Mary Jean Gula

Historical cohort study of US man-made vitreous fiber production workers: I. 1992 fiberglass cohort follow-up: initial findings.

This 1986 to 1992 update and expansion of an earlier historical cohort study examined the 1946 to 1992 mortality experience of 32,110 workers employed for 1 year or more during 1945 to 1978 at any of 10 US fiberglass (FG) manufacturing plants. Included are (1) a new historical exposure reconstruction for respirable glass fibers and several co-exposures (arsenic, asbestos, asphalt, epoxy, formaldehyde, polycyclic aromatic hydrocarbons, phenolics, silica, styrene, and urea); and (2) a nested, matched case-control study of 631 respiratory system cancer (RSC) deaths in male workers during 1970 to 1992 with interview data on tobacco smoking history. Our findings to date from external comparisons based on standardized mortality ratios (SMRs) in the cohort study provide no evidence of excess mortality risk from all causes combined, all cancers combined, and non-malignant respiratory disease. Also, excluding RSC, we observed no evidence of excess mortality risk from any of the other cause-of-death categories considered. For RSC among the total cohort, we observed a 6% excess (P = 0.05) based on 874 deaths. Among long-term workers (5 or more years of employment) we observed a not statistically significant 3% excess based on 496 deaths. Among the total cohort, we observed increases in RSC SMRs with calendar time and time since first employment, but these were less pronounced among long-term workers. RSC SMRs were not related to duration of employment among the total cohort or long-term workers. In an externally controlled analysis of male workers at risk between 1970 and 1992, we observed no association between RSC SMRs and increasing exposure to respirable FG. Our findings to date from internal comparisons based on rate ratios in the case-control study of RSC were limited to analyses of categorized study variables with and without adjustment for smoking. On the basis of these analyses, the duration of exposure and cumulative exposure to respirable FG at the levels encountered at the study plants did not appear to be associated with an increased risk of RSC. RSC risk also did not seem to increase with time since first employment. There is some evidence of elevated RSC risk associated with non-baseline levels of average intensity of exposure to respirable glass, but when adjusted for smoking this was not statistically significant, and there was no apparent trend with increasing exposure. This same pattern of findings was observed for duration of exposure, cumulative exposure, and average intensity of exposure to formaldehyde. None of the other individual co-exposures encountered in the study plants appeared to be associated with an increased risk of RSC. The primary focus of ongoing analyses is to determine the extent to which our present findings are robust to alternative characterizations of exposure.

Historical cohort study of US man-made vitreous fiber production workers : II. Mortality from mesothelioma

As part of our ongoing mortality surveillance program for the US man-made vitreous fiber (MMVF) industry, we examined mortality from malignant mesothelioma using data from our 1989 follow-up of 3478 rock/slag wool workers and our 1992 follow-up of 32,110 fiberglass workers. A manual search of death certificates for 1011 rock/slag wool workers and 9060 fiberglass workers revealed only 10 death certificates with any mention of the word “mesothelioma.” A subsequent review of medical records and pathology specimens for 3 of the 10 workers deemed two deaths as definitely not due to mesothelioma and one as having a 50% chance of being caused by mesothelioma. Two other deaths, for which only medical records were available, were given less than a 50% chance of being due to mesothelioma. Eight of the 10 decedents had potential occupational asbestos exposure inside or outside the MMVF industry. We also estimated the mortality risk from malignant mesothelioma in the cohort using two cause-of-death categorizations that included both malignant and benign coding rubrics. Using the more comprehensive scheme, we observed overall deficits in deaths among the total cohort and fiberglass workers and an overall excess among rock/slag wool workers. The excess in respiratory system cancer is largely a reflection of elevated lung cancer risks that we attributed mainly to confounding by smoking, to exposures outside the MMVF industry to agents such as asbestos, or to one or more of the several co-exposures present in many of the study plants (including asbestos). The second scheme, which focused on pleural mesothelioma in time periods when specific malignant mesothelioma coding rubrics were available, classified only one cohort death as being caused by malignant mesothelioma, compared with 2.19 expected deaths (local county comparison). We conclude that the overall mortality risk from malignant mesothelioma does not seem to be elevated in the US MMVF cohort.

Employment as a welder and parkinson disease among heavy equipment manufacturing workers

Objective: We investigated whether employment as a welder with potential exposure to manganese and other substances is associated with Parkinson disease (PD), parkinsonism or related neurological disorders, or accelerates the age of onset of PD. Methods: We selected cases and controls from 12,595 persons ever employed at three Caterpillar Inc. (CAT) plants between 1976 and 2004 with potential to make a medical insurance claim between 1998 and 2004. Cases had filed a claim for 1) PD, 2) “secondary parkinsonism”, 3) “other degenerative diseases of the basal ganglia” or 4) “essential and other specific forms of tremor”. Cases were grouped by claims: Group 1-claims 1 and 2 and Group 2-claims 1 to 4, and as study period incident (SPI) or prevalent. Each case was matched to two series of 10 controls each on date of case’s first claim, year of birth, race and sex. Series I was also matched on plant. Results: Odds ratios (OR) and 95% confidence intervals (CI) for the variable, “ever welder in any CAT plant” were: Group 1-SPI Cases: Series I (OR = .76, CI = .26–2.19), Series II (OR = .81, CI = .29–2.25); Group 1- Prevalent Cases: Series I (OR = .82, CI = .36–1.86), Series II (OR = .97, CI = .42–2.23); Group 2- SPI Cases: Series I (OR = 1.03, CI = .57–1.87), Series II (OR = 1.21, CI = .67–2.20) Group 2-Prevalent Cases: Series I (OR = 1.02, CI = .62–1.71), Series II (OR = .86, CI = .51–1.43). Our finding of no statistically significant associations for welding employment was maintained following adjustment for potential confounding and evaluation of possible effect modification. Employment as a welder did not accelerate the age of onset of PD. Conclusions: Our study supported the conclusion that employment as a welder is not associated with Parkinson disease, parkinsonism or a related neurological disorder.

Indolent course of advanced neuroblastoma in children older than 6 years at diagnosis

Background. An early observation suggests that children older than 6 years of age at diagnosis of neuroblastoma constitute a favorable prognostic group.

Historical cohort study of US man-made vitreous fiber production workers: VII. Overview of the exposure assessment.

Data and procedures used to reconstruct the history of exposures at each of the 15 plants (19 distinct sites) are presented. The assessment consisted of five steps: (1) develop a Technical History of operations, stable periods, and time points of changes relevant for exposures, and identify the presence of potentially confounding co-exposures; (2) develop a set of unique department-job names with descriptions and a Job Dictionary for all verbatim names in work histories; (3) collect all company and other exposure data (>1600 observed), and develop quantitative fiber, formaldehyde, and silica exposure estimates; (4) integrate estimates with the Technical History to make Exposure Extrapolation Tables; and (5) use the the Tables with job data to develop an Exposure Matrix for each plant. Nineteen Exposure Matrices were made, with 82 to 621 lines, covering up to 54 years of operations.

Historical cohort study of US man-made vitreous fiber production workers: VIII. Exposure-specific job analysis.

All jobs held by a cohort of US man-made vitreous fiber production workers were analyzed for airborne fiber exposure. This exposure-specific job analysis was part of an exposure assessment for an epidemiologic study of mortality patterns, with particular focus on respiratory cancer, among 35,145 workers employed in 10 fiberglass and five rock or slag wool plants. The exposure assessment was conducted from the start-up date of each plant (1917 to 1946) to 1990. For the job analysis, 15,465 crude department names and 47,693 crude job titles were grouped into 1668 unique department and job pairs (UDJobs), which represented a job title linked to a specific department within each plant. Every UDJob was evaluated according to a set of job elements related to airborne fiber exposure. The distribution of the cohort person-years by UDJob and the job-exposure elements was then evaluated. The results show the main departments and jobs that employed the workers for each plant. The distribution of person-years varies across the job-exposure elements. The same job title was used in different departments within and across plants. When job titles not linked to departments were evaluated, the values of the job-exposure elements varied considerably across all plants and within plant. In conclusion: (1) exposure misclassification could occur if job title alone were used for the exposure assessment; (2) the job-exposure elements analysis provides an efficient way to identify major job determinants of exposure without relying on the more detailed, resource-intensive task-based approach; and (3) the evaluation of the cohort person-years by UDJobs and job-exposure elements is an effective way to identify which plants, departments, and jobs have sufficient information for making precise risk estimates in the broader epidemiologic study.

Mortality among chemical plant workers exposed to acrylonitrile and other substances

OBJECTIVES To examine the association between exposure to acrylonitrile (AN) and cancer mortality by performing an independent and extended historical cohort study of workers from a chemical plant in Lima, Ohio included in a recent NCI-NIOSH study. METHODS Subjects were 992 white males who were employed for three or more months between 1960 and 1996. We identified 110 deaths and cause of death for 108. Worker exposures were estimated quantitatively for AN and qualitatively for nitrogen products. Statistical analyses included U.S. and local county-based SMRs and internal relative risk regression of internal cohort rates. RESULTS No statistically significant excess mortality risks were observed among the total cohort for the cancer sites implicated in previous studies: stomach, lung, breast, prostate, brain, and hematopoietic system. We observed a statistically significant bladder cancer excess based on four deaths (SMR=7.01, 95% CI=1.91-17.96) among workers not exposed to AN. Among 518 AN-exposed workers, we observed a not statistically significant excess of lung cancer based on external (SMR=1.32, 95% CI=.60-2.51) and internal (RR=1.98, 95% CI=.60-6.90) comparisons. Although the trends were not statistically significant, exposure-response analyses of internal cohort rates showed monotonically increasing lung cancer rate ratios with increasing AN exposure, with RRs exceeding 2.0 in the highest exposure categories. CONCLUSIONS With the possible exception of lung cancer, this study provides little evidence that exposure to AN at levels experienced by Lima plant workers is associated with an increased risk of death from any cause including the implicated cancer sites.

A Case-Control Study of Lung Cancer Mortality in Four Rural Arizona Smelter Towns

To investigate factors related to lung cancer mortality in four Arizona copper-smelter towns, the authors identified 142 lung cancer cases and 2 matched controls per case from decedent residents during 1979-1990. The authors obtained detailed information on lifetime residential, occupational, and smoking histories via structured telephone interviews with knowledgeable informants. The authors linked estimated historical environmental exposures to smelter emissions (based on atmospheric diffusion modeling of measured sulfur dioxide concentrations) with residential histories to derive individual profiles of residential exposure. The results of this study provided little evidence of a positive association between lung cancer and residential exposure to smelter emissions. Conditional logistic regression analysis revealed a statistically significant positive association between lung cancer and reported employment in copper mines and/or smelters, although specific factors associated with the apparently increased risk among these workers could not be identified in this community-based study.

Relapse in acute lymphoblastic leukemia as a function of white blood cell and absolute neutrophil counts during maintenance chemotherapy.

Several reports document an inverse correlation between bioavailability of maintenance chemotherapeutic agents and the likelihood of relapse in childhood. White blood cell counts (WBC) and absolute neutrophil counts (ANC) are easily ascertainable parameters which might be expected to reflect plasma levels of chemotherapy. To determine whether WBC and ANC predict outcome of children with acute lymphoblastic leukemia (ALL), we did a multivariate analysis of means of these values during maintenance therapy in patients with ALL treated on a single protocol. Of the 52 patients, 15 (29%) relapsed. For those still disease-free, minimum time of follow-up is 7-8/12 years. During the first year of maintenance therapy, mean WBC (x 10(3)/mm3) in the relapsed and nonrelapsed groups were 4.5 +/- 0.9 and 3.9 +/- 0.7, respectively (p = 0.03); mean ANC (x 10(3)/mm3) were 3.0 +/- 0.9 and 2.5 +/- 0.6 (p = 0.05). However, the range of values was large with considerable overlap between the two groups. There was no obvious difference in distribution of values when confounding prognostic features were adjusted for in the analysis. No significant differences were seen between WBC or ANC during the second year of therapy. Larger numbers of patients will be needed to ascertain whether specific guidelines for dosage modifications can be made on the basis of serial WBC. Future pharmacokinetic studies should look at possible correlations with mean WBC and ANC.

ED security: a national telephone survey

To determine current practices regarding security measures in the emergency department (ED), a random sample of 250 hospitals with EDs was surveyed by telephone. Security issues addressed included personnel (in-house security, contract guards, or police), hours of staffing in the ED, how security is armed, whether ED doors are locked at off-hours, and whether alarm buttons, direct phone lines, a paging code, closed circuit surveillance, metal detectors, and seclusion rooms are used. This information was stratified according to hospital size, ED census, rural/suburban/urban setting, teaching/nonteaching status, and region. Generally, on-site security presence increases with increasing hospital size and ED census, suburban and urban locations, and teaching status. Small, rural hospitals are more likely to lock the ED doors at off-hours, whereas the use of security codes does not clearly follow demographic trends. Larger hospitals in suburban and urban settings and having a teaching status are more likely to have secure/detention rooms and closed circuit surveillance. The use of alarm buttons and/or direct telephone lines varies widely, but is generally more common in larger, teaching hospitals, located in urban and suburban settings.