dose related increase in cancer of the esophagus was consistent with a radiation etiology but based on small numbers. A dose-related decrease in liver cancer suggests the presence of other modifying factors of risk and adds caution to interpretations. The absence of a detectable increase in total cancer deaths and lung cancer in particular associated with occupational exposures to polonium (mean lung dose 159.8 mSv), and to plutonium to a lesser extent (mean lung dose 13.7 mSv), is noteworthy but based on small numbers. Larger combined studies of U.S. workers are needed to clarify radiation risks following prolonged exposures and radionuclide intakes.

Exposure and genetics increase risk of beryllium sensitisation and chronic beryllium disease in the nuclear weapons industry.

OBJECTIVES: Beryllium sensitisation (BeS) and chronic beryllium disease (CBD) are caused by exposure to beryllium with susceptibility affected by at least one well-studied genetic host factor, a glutamic acid residue at position 69 (E69) of the HLA-DPß chain (DPßE69). However, the nature of the relationship between exposure and carriage of the DPßE69 genotype has not been well studied. The goal of this study was to determine the relationship between DPßE69 and exposure in BeS and CBD. METHODS: Current and former workers (n=181) from a US nuclear weapons production facility, the Y-12 National Security Complex (Oak Ridge, Tennessee, USA), were enrolled in a case-control study including 35 individuals with BeS and 19 with CBD. HLA-DPB1 genotypes were determined by PCR-SSP. Beryllium exposures were assessed through worker interviews and industrial hygiene assessment of work tasks. RESULTS: After removing the confounding effect of potential beryllium exposure at another facility, multivariate models showed a sixfold (OR 6.06, 95% CI 1.96 to 18.7) increased odds for BeS and CBD combined among DPßE69 carriers and a fourfold (OR 3.98, 95% CI 1.43 to 11.0) increased odds for those exposed over an assigned lifetime-weighted average exposure of 0.1 µg/m(3). Those with both risk factors had higher increased odds (OR 24.1, 95% CI 4.77 to 122). CONCLUSION: DPßE69 carriage and high exposure to beryllium appear to contribute individually to the development of BeS and CBD. Among workers at a beryllium-using facility, the magnitude of risk associated with either elevated beryllium exposure or carriage of DPßE69 alone appears to be similar.

Identification of an abnormal beryllium lymphocyte proliferation test.

The potential hazards from exposure to beryllium or beryllium compounds in the workplace were first reported in the 1930s. The tritiated thymidine beryllium lymphocyte proliferation test (BeLPT) is an in vitro blood test that is widely used to screen beryllium exposed workers in the nuclear industry for sensitivity to beryllium. The clinical significance of the BeLPT was described and a standard protocol was developed in the late 1980s. Cell proliferation is measured by the incorporation of tritiated thymidine into dividing cells on two culture dates and using three concentrations of beryllium sulfate. Results are expressed as a 'stimulation index' (SI) which is the ratio of the amount of tritiated thymidine (measured by beta counts) in the simulated cells divided by the counts for the unstimulated cells on the same culture day. Several statistical methods for use in the routine analysis of the BeLPT were proposed in the early 1990s. The least absolute values (LAV) method was recommended for routine analysis of the BeLPT. This report further evaluates the LAV method using new data, and proposes a new method for identification of an abnormal or borderline test. This new statistical-biological positive (SBP) method reflects the clinical judgment that: (i) at least two SIs show a 'positive' response to beryllium; and (ii) that the maximum of the six SIs must exceed a cut-point that is determined from a reference data set of normal individuals whose blood has been tested by the same method in the same serum. The new data is from the Y-12 National Security Complex in Oak Ridge (Y-12) and consists of 1080 workers and 33 non-exposed control BeLPTs (all tested in the same serum). Graphical results are presented to explain the statistical method, and the new SBP method is applied to the Y-12 group. The true positive rate and specificity of the new method were estimated to be 86% and 97%, respectively. An electronic notebook that is accessible via the Internet was used in this work and contains background information and details not included in the paper.