bluuebunny/crossref_metadata_2025 huggingface dataset:
Asthma, lung function, and bronchial responsiveness in welders
Authors: Wang Zhi Ping , Larsson Kjell , Malmberg Per , Sjögren Bengt , Hallberg Bengt‐Olov , Wrangskog Kent
Published: April 2007

The incidence of asthma was compared in welders welding in stainless steel (SS) or mild steel (MS). The study was comprised of welders who had been welding for at least 6 months during the preceding 10 year period in four companies, but who had not been welding occupationally prior to this time. The inclusion criteria were met by 42 SS welders with a total welding time of 196 years. Sixteen of these had left work, six because of airway symptoms. Eighty‐five MS welders with a total welding time of 403 years were included. Forty‐eight of these had left work, 10 citing airway symptoms as a main reason for leaving work, according to responses in a mailed questionnaire. Ex‐welders with airway symptoms were in some cases further investigated with spirometry and bronchial provocation tests. In other cases, medical records gave a clear diagnosis.

In addition, bronchial responsiveness and lung function were measured and airway symptoms were recorded in presently active welders. Twenty‐three of the 26 active SS steel welders and 23 of the 37 active MS steel welders were examined, together with a reference group of 26 (out of 30 invited) vehicle assemblers.

There was no difference in the incidence of welding‐associated asthma (5% for SS, 7% for MS welders per 1,000 welding‐years). Bronchial responsiveness and lung function in active welders was normal and did not differ between MS and SS welders or between welders and a reference group of vehicle fitters. Welders had a significantly higher prevalence of airway symptoms as compared to vehicle fitters.
Asbestos‐induced lung injury among danish jewelry workers
Authors: Døssing Martin , Langer Seppo W.
Published: April 2007

Asbestos has been used extensively in a variety of occupations. In the jewelry industry, inadequate hygiene practices may often go unrecognized with resultant exposure to hazardous amounts of asbestos. We report on four retired jewelers. Two of these had both pleural and parenchymal changes. One had isolated pleural plaques and the final patient showed only parenchymal infiltrates. Their work involved hand cutting asbestos plates used for protection during soldering. In the soldering process asbestos fibers were then blown into the workroom air as the plates broke down. In addition, at the end of each work day the workroom floor was swept, with subsequent airborne asbestos dust distribution. Any patient with pleural plaques or interstitial lung disease should be questioned about potential sources of asbestos exposure in the past, regardless of present employment status.
Respiratory symptoms and lung function in bus drivers and mechanics
Authors: Zuskin Eugenija , Mustajbegovic Jadranka , Schachter E. Neil
Published: April 2007

Acute and chronic respiratory symptoms as well as ventilatory capacity were studied in 116 bus drivers and 119 mechanics. Bus drivers and mechanics demonstrated a significantly higher prevalence of most chronic respiratory symptoms when compared to control workers. In particular, lower airway symptoms of chest tightness and dyspnea and upper airway symptoms of nasal catarrh were significantly more prevalent among drivers and mechanics than among controls. Bus drivers and mechanics who were smokers had significantly higher prevalences of respiratory symptoms than nonsmoking bus drivers. Bus drivers and mechanics employed for more than 10 years also exhibited higher frequencies of respiratory symptoms than those exposed for 10 years or less. Many of the workers complained of acute symptoms during the work shift. The ventilatory capacity data demonstrated lower values for all parameters, particularly FEF25, compared to control worker values as well as to predicted normal values, for bus drivers and mechanics who were smokers.

Our data indicate that long‐term employment in the transport industry of bus drivers and mechanics, particularly in combination with smoking, may be associated with the development of chronic respiratory symptoms and lung function impairment.
Mortality among urban policemen in Rome
Authors: Forastiere Francesco , Perucci Carlo A. , di Pietro Antonio , Miceli Maria , Rapiti Elisabetta , Bargagli Annamaria , Borgia Piero
Published: April 2007

A total of 3,868 urban policemen in Rome were investigated through a historical cohort study with emphasis on mortality from cardiovascular disease and cancer. Overall mortality from cardiovascular disease, respiratory conditions, digestive and genitourinary diseases, and accidents was lower than expected. An excess risk of ischemic heart disease was observed among subjects aged less than 50 years [14 deaths, standardized mortality ratio (SMR = 1.63), 95% CI = 0.89–2.73], corresponding to workers with a short duration of employment and a short latency since first employment. Overall cancer mortality was as expected and no excess was found for lung cancer (82 deaths, SMR = 1.05). Increased mortality was observed from colon cancer (16 deaths, SMR = 1.47), melanoma (four deaths, SMR = 2.34), bladder cancer (13 deaths, SMR = 1.27), renal cancer (seven deaths, SMR = 1.39), and non‐Hodgkin's lymphoma (six deaths, SMR = 1.51), although none of the excesses were statistically significant. Two deaths from male breast cancer (SMR = 14.36) and three from cancer of endocrine glands were found (SMR = 3.44). Nested case‐control studies were conducted to evaluate cancer mortality risk by job category. Bladder cancer was significantly increased among car drivers (OR = 4.17); for kidney cancer, an increased odds ratio (OR = 2.27) was found among motorcyclists; non‐Hodgkin's lymphoma clustered among motorcyclists (OR = 5.14). In summary, excess risk for specific cancer sites (colon, male breast, and endocrine glands) might be linked to occupational exposures; professional drivers seem to be at higher risk of bladder cancer, kidney cancer, and non‐Hodgkin's lymphoma.
Fatal asthma in a baker: A case report
Authors: Ehrlich Rodney I.
Published: April 2007

A case of baker's asthma with a fatal outcome is described. Clinical features and the circumstances of death are recounted. While the case documents the potential severity of occupational asthma, it also illustrates the difficulties of managing occupational asthma in the absence of good social security.
Asbestos‐related disease associated with exposure to asbestiform tremolite
Authors: Srebro Sharon H. , Roggli Victor L.
Published: April 2007

Tremolite is nearly ubiquitous and represents the most common amphibole fiber in the lungs of urbanites. Tremolite asbestos is not mined or used commercially but is a frequent contaminant of chrysotile asbestos, vermiculite, and talc. Therefore, individuals exposed to these materials or to end‐products containing these materials may be exposed to tremolite. We have had the opportunity to do asbestos body counts and mineral fiber analysis on pulmonary tissue from five mesothelioma cases and two asbestosis cases with pulmonary tremolite burdens greater than background levels. There were no uncoated amosite or crocidolite fibers detected in any of these cases. Three patients were occupationally exposed to chrysotile asbestos; two patients had environmental exposures (one to vermiculite and one to chrysotile and talc) and one was a household contact of a shipyard worker. The tremolite burdens for the asbestosis cases were one to two orders of magnitude greater than those for the mesothelioma cases. Our study confirms the relationship between tremolite exposure and the development of asbestos‐associated diseases. Furthermore, the finding of relatively modest elevations of tremolite content in some of our mesothelioma cases suggests that, at least for some susceptible individuals, moderate exposures to tremolite‐contaminated dust can produce malignant pleural mesothelioma.
Workers' compensation for nonmalignant asbestos‐related lung disease
Authors: Nevitt Courtney , Daniell William , Rosenstock Linda
Published: April 2007

Workers' compensation claims filed for occupational illness are generally more complicated to resolve than are injury claims, and they may therefore face higher likelihood of rejection. This study analyzed outcomes and predictive factors for claims filed from one clinic in Washington State between 1982 and 1986 by 157 male patients for non‐malignant asbestos‐related lung disease. Among 50 federal Longshore claims, 46 (92%) were unresolved or could not be located by claims administrators. In contrast, 118 (89%) of State Fund claims had been resolved, with 48% accepted without consistent relationship to disease severity. Claims filed under both jurisdictions showed a twofold greater risk of rejection by the State Fund (relative risk, RR = 2.0; 95% confidence interval, 95% CI = 1.3–3.2). State Fund claims filed for nonwhite patients were rejected more often than those of white patients, although the association was explained at least partially by jurisdictional overlap (adjusted RR = 1.5;95% CI = 1.05–2.1). This study indicates a need to scrutinize the handling of occupational disease claims by the federal Longshore system and to consider the adverse influences of jurisdictional conflicts and possible race‐associated factors on compensation of occupational illness.
Critical issues for agrichemical safety in South Africa
Authors: London L. , Myers J. E.
Published: April 2007

A review is made of the potential for environmental and occupational exposure to agrichemicals in South Africa. Data from the farming industry in the Western and Southern Cape regions of South Africa confirm substantial use of a range of insecticides, fungicides, and other agrichemicals. The potential for worker exposure to hazardous agrichemicals is also substantial but, to date, such exposures have been poorly characterized. Further data identify important deficiencies in industrial hygiene measures with regard to safekeeping of chemicals on farms, disposal of empty containers, use of protective equipment, and levels of safety training among farm workers. Evidence is presented for widespread underreporting of agrichemical morbidity and mortality. Surveys investigating acute health effects among farm workers with occupational exposure to agrichemicals in South Africa have produced conflicting results. The possibility of chronic health sequelae from low‐dose long‐term exposure is an underresearched area that is only now being investigated. A number of important obstacles to agrichemical safety are identified: the multiplicity of laws relating to pesticides administered by different departments resulting in poor coordination; the failure of existing occupational health legislation to address the agricultural workplace adequately; the unavailability and incoordination of safety training; the absence of adequate surveillance data; and inadequacies in statutory requirements with regard to waste disposal on farms. Drawing on experiences of local initiatives, possible solutions are identified that address the public health context of the problem.
PMR study of mortality among Alabama workers and farmers
Authors: Austin Susan G. , Huang Ningyi , Woernle Charles W.
Published: April 2007

Computerized records of all Alabama deaths occurring to persons 16 years of age and over for the 5‐year period 1984‐1988 were obtained from the Alabama Department of Public Health. Using proportionate mortality ratio (PMR) methodology and death certificate occupation, cause‐specific mortality patterns were examined for all Alabama decedents (N = 182,178), for all Alabama workers (N = 125,369), and for the occupational group of “farm operators and managers” (N = 11,691). In comparison with the U.S. general population, little difference was found between cause‐specific PMR results for the total Alabama population and those for all workers, suggesting the absence of a generalized “healthy worker effect.” In comparison with the U.S. population, PMR results for farmers suggested lowered mortality from all malignant neoplasms and all heart disease, and elevated mortality from all external causes of death. In comparison with the Alabama population, PMR results for farmers continued to suggest lowered mortality from all malignant neoplasms, specifically for cancers of the respiratory, digestive and lymphopoietic systems. However, significantly elevated PMRs for external causes of death appeared only among nonwhite female farmers. Further investigation of these deaths suggested that this finding was more likely attributable to an increased risk of housefire deaths associated with rural lifestyle than with occupational factors.
Suicide, cancer, and other causes of death among california veterinarians, 1960‐1992
Authors: Miller Joy M. , Beaumont James J.
Published: April 2007

Previous studies reporting on mortality patterns in veterinarians have been restricted to deaths among white male veterinarians. In an effort to examine the mortality of male and female veterinarians of all races, we conducted a standardized proportionate mortality ratio (SPMR) analysis of 450 California veterinarians who died between January 1960 and December 1992. In comparison to State of California general population statistics, white male veterinarians had significantly elevated mortality from malignant melanoma of the skin (SPMR 3.47, 95% CI 1.74. 6.94), cancer of the large intestine (SPMR 1.74, 95% CI 1.04, 2.09), rheumatic heart disease (SPMR 3.50, 95% CI 1.90, 6.43), and suicide (SPMR 2.50, 95% CI 1.84, 3.38). White female veterinarians had significantly elevated mortality from suicide (SPMR 5.89, 95% CI 3.02, 11.48). We also examined veterinary mortality for different lengths of time in the profession. Significantly elevated SPMRs were noted for suicide in veterinarians in the profession for less than 30 years; deaths due to malignant melanoma of the skin and rheumatic heart disease in veterinarians in the profession 20 years or more; and cancer of the large intestine in veterinarians in the profession 30 years or more. Because of significant findings in mortality from suicide among veterinarians of both sexes, it was recommended that future studies and efforts toward suicide prevention include both male and female veterinarians.
Work‐related fatalities in the agricultural production and services sectors, 1980‐1989
Authors: Myers John R. , Hard David L.
Published: April 2007

A total of 6,727 workers died of work‐related injuries in the agricultural production and agricultural services sectors between 1980 and 1989, as established by data from the National Institute for Occupational Safety and Health (NIOSH) National Traumatic Occupational Fatalities (NTOF) surveillance system. The agricultural production sector accounted for the higher fatality rate (22.9 deaths per 100,000 workers), due largely to deaths caused by machinery and motor vehicles. The leading cause of death in the agricultural services sector was being struck by falling objects, primarily trees. Fatality rates were highest in the East South Central United States and lowest in the New England states. Blacks had the highest fatality rate (26.4 deaths per 100,000 workers) while workers other than white or black had the lowest rate (18.9 per 100,000 workers). Males were at higher risk of death than females, with the 65 years of age and older male group having the highest rate (60.5 deaths per 100,000 workers). Males 16‐24 years of age exhibited the largest decrease in their average annual fatality rate during the 10‐year period, down to 7.2 from 20.6 deaths per 100,000 workers. Possible reasons for this decrease are suggested.
Bronchial reactivity and work‐related symptoms in farmers
Authors: Carvalheiro Maria Fernanda , Peterson Yvonne , Rylander Ragnar
Published: April 2007

Work‐related respiratory symptoms and bronchial reactivity were studied in 76 never‐smoking farmers and in a control group not exposed to organic dusts. The farmers were divided into those working with vegetables/grain crops, animals but not swine, and with swine. The extent of symptoms was evaluated using a specific organic dust questionnaire. Bronchial reactivity was assessed with the methacholine challenge test. An increased incidence of organic dust toxic syndrome (ODTS), mucous membrane irritation (MMI), and chronic bronchitis (CB) was found among farmers working with swine or other animals. Pulmonary function baseline values were normal. Bronchial reactivity was increased and related to subjective symptoms of MMI and CB. There was also a relation between fatigue at work and bronchial reactivity.
Relations between upper limb soft tissue disorders and repetitive movements at work
Authors: English C. J. , Maclaren W. M. , Court‐Brown C. , Hughes S. P. F. , Porter R. W. , Wallace W. A. , Graves R. J. , Pethick A. J. , Soutar C. A.
Published: April 2007

To make a preliminary assessment of whether upper limb soft tissue disorders might be associated with activities at work, we have conducted a case‐control study of subjects attending orthopedic clinics in three cities. All subjects between the ages of 16 and 65 years, in whom defined soft tissue conditions of the upper limb were diagnosed by the participating orthopedic surgeons, were invited to take part. Controls were subjects attending the same clinics within the same age range whose clinical diagnosis did not include disease of the upper limb, cervical or thoracic spine. Information concerning repetitive movements of the upper limbs at work was elicited by questionnaire. Five hundred eighty cases and 996 controls were studied, representing 96% and 93%, respectively, of those invited to participate. The diagnoses of the cases included soft tissue conditions affecting the shoulder, elbow, forearm, wrist, thumb, hand, and fingers. The diagnoses of the controls included traumatic, degenerative, and inflammatory conditions, mostly of the legs and lower back. Women predominated among the cases (70%) and men among the controls (56%). Of 221 female cases with injury to the wrist and forearm, 32 were cleaner/domestics (14.5%) compared to 35 of 439 controls (8%), a difference statistically significant at the 2 1/2% level. Other jobs significantly overrepresented (5% level) among female cases with injuries at various anatomical sites included hairdressers, secretary/temps, assembly line workers, and machine operators (type unspecified). Among male cases, electricians were significantly overrepresented (5% level). Jobs for which there was a suggestion (p < 0.1) of overrepresentation among cases included butchers and teacher/ lecturers (both males only) and the combined job groups (chosen a priori for analysis) of keyboard operators, machine operators, and music teachers (all three jobs, females only).
Experimental Evaluation of the Effect of Filtration of Diesel Exhaust by Biologic Exposure Indicators
Authors: Ulfvarson Ulf , Dahlqvist Monica , Sandström Thomas , Bergström Björn , Ekholm Ulla , Lagerstrand Lars , Figler Barbara , Nilsen Asbjørn , Bjermer Leif , Trønnes Torkel , Nilsen Odd G.
Published: April 2007

The airway resistance, compliance of the respiratory system, transfer factor, and alveolar volume of 33 healthy rabbits were studied before and after exposure to diluted diesel exhaust generated in an experimental motor. Three diesel fuels and two particle traps were tested. Subsequent to the post‐exposure lung function measurements, the animals were sacrificed and the lungs were processed for morphologic examination. The concentrations of particles, nitrogen dioxide, and formaldehyde were measured. The inflammatory airway changes were most pronounced in animals exposed to exhaust from standard fuel. Small changes were identified in animals exposed to exhaust filtered through the catalytic trap as well or exposed to unfiltered exhaust from fuels intended for densely built‐up areas. Increase in compliance of the respiratory system was associated with the concentration of soot particles and formaldehyde. Compliance decreased significantly in animals exposed to exhaust from standard fuel filtered through the particle traps and increased almost significantly in animals exposed to unfiltered exhaust from the same fuel.
Pneumoconiosis and Associated Medical Conditions
Authors: Rosenman Kenneth D. , Zhu Zhiwei
Published: April 2007

Hospital discharge data from Michigan for the years 1990 and 1991 were used to examine potential associations between pneumoconiosis and pulmonary hypertension, lung cancer, obstructive lung disease, and connective tissue disease among both men and women. Lung cancer, pulmonary hypertension, and obstructive lung disease were associated with coal workers' pneumoconiosis. Pulmonary hypertension and obstructive lung disease were associated with asbestosis and silicosis. Rheumatoid arthritis was associated with silicosis. The potential is suggested that misdiagnosis is the cause of the association between lung cancer and coal workers' pneumoconiosis.
Asbestos‐related diseases in construction carpenters
Authors: Garcia‐Closas Montserrat , Christiani David C.
Published: April 2007

To assess the association of minimal parenchymal fibrosis and pleural plaques with respiratory functional impairment, we conducted a survey of 631 asbestos‐exposed construction carpenters. This population had a relatively low prevalence of radiographic abnormalities and lung function impairment. Pleural plaques was the asbestos‐related disease most prevalent, followed by interstitial fibrosis with predominantly low profusion scores. The most frequent functional impairment was the obstructive pattern, followed by restrictive and mixed patterns.

After adjusting for potential confounders, the presence of pleural plaques was significantly associated with a mixed respiratory pattern of impairment (OR = 3.7, 95% CI 1.4‐12.3). Furthermore, our data were consistent with a weak association between pleural plaques and a predominately restrictive defect (OR—1.3, 95% CI 0.4‐3.9). This study also suggested an association between minimally detectable profusions and both obstructive (OR = 1.9, 95% CI 0.6‐6.3) and mixed (OR = 1.6, 95% CI 0.3‐7.1) defects. Although only 631 of a potential 7,649 active and retired union members participated in this first‐time survey and were relatively young, these findings add new evidence to the functional importance of pleural fibrosis and minimal parenchymal fibrosis. © 1995 Wiley‐Liss, Inc.
Prevalence of pneumoconiosis and its relationship to dust exposure in a cohort of U.S. Bituminous coal miners and ex‐miners
Authors: Attfield Michael D. , Seixas Noah S.
Published: April 2007

Information on radiographic evidence of coal workers' pneumoconiosis (CWP) is presented for a group of 3,194 underground bituminous coal miners and ex‐miners examined between 1985 and 1988. Prevalence of CWP was related to estimated cumulative dust exposure, age, and rank of coal. On the basis of these data, miners of medium to low rank coal, who work for 40 years at the current federal dust limit of 2 mg/m3, are predicted to have a 1.4% risk of having progressive massive fibrosis on retirement. Higher prevalences are predicted for less severe categories of CWP. Miners in high rank coal areas appear to be at greater risk than those mining medium and low rank coals. Ex‐miners who said that they left mining for health‐related reasons had higher levels of abnormality compared to current miners.
Modeling epidemiologic studies of occupational cohorts for the quantitative assessment of carcinogenic hazards
Authors: Stayner Leslie , Smith Randy , Bailer A. John , Luebeck E. Georg , Moolgavkar Suresh H.
Published: April 2007

Epidemiologic studies of occupational cohorts have played a major role in the quantitative assessment of risks associated with several carcinogenic hazards and are likely to play an increasingly important role in this area. Relatively little attention has been given in either the epidemiologic or the risk assessment literature to the development of appropriate methods for modeling epidemiologic data for quantitative risk assessment (QRA). The purpose of this paper is to review currently available methods for modeling epidemiologic data for risk assessment. The focus of this paper is on methods for use with retrospective cohort mortality studies of occupational groups for estimating cancer risk, since these are the data most commonly used when epidemiologic information is used for QRA. Both empirical (e.g., Poisson regression and Cox proportionate hazards model) and biologic (e.g., two‐stage models) models are considered. Analyses of a study of lung cancer among workers exposed to cadmium are used to illustrate these modeling methods. Based on this example it is demonstrated that the selection of a particular model may have a large influence on the resulting estimates of risk.
Occupational epidemiology in the rubber industry: Implications of exposure variability
Authors: Kromhout Hans , Heederik Dick
Published: April 2007

The variability of exposure has important implications for the design of occupational epidemiologic studies. To assess the influence of this variability in the rubber industry, the efficiency of different schemes for classification of exposure to particulates, cyclohexane‐soluble contaminants, and solvents was assessed. Groupings based on job title, plant, factors affecting exposure, published classifications, and the International Standard Classification of Occupations of the International Labor Organization (ISCO‐ILO) were compared. Statistical parameters for contrast in average exposure between groups and precision of average exposure within groups were developed to enable comparison of the efficiency of different classification schemes.

Grouping of exposure to particulates and dermal exposure appeared to be less efficient than grouping of exposure to solvents. Grouping of solvent exposure using occupational title groups, existing classification schemes, and schemes based on factors affecting exposure showed comparable high resolution in exposure levels. Even the most detailed grouping schemes based on the combination of plant and occupational title group showed relatively modest resolution in particulate and dermal exposure levels. Groupings based on factors affecting exposure showed similar resolution for these exposures, but had higher precision due to having fewer groups.

Application of optimal exposure grouping strategies will benefit new research on cancer among rubber workers. Eventually, this might resolve the situation in which a complete industry was included on the list of proven human carcinogens.
Cancer incidence among seamen in iceland
Authors: Rafnsson Vilhjálmur , Gunnarsdóttir Hólmfridur
Published: April 2007

The cancer incidence was investigated among 27,884 fishermen and sailors from the merchant fleet who had been members of a pension fund for seamen during 1958‐1986 in Iceland. The cancer incidence was followed through 1966‐1988. Expected values were based on rates for the general male population in Iceland. In the whole cohort, 758 malignant neoplasms had occurred as compared to 688.43 expected, standardized incidence ratio (SIR) = 1.10, 95% confidence limit (CI) 1.03‐1.18. There was an excess for cancer of the stomach, rectum, larynx, and lung and nonmelanoma skin cancer; the SIRs were 1.29, 1.44, 1.77, 1.61, and 1.51, respectively. When analyzing the cancer incidence according to length of employment, the SIRs for many of the cancer sites were high for those with a short employment and many SIRs decreased with increasing length of employment. The SIRs for lung cancer were high in all subgroups. Only for stomach cancer and leukemia was there a substantial increase in SIR with increasing length of employment. The SIR was 1.55 for stomach cancer (CI 1.01‐2.27) in the group with longer than 10 years of employment, and 1.97 for leukemia (CI 0.85‐3.87) in the same group. It is concluded that the risk of both stomach and lung cancer seems to be associated with the occupation of seamen.
Associations between disease and occupation: Hypotheses generated from the national mortality followback survey
Authors: Reviere Rebecca , Schneider Scott , Woolbright Kathy
Published: April 2007

This study uses the National Mortality Followback Survey of 1986 to identify the top five Sentinel Health Events Occupational [SHE(O)s], the five leading causes of death, and to ascertain the primary occupations and industries associated with these. We found that, as expected, cardiovascular diseases were four of the five leading causes of death overall. In addition, the SHE(O) responsible for most deaths was cancer of the trachea, bronchus, and lung, followed by renal failure, bladder cancer, myeloid leukemia, and liver cancer. We employed proportionate mortality ratios to analyze the relationship between industry and occupation and category of mortality. In brief, we validated findings by other researchers; for example, farmers were at lower risk of cancer of the trachea, bronchus, and lung, and workers in eating/ drinking places had excess risk of liver cancer. We also hypothesize other relationships, such as between motor vehicle dealers and bladder cancer.
Quantitative comparison of asbestos and talc bodies in an individual with mixed exposure
Authors: Dodson Ronald F. , O'Sullivan Michael , Corn Carolyn J. , Hammar Samuel P.
Published: April 2007

Tissue from an individual with a history of exposure to asbestos and other dust was referred for particulate analysis. The digested material was reviewed by light microscopy to establish the numbers of ferruginous bodies per gram of tissue. Typical asbestos bodies were found at levels consistent with occupational exposure. A second type of elongated ferruginous body was formed on a thicker transparent core which suggested the minerals were sheet silicates. The number of ferruginous bodies with nonasbestos cores was over four times the number of asbestos cored ferruginous bodies.

Electron microscopy was used to confirm the core composition of both populations and also to establish the levels of uncoated fibers. The nonasbestos ferruginous bodies were predominantly formed on talc.
Comparison of neurobehavioral function in workers exposed to a mixture of organic and inorganic lead and in workers exposed to solvents
Authors: Bolla Karen I. , Schwartz Brian S. , Stewart Walter , Rignani Joellen , Agnew Jacqueline , Ford D. Patrick
Published: April 2007

The neurobehavioral effects of lead (organic and inorganic) and organic solvents were compared in 386 U.S. workers (52 reference, 190 lead, and 144 solvent workers). The association between neurobehavioral test performance and duration of exposure to lead or solvents was also examined and compared. The neurobehavioral test battery consisted of examiner and computer‐administered neurobehavioral tests, a test of olfactory function, and questionnaires that assessed neuropsychiatric symptoms. Adjusted mean differences on the neurobehavioral test scores were estimated by comparing the exposed group to the referent group using linear regression and adjusting for premorbid intellectual ability, age, and race. Both lead and solvents were associated with diminished neurobehavioral performance in all neurobehavioral areas tested. Specifically, while lead and solvent exposure had the same magnitude of adverse effects on tests of manual dexterity, lead exposure was associated with greater adverse effects on memory and learning tests but with less adverse effects on executive/motor tests and on a test of olfaction than solvent exposure. An elevated number of neuropsychiatric symptoms was reported by 7% of the referent group, 43% of the lead group, and 15% of the solvent group. For exposure duration of ⩾10 years, more neurobehavioral decrements were found in the solvent group relative to the lead group. However, for exposure duration of ⩽18 years, the lead group showed more decrements than the solvent group. Overall, these data suggest differences in neurobehavioral functioning between the lead (organic and inorganic) and solvent exposed workers examined in this study.
Insulation, asbestos, smoking habits, and lung cancer cell types
Authors: Muscat Joshua E. , Stellman Steven D. , Wynder Ernst L.
Published: April 2007

The association between occupational exposure to asbestos and histological type of lung cancer was analyzed in a multicenter hospital‐based case‐control study (2,871 male cases and 5,240 male controls) conducted from 1981‐1991. Twenty‐two percent of cases and 18% of controls were employed in asbestos‐related occupations for at least 1 year. Most of these asbestos jobs were in the construction field. The odds ratio (OR) among current smokers was 1.0 [95% confidence intervals (CI) 0.9 to 1.3]; for ex‐smokers, the OR was 1.4 (95% CI 1.1 to 1.6). In contrast, 10% of cases and 5% of controls self‐reported that they were chronically exposed to asbestos for at least 1 year. Self‐reported asbestos exposure was significantly related to all lung cancer cell types among smokers and ex‐smokers, although a trend in the ORs with duration of self‐reported exposure was not found for current smokers. Among 48 cases and 52 controls reporting distinct exposure to building insulation, the OR was 2.2 (95% CI 1.2 to 4.3) for current smokers, and 1.8 (95% CI 0.9 to 3.6) for ex‐smokers, compared to subjects who were not exposed to building insulation and asbestos. A nonsignificant association with self‐reported exposure to asbestos was observed for a small number of never smokers (eight of 83 nonsmoking cases, OR = 2.0, 95% CI 0.9 to 4.6). When examining these results and their causal implications, possible misclassification and reporting biases need to be considered.
Subclinical neurotoxicity of mercury vapor revealed by a multimodality evoked potential study of chloralkali workers
Authors: Chang Yang‐Chyuan , Yeh Ching‐Ying , Wang Jung‐Der
Published: April 2007

Pattern visual, brainstem auditory, and somatosensory evoked potential (EP) studies were performed on 26 chloralkali workers. The intensity of mercury vapor exposure in these workers was estimated from the individual working history. Mercury levels in blood, urine, and hair were determined with atomic absorption spectrometry. The EP findings were compared with those from individually matched normal subjects. In brainstem auditory and somatosensory EP studies, prolonged neural conduction times in the central nervous system (CNS) were found in workers exposed to mercury vapor. In the pattern visual EP study, mercury workers had higher interpeak amplitudes. Findings of this study suggested that chronic exposure to mercury vapor would affect the CNS functions. A multimodality EP study is a useful adjunct in evaluation of chronic mercury neurotoxicity, especially in an epidemiological study.
Does regression analysis of lung function data obtained from occupational epidemiologic studies lead to misleading inferences regarding the true effect of smoking?
Authors: Attfield Michael D. , Hodous Thomas K.
Published: April 2007

Exposure‐response studies of the relationship between ventilatory function and dust exposure in workers are often quantified using linear regression methods. In coal miners, this technique has indicated that average effects of smoking and moderate dust exposure are roughly equivalent. However, the validity of direct comparison of the average effects of smoking and dust exposure has been questioned, the argument being that smoking causes severe effects in a minority, but leaves the remainder largely unaffected. This hypothesis was studied by examining distributions of FEV1 in a group of working coal miners where mean effects associated with both smoking and dust exposure have been detected. Overall, the results suggest that comparison of average effects of smoking and dust exposure derived from linear regression analysis is valid and not misleading.
Mechanisms, chemical carcinogenesis, and risk assessment: Cell proliferation and cancer
Authors: Huff James
Published: April 2007

Mechanisms of carcinogenesis—and in particular chemically associated carcinogenicity—have attracted considerable scientific and public attention in the last decade. Much insight has been gained that will lead to more reasoned and better prevention, intervention, and treatment for the reduction of environmentally caused cancers. However, there seems to be an exaggerated tendency to embrace “mechanisms” not yet fully characterized, completely tested, unequivocally proven, and consensus accepted. More than 100 agents and exposure circumstances have been identified as causally or strongly associated with human cancers; for many the evidence was discovered first in experimental animals. More chemicals have been uncovered as carcinogenic in experimental animals, with as yet no or little available information in exposed human populations. Additional and expanded mechanistic and epidemiological studies should further elucidate the relevance of these agents to adverse human health effects, including cancers. Claims are being posed that certain chemical‐specific “mechanisms” in experimental systems are irrelevant to humans, and thus chemicals thought to be aberrantly carcinogenic in animals would present no cancer hazard to exposed humans. Nonetheless before undeniable proof becomes available, we must continue to proceed with sensitive and responsible caution. This commentary offers a central and personal view of one such mechanism: cell proliferation and cancer.
Respiratory protection and the risk of Mycobacterium tuberculosis infection
Authors: Nicas Mark
Published: April 2007

Tuberculosis (TB) can be transmitted to susceptible healthcare workers via inhalation of droplet nuclei carrying viable Mycobacterium tuberculosis bacilli. Several types of respiratory protective devices are compared with respect to efficacy against droplet nuclei penetration: surgical masks, disposable dust/mist particulate respirators (PRs), elastomeric halfmask respirators with high‐efficiency (HEPA) filters, and powered airpurifying respirators (PAPRs) with elastomeric halfmask facepieces and HEPA filters. It is estimated that these devices permit, respectively, 42%, 5.7%, 2%, and 0.39% penetration of droplet nuclei into the facepiece. More limited data for the disposable HEPA filtering‐facepiece respirator suggest that it would allow droplet nuclei penetration of 3% or less, similar to the value estimated for the elastomeric halfmask HEPA filter respirator. Because a respirator wearer's cumulative infection risk depends on the extent of droplet nuclei penetration, the cumulative risk will differ, given use of these different respirators. Hypothetical but realistic “low‐exposure” and “high‐exposure” scenarios are posed that involve, respectively, a 1.6% and a 6.4% annual risk of infection for healthcare workers. For the low‐exposure scenario, the 10‐year cumulative risks given no respirators versus surgical masks versus disposable dust/mist PRs versus elastomeric halfmask HEPA filter respirators versus HEPA filter PAPRs are, respectively, 15%, 6.7%, 0.94%, 0.33%, and .064%. For the high‐exposure scenario, the 10‐year cumulative risks for no respirator use versus use of the same four types of respirators are, respectively, 48%, 24%, 3.7%, 1.3%, and 0.26%. The use of disposable HEPA filtering‐facepiece respirator should permit cumulative risks close to those estimated for the elastomeric halfmask HEPA filter respirator. It is concluded that when an infectious TB patient undergoes a procedure that generates respiratory aerosols, and when droplet nuclei source control is inadequate, healthcare workers attending the patient may need to wear highly protective respirators, such as HEPA filter PAPRs.
Estimation of risk of developing bladder cancer among workers exposed to coal tar pitch volatiles in the primary aluminum industry
Authors: Tremblay Claude , Armstrong Ben , Thériault Gilles , Brodeur Jules
Published: April 2007

To confirm the relationship between exposure to coal tar pitch volatiles and bladder cancer among primary aluminum production workers, we carried out a case‐control study among blue‐collar workers who had worked more than 1 year between 1950‐1979 in a major plant using mostly the Soderberg process in the Province of Québec. Cases of bladder cancer (ICD code'l88) diagnosed between 1970‐1979 (n = 69) were mostly included in a previously reported study. To these were added cases diagnosed between 1980‐1988 (n = 69). Each case was matched to three controls on date of birth, date of hiring, and length of service at the company. Smoking habits were assessed from the medical records at the company. Benzene‐soluble matter (BSM) and benzo(a)pyrene (BaP) were used as indicators of environmental exposure to coal tar pitch volatiles in the workplace. The estimated risk for current smokers was 2.63 (95% C.I. 1.29‐5.37). Estimates of risk by occupational exposure were adjusted for smoking. Men who had worked in the Soderberg potrooms were at higher risk of developing the disease, the risk increasing with the time spent in these departments. Similarly, a strong association between risk and cumulative exposure to BSM or to BaP was observed. The risks associated with cumulative exposure to BSM (mg/m3 ‐years) and to Bap (μg/m3‐years) were described with mathematical models. Using a linear model (1 + bx) and lagging 10 years before the diagnosis. BaP cumulative exposure was a better indicator of risk than BSM cumulative exposure. The risk for each year of exposure to BaP at a concentration of 1 (xg/m3 increased by 1.7% (0.8%‐3.2%). Using the same model for BSM, a worker exposed to the current threshold limit value of 0.2 mg/m3 for 40 years will sustain a risk of 2.22 (1.56‐3.48). Comparison of risks according to different periods of diagnosis (1970‐1979 vs. 1980‐1988) did not reveal any significant temporal changes on risk estimates.
Biopersistence of cerium in the human respiratory tract and ultrastructural findings
Authors: Pairon Jean‐Claude , Roos Frédérique , Sébastien Patrick , Chamak Brigitte , Abd‐Alsamad Issam , Bernaudin Jean‐François , Bignon Jean , Brochard Patrick
Published: April 2007

For diagnostic purposes, mineralogical analysis was performed in bronchoalveolar la‐vage fluid and lung tissue from a 58‐year‐old patient previously exposed to asbestos and rare earth dusts. No significant retention of asbestos was demonstrated in lung tissue by light microscopy (asbestos bodies) or transmission electron microscopy analysis (un‐coated fibers). Particles containing rare earth (cerium, lanthanum) and phosphorus were identified in alveolar macrophages in bronchoalveolar lavage fluid, and cerium‐containing particles accounted for 70% of particles observed in the lung tissue. Ultrastructural analysis of lung tissue revealed the presence of particles containing cerium and phosphorus in interstitial macrophages and elastic fibers. These results suggest that rare earth is metabolized and should be considered as biopersistent in the human respiratory tract, since occupational inquiries revealed that exposure to cerium oxide abrasive powder had ceased at least 15 years earlier.
Respiratory symptoms and pulmonary function in flour processing workers in the baking industry
Authors: Shamssain Mohammad H.
Published: April 2007

Respiratory symptoms and ventilatory capacity were studied in 63 flour processing male bakery workers in Umtata, Transkei, Southern Africa. The controls were from a bottling plant in the same city. Both groups were black Africans from the Xhosa‐speaking population. The studied population was nonsmoking and no significant difference was noted in age, race, sex, or height between the groups. The exposed workers had significantly lower forced expiratory indices than the control group. Mean percent predicted values of forced expiratory volume in one second (FEV1), forced expiratory ratio (FEV1/FVC x 100), forced mid‐expiratory flow between 25% and 75% of FVC (FMF), forced expiratory flow between the first 200 ml and 1.200 ml of FVC (FEF 200‐1,200), and peak expiratory flow rate (PEF) were, respectively, 11.2%, 20.0%, 31.0%, 27.4%, and 36.1% lower in the exposed group compared with the controls. The prevalence of forced expiratory ratio less than 70% in the exposed group was 37% while in the controls it was 8%. The prevalence of PEF rate less than 5 l/s in the exposed group was 32% while in the controls it was 11%. The exposed workers reported a significantly higher prevalence of respiratory symptoms compared to the controls. The prevalence of nasal symptoms, phlegm, and cough in the exposed workers was 53.9%, 30.1%, and 25.4%, respectively. The present study demonstrated that exposure to flour dust in flour processing workers in the baking industry is associated with significantly lower pulmonary functions and a higher prevalence of respiratory symptoms, and that these workers show signs of airway obstruction, compared to workers not exposed to flour. Flour processing workers have a significant occupationally related respiratory impairment.
Silicosis in brazilian pit diggers: Relationship between dust exposure and radiologic findings
Authors: Holanda Márcia Alcǎntara , Holanda Marcelo Alcǎntara , Felismino Pedro Henrique , Pinheiro Valéria Góes Ferreira
Published: April 2007

The incidental diagnosis of two cases of silicosis at Messejana Hospital, Fortaleza, capital of Ceará state, triggered a field research conducted with the objective of investigating the incidence of silicosis in pit diggers in four towns in the Ibiapaba Mountain Range, at the state's northwestern area, northeastern Brazil. Out of a universe of 1,050 pit diggers in the area, 366 participated in the study; they were all males ranging in age between 16 and 76 years old (average 39 years). The excavation and the sickening process were described and a dust exposure index in pit diggers (DEIPD) was defined. The study sample indicated a rate of 121 (33.06%) silicotics and possibly silicotics. The radiologic findings were related to the DEIPD and indicated significant prevalence of disease. Furthermore, during the research period, from 1986 to 1989, 30 (34.9%) silicotics died of respiratory failure and wasting of body tissues. The data suggested that these men were afflicted with a severe occupational health problem, possibly scattered throughout a large area in northeastern Brazil, where manual pit excavations occur during the whole year and increase during drought periods.
Possible genotoxicity in low level benzene exposure
Authors: Karačić Višnja , Skender Ljiljana , Bosner‐Cucančić Branka , Bogadi‐Sare Ana
Published: April 2007

Structural chromosome aberrations and sister chromatid exchanges (SCEs) in peripheral blood were studied in female workers employed in the shoe‐making industry in two periods: 1987 (group I; N = 38) and 1992 (group II; N = 45). Only 11 of the workers were present in both groups and their results are presented both together and separately. Occupational exposure to benzene and toluene was confirmed through their determination in the working area, blood, and phenol in pre‐ and post‐shift urine. The results were compared with those from the control group (N = 35). Benzene in the working atmosphere was significantly higher in 1987 compared to 1992, but was always lower than the current Croatian permissible concentration of 50 mg m−3 (in the near future this value will be changed to 15 mg m−3). A statistically significant difference was also found in biological markers of benzene exposure between the two periods of the investigation. Increased absorption in the first period occurred because of intensified production in 1987, and this decreased significantly in 1992 because of the war in Croatia.

The cytogenetic study showed a significant increase in dicentric chromosomes in exposed groups I and II when compared to the control group. Statistically significant higher SCE frequencies were found in group I compared to the control group and also compared to group II. Between exposed group II and the controls no statistically significant difference in SCEs was found. Comparing the same 11 workers present in both periods the results showed no difference in chromosome aberrations between the two periods of examination. SCE frequencies were significantly higher in 1987 when greater benzene absorption occurred, confirmed by biomarkers of benzene exposure.

The presented results indicate that genotoxicity may occur in workers exposed to low levels of benzene in the shoe industry.