Showing papers in "American Journal of Industrial Medicine in 1994"
TL;DR: Video display terminal (VDT) operators in the editorial department of a large metropolitan newspaper participated in a study of day-to-day musculoskeletal symptoms, finding head rotation and relative keyboard height were significantly related to more severe pain and stiffness in the shoulders, neck, and upper back.
Abstract: Video display terminal (VDT) operators (n = 150) in the editorial department of a large metropolitan newspaper participated in a study of day-to-day musculoskeletal symptoms. Work posture related to the VDT workstation and psychosocial work factors were also investigated for their contributions to the severity of upper body pain, numbness, and stiffness using a representative subsample (n = 70). Self-report measures included Karasek's Job Content Instrument and the author-designed Work Interpersonal Relationships Inventory. Independent observations of work posture were performed using techniques similar to those reported by Sauter et al. [1991]. Pain during the last week was reported by 59% (n = 88) of the respondents, and 28% (n = 42) were categorized by symptom criteria potentially to have musculoskeletal disorders. More hours per day of VDT use and less decision latitude on the job were significant risk factors for potential musculoskeletal CTDs. Head rotation and relative keyboard height were significantly related to more severe pain and stiffness in the shoulders, neck, and upper back. Lower levels of co-worker support were associated with more severe hand and arm numbness. For both the region of the shoulders, neck, and upper back and the hand and arm region, however, the contributions of relative keyboard and seat back heights to symptom severity were modified by psychological workload, decision latitude, and employee relationship with the supervisor. Alternative explanations for these findings are discussed.
274 citations
Journal Article•
TL;DR: The data were poorly focused to address the carcinogenicity of bitumen fumes, as contrasted with tar-derived exposures, and the feasibility of a powerful multicenter cohort is currently being studied by the International Agency for Research on Cancer (IARC).
166 citations
TL;DR: In this article, the authors examined and combined the results of the epidemiologic studies conducted on asphalt workers and roofers in various countries, and examined the cancer risk separately in three broad job categories: 1) roofers (exposed to bitumen fumes and previously often to coal-tar fumes); 2) highway maintenance workers (HMWs), and 3) miscellaneous and unspecified bitumen/asphalt workers.
Abstract: Twenty epidemiologic studies have described cancer risk in asphalt workers and roofers in various countries. A current concern for these workers is the potential carcinogenicity posed by inhalation of bitumen fumes or dermal exposure to bitumens. Bitumens are chemically different from many carcinogenic coal-tar based materials. Both have been employed in road paving and waterproofing. We examined and combined the results of the epidemiologic studies conducted on asphalt workers and roofers. We examined the cancer risk separately in three broad job categories: 1) roofers (exposed to bitumen fumes and previously often to coal-tar fumes); 2) highway maintenance workers (HMWs) and road pavers (exposed to bitumen fumes as well as possibly coal-tar fumes previously); and 3) miscellaneous and unspecified bitumen/asphalt workers. In roofers, an increased risk was suggested for cancers of the lung (aggregated relative risk 1.8, 95% confidence interval 1.5-2.1), stomach (1.7, 1.1-2.5), nonmelanoma skin (4.0, 0.8-12), and leukemia (1.7, 0.9-2.9). Some of the excesses may be attributable to polycyclic aromatic hydrocarbons (PAH) from coal-tar products. The aggregated relative risks in road pavers and HMWs were consistently lower than in roofers for cancers of the lung (0.9, 0.8-1.0), stomach (1.1, 0.8-1.5), bladder (1.2, 0.7-1.8), skin (2.2, 1.2-3.7), and leukemias (1.3, 0.9-1.8). Their risk of skin cancer was significantly increased, based on one study. Miscellaneous and unspecified workers had a significant excess (1.5, 1.2-1.8) of lung cancer. The data were poorly focused to address the carcinogenicity of bitumen fumes, as contrasted with tar-derived exposures. For the prospect of shedding more light on the bitumen-cancer controversy, the feasibility of a powerful multicenter cohort is currently being studied by the International Agency for Research on Cancer (IARC).
164 citations
TL;DR: The authors conclude that prenatal lead exposure is unlikely to increase the risk of premature membrane rupture but does appear to increaseThe risk of preterm delivery, and whether prenatal lead Exposure decreases gestational age in terms of infants is unclear.
Abstract: Although the adverse effect on pregnancy outcomes at high levels of lead exposure in the workplace has been recognized for years, there is uncertainty regarding the impact of exposure at the lower community exposure levels commonly encountered today This review summarizes the epidemiologic literature and discusses pertinent methodologic issues and possible sources of interstudy variation The authors conclude that prenatal lead exposure is unlikely to increase the risk of premature membrane rupture but does appear to increase the risk of preterm delivery Whether prenatal lead exposure decreases gestational age in terms of infants is unclear Prenatal lead exposure also appears to be associated with reduced birth weight, but results vary in relation to study design and degree of control for confounding Adjustment for gestational age, a possible confounder of the birth weight-lead exposure association, did not yield clearer results
159 citations
TL;DR: Seasonal pattern of injury displayed a bimodal curve, one peak in spring, and a higher peak in early fall in September, and the most risky farm types were forestry and dairy.
Abstract: A population-based study of the occurrence of agricultural injuries during the previous year was conducted in a simple random sample of 1,000 farm operators in Alabama in 1991 The participation rate was 862% The cumulative 1-year incidence was 99% (95% CI = 77–121), based on the number of injuries, and 78% (95% CI = 58–98), based on the number of farmers injured Limbs were the body parts most frequently injured: fingers (107%), hands or wrists (107%), and legs (89%) The leading external causes were machinery (286%), falls (232%), and animals (125%) There was a higher injury frequency at the end of the week, with a Saturday peak Seasonal pattern of injury displayed a bimodal curve, one peak in spring, and a higher peak in early fall in September The most risky farm types were forestry and dairy The factors predictive of increased injury risk in multiple logistic regression included younger age, farm ownership, greater percent of working time spent on farming, more alcohol consumed, and prior residual injury The results provide some indications for formulating agricultural injury control programs and for future research © 1994 Wiley-Liss, Inc
129 citations
TL;DR: The excess risk for lung cancer among white males and females appeared to occur at cumulative exposures lower than those for black males, and possible reasons for the lesser lung cancer risk among black males include less smoking and differences in airborne fiber characteristics experienced by black males as a result of plant job placement patterns.
Abstract: Previous studies of mortality among white males employed in a Charleston, South Carolina asbestos textile plant using chrysotile demonstrated significant excess mortality due to asbestos-related disease and a steep exposure-response relationship for lung cancer. This cohort was further studied by adding 15 years of follow-up and including mortality among white female and black male workers. Nested case-control analyses were undertaken to further explore possible differences in lung cancer risk by textile operation as well as possible confounding by mineral oil exposures. Preliminary data for white males have been previously published. White males experienced statistically significant excess mortality due to lung cancer (standardized mortality ratio [SMR] = 2.30; confidence interval [CI] = 1.88-2.79), all causes (SMR = 1.48; CI = 1.38-158), all cancers (SMR = 1.50; CI = 1.29-1.72), diabetes mellitus (SMR = 2.05; CI = 1.18-3.33), heart disease (SMR = 1.41; CI = 1.26-1.58), cerebrovascular disease (SMR = 1.50; CI = 1.08-2.02), pneumoconiosis and other respiratory diseases (SMR = 4.10; CI = 3.10-5.31), and accidents (SMR = 1.49; CI = 1.15-1.91). Among white females, statistically significant excesses occurred for lung cancer (SMR = 2.75; CI = 2.06-3.61), all causes (SMR = 1.21; CI = 1.11-1.32), pneumoconiosis and other respiratory diseases (SMR = 2.40; CI = 1.53-3.60), and other respiratory cancers (SMR = 14.98; CI = 4.08-38.7). Among the total cohort of black males, the only statistically significant excess observed was for pneumoconiosis (SMR = 2.19; CI = 1.23-3.62). Based on historical exposure measurements at the plant, there was a positive exposure-response relationship for both lung cancer and pneumoconiosis. Data for the entire cohort demonstrate an increase in the lung cancer relative risk of 2-3% for each fiber/cc-year of cumulative chrysotile exposure. This relationship was more consistent for the white male workers. The excess risk for lung cancer among white males and females appeared to occur at cumulative exposures lower than those for black males. Possible reasons for the lesser lung cancer risk among black males include less smoking and differences in airborne fiber characteristics experienced by black males as a result of plant job placement patterns. The case-control analysis found employment in preparation and carding operations (where most of the black males worked) to be associated with a slightly reduced lung cancer risk, although not statistically significant, whereas spinning and twisting employment was associated with a statistically significant increased lung cancer risk compared to other plant operations.(ABSTRACT TRUNCATED AT 400 WORDS)
123 citations
TL;DR: Thirty-nine studies of male occupational exposure and risk of spontaneous abortion were examined, with the methods and results tabulated.
Abstract: The question of whether paternal exposures influence risk of spontaneous abortion is of great public interest, with the possibility supported by laboratory investigations. Thirty-nine studies of male occupational exposure and risk of spontaneous abortion were examined, with the methods and results tabulated. Many of those reports were limited by exposure data based on maternal report of the father's job title or by potentially inaccurate paternal reports of spontaneous abortion, though the quality of more recent studies is markedly enhanced. Mercury has been implicated most strongly based on recent studies that included quantitative exposure estimates; a number of studies showing associations for exposure to anesthetic gases. Suggestive associations have also been found inconsistently for exposure to lead, rubber manufacturing, selected solvents, and some pesticides. Further study is encouraged, but with more intensive effort to measure accurately both spontaneous abortion and occupational exposures. © 1994 Wiley-Liss, Inc.
121 citations
TL;DR: To improve the quality and specificity of data collected, a procedure called SCORE (Subject Corrected Occupational Report) is developed which provides the industrial hygienist with a cost efficient method to ask questions directly of respondents.
Abstract: The strength and credibility of evidence from occupational case-control studies largely depend on the validity and precision with which the work history is reported and the exposure is assessed We discuss the two steps which ultimately lead to an exposure decision The first step involves the exchange between the respondent and an interviewer The latter is usually naive to occupations and workplace exposures and, as such, is limited to asking generic and open-ended questions about the workplace Often, this type of information is too nonspecific to assess exposure In the second step, an expert reviews the information reported on each occupation and decides on exposure status without contacting either the interviewer or respondent Exposure assessment is not, therefore, integrated with data collection and, in fact, is usually not initiated until after all the interviews are completed As such, the exposure expert does not have an opportunity to resolve questions before making the exposure decision To improve the quality and specificity of data collected, we have developed over 40 sets of close-ended questions (branch questions) which are specific to defined occupations These branch questions, incorporated into a computer-assisted telephone interview, are asked if selected occupations or their synonyms are reported Second, to link the data collection process with the assessment process, we have developed a procedure called SCORE (Subject Corrected Occupational Report) which provides the industrial hygienist with a cost efficient method to ask questions directly of respondents Shortly after each interview is completed, a computerized version of the work history is reviewed by the industrial hygienist who develops questions when more information is needed Subsequently, respondents are mailed a form listing their reported work history along with the questions After two mailings, 73% of participants in a pilot study returned the SCORE form
96 citations
TL;DR: Personal exposure to airborne bacteria and symptoms were studied in sewage workers and an association between levels of total bacteria, rod-shaped bacteria, and symptoms, during and after work was found.
Abstract: Personal exposure to airborne bacteria and symptoms were studied in 24 sewage workers. An association between levels of total bacteria, rod-shaped bacteria, and symptoms, such as tiredness and headache, during and after work was found. © 1994 Wiley-Liss, Inc.
94 citations
TL;DR: The aim of this study was to identify occupational risk groups which might usefully be targeted for occupational asthma surveillance and control, using a community-based case-control approach.
Abstract: The aim of this study was to identify occupational risk groups which might usefully be targeted for occupational asthma surveillance and control, using a community-based case-control approach. Data on previous and current occupations held by subjects were analyzed for 787 adult patients with bronchial asthma and 1591 nonasthmatic patient controls, aged 20-54 years, belonging to the three major races (Chinese, Malays, and Indians) in five outpatient primary care polyclinics. Odds ratios (OR) and 95% confidence intervals (95% CI) of association were adjusted for sex, age, race, smoking, and clinical atopy. No associated risks of asthma were found for clerical or sales workers in general. Significantly reduced risks of association with asthma were found for professional, technical, administrative, and managerial occupations (OR, 0.62; 95% CI, 0.47-0.82). The associated risks of asthma were generally elevated for service workers (OR, 1.35; 95% CI, 1.04-1.74) and manufacturing production and related workers (OR, 1.49; 95% CI, 1.23-1.81). Among them, increased risks were observed for cleaners, particularly municipal cleaners and sweepers (OR, 1.91; 95% CI, 1.22-2.99), textile workers (OR, 5.83; 95% CI, 1.93-17.57), garment makers (OR, 1.61; 95% CI, 1.01-2.58), electrical and electronic production workers (OR, 1.36; 95% CI, 1.06-1.75), printers (OR, 2.24; 95% CI, 1.17-4.31), and construction/renovation workers (OR, 2.24; 95% CI, 1.30-3.85). The odds ratio of association of asthma with exposures in service and production-related occupations overall, relative to the “nonexposed” reference group of nonmanual professional/technical, administrative/managerial, clerical, and sales occupations, was estimated to be 1.72 (95% CI, 1.36-2.19); the estimated population attributable risk was 0.33 (95% CI, 0.22-0.44). © 1994 Wiley-Liss, Inc.
93 citations
TL;DR: It was concluded that the basic principles of good ergonomic design should be used to prevent or diminish the risk of musculoskeletal injury in the workplace.
Abstract: The California Department of Health Services evaluated carpal tunnel syndrome (CTS), a median nerve entrapment condition associated with forceful and repetitive wrist motion, among grocery store workers at a large California supermarket where a CTS cluster had been reported. Forceful and repetitive wrist motion was measured, in three exposure levels, through a job classification scheme based upon type of work tasks and average time per week spent performing these tasks. A medical questionnaire and measurements of median sensory nerve conduction were used to measure CTS. CTS prevalence was 23% based upon a sample of 56 participants drawn from a workforce of 69 employees. A relative risk of 8.3 (95% confidence interval 2.6-26.4) for a history of CTS-like symptoms between the high and low exposure level groups held up after adjustment for the potential confounders of age, sex, alcohol consumption, and high-risk medical history. It was concluded that the basic principles of good ergonomic design should be used to prevent or diminish the risk of musculoskeletal injury in the workplace.
TL;DR: The results suggest that previously reported cases of organophosphate-induced delayed polyneuropathy may represent only the worst disease in a spectrum of impairment, a sequela of exposure that may be much more common than previously thought.
Abstract: To evaluate chronic effects of acute organophosphate pesticide poisoning, quantitatively determined vibrotactile thresholds were measured as an index of peripheral neuropathy among agricultural workers in Nicaragua. Thirty-six male workers were evaluated between 10 and 34 months after hospitalization for acute organophosphate poisoning and compared to an age- and sex-matched community reference group. Vibrotactile thresholds were measured quantitatively in right and left index fingers and right and left great toes. Study subjects were stratified into three groups: 1) never poisoned; 2) poisoned with organophosphates other than methamidophos, agents which have not been reported to cause peripheral neuropathy; and 3) poisoned with methamidophos, a peripheral neurotoxin. For all digits, there was a statistically significant trend of increasing age- and height-adjusted thresholds across these three exposure categories. Over one fourth of patients previously poisoned with methamidophos we studied had abnormal vibrotactile thresholds. These results suggest that previously reported cases of organophosphate-induced delayed polyneuropathy may represent only the worst disease in a spectrum of impairment, a sequela of exposure that may be much more common than previously thought.
TL;DR: Risk of astrocytic brain tumors increased with probability and average intensity of exposure, and with duration of employment in jobs considered exposed to methylene chloride, but not with a cumulative exposure score.
Abstract: Chlorinated aliphatic hydrocarbons (CAHs) were evaluated as potential risk factors for astrocytic brain tumors. Job-exposure matrices for six individual CAHs and for the general class of organic solvents were applied to data from a case-control study of brain cancer among white men. The matrices indicated whether the CAHs were likely to have been used in each industry and occupation by decade (1920-1980), and provided estimates of probability and intensity of exposure for “exposed” industries and occupations. Cumulative exposure indices were calculated for each subject.
Associations of astrocytic brain cancer were observed with likely exposure to carbon tetrachloride, methylene chloride, tetrachloroethylene, and trichloroethylene, but were strongest for methylene chloride. Exposure to chloroform or methyl chloroform showed little indication of an association with brain cancer. Risk of astrocytic brain tumors increased with probability and average intensity of exposure, and with duration of employment in jobs considered exposed to methylene chloride, but not with a cumulative exposure score. These trends could not be explained by exposures to the other solvents.
TL;DR: 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.
Abstract: 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.
TL;DR: It is suggested that increased bone turnover accompanying thyrotoxicosis led to clinically significant lead poisoning in this patient, due to mobilization of accumulated bone lead stores acquired many years earlier.
Abstract: We describe a case of thyrotoxicosis accompanied by markedly elevated blood lead levels (initially 53 micrograms/dl) in a 37-year-old woman. No current source of lead exposure was found; the woman gave a history indicative of lead exposure as a child and as an adult 7 years previously, however. In addition, she was found to have markedly elevated bone lead levels, as measured by K-x-ray fluorescence (154 +/- 5 in the mid-tibia and 253 +/- 6 micrograms/g bone mineral in the patella), and an increased serum osteocalcin level (2.76 nmol/l), reflecting the increased bone turnover that often accompanies hyperthyroidism. During treatment with propylthiouracil, serial observations demonstrated a decline in serum osteocalcin that paralleled a decline in blood lead levels. Bone lead levels did not change appreciably. The patient also continued to have lingering neuropsychological symptoms consistent with chronic lead effects. We suggest that increased bone turnover accompanying thyrotoxicosis led to clinically significant lead poisoning in this patient, due to mobilization of accumulated bone lead stores acquired many years earlier. This phenomenon raises the general issue of more subtle forms of lead exposure from increased bone turnover states (e.g., osteoporosis).
TL;DR: Fire fighters working with fire fighting methods used in Sweden from the beginning of this century onwards are not systematically exposed to known stomach or brain carcinogens, and the results need confirmation in further studies with extensive exposure evaluations.
Abstract: Fire fighters are exposed to irritating, asphyxiating, and toxic gases and aerosols, to psychological stress, and to physically demanding work. Due to differences in fire fighting techniques, exposure conditions for fire fighters differ among different countries. The purpose of this investigation was to study cancer incidence and mortality in fire fighters who have been working with fire fighting methods used in Sweden from the beginning of this century onwards. All male fire fighters employed for at least 1 year in the City of Stockholm during 1931-1983 were traced, and an index of the number of fires fought was calculated for each individual. The mortality during 1951-1986 (among 1, 116 fire fighters) was lower than expected (SMR = 82; 95% confidence interval 72-91) compared with local mortality rates, with a low mortality in circulatory diseases, obstructive lung diseases, violent deaths, and suicides. The cancer incidence in 1958-1986 was equal to the expected (SMR = 100; 95% confidence interval 83-119). However, an excess of stomach cancer (18 observed vs. 9.37 expected; SMR = 192, 95% CI 114-304) was observed. There was also a tendency for higher incidence and mortality in stomach and brain cancer with increasing number of fires. There were four deaths from brain cancer compared to 0.8 expected (SMR = 496; 95% CI 135-1270) in the highest exposure category. Fire fighters are, however, not systematically exposed to known stomach or brain carcinogens, and the results need confirmation in further studies with extensive exposure evaluations.
TL;DR: The data indicate that the adverse effect of arsenic on the peripheral nerves is dependent on long-term exposure rather than on short-term fluctuations in exposure levels.
Abstract: In a group of 43 smelter workers exposed to inorganic arsenic dust for 13-45 years, nerve conduction velocities (NCVs) were significantly lower in two peripheral nerves as compared with matching referents. With multivariate data analysis, a significant negative correlation was found between cumulative absorption of arsenic and NCV in four examined nerves and the sural amplitude. Clinical symptoms of neuropathy and other symptoms related to arsenic exposure were moderate, though the difference between the groups was significant. The mean total absorption of arsenic was calculated to be less than 5 g, and the maximal absorption about 20 g. These data indicate that the adverse effect of arsenic on the peripheral nerves is dependent on long-term exposure rather than on short-term fluctuations in exposure levels. © 1994 Wiley-Liss, Inc.
TL;DR: The development of a weighted multiple regression model is presented for estimation of exposure levels to ethylene oxide (ETO) for inclusion in a cohort mortality study of workers in the sterilization industry.
Abstract: Since direct measures of individual exposure seldom exist for the entire period of an occupational mortality study, retrospective exposure estimates are necessary. This is often done in a subjective manner involving a consensus of opinion from a panel of epidemiologists and industrial hygienists. An alternative method utilizing a statistical model provides a more objective procedure for retrospective exposure assessment. The development of a weighted multiple regression model is presented for estimation of exposure levels to ethylene oxide (ETO) for inclusion in a cohort mortality study of workers in the sterilization industry. Three steps in development of the model are described: (1) data acquisition and assessment, (2) model building, and (3) evaluation of the model. The final model explained a remarkable 85% of the variability in 205 average measurements of ETO levels. Exposure factors included in the model were exposure category, product type, size of the sterilization unit, selected engineering controls, days after sterilization, and calendar year. The model was evaluated in two ways: against a set of measurement data not used to develop the model and a panel of 11 industrial hygienists representing the sterilization industry. The model predicted ETO exposures within 1.1 ppm of the validation data set with a standard deviation of 3.7 ppm. The arithmetic and geometric means of the 46 measurements in the validation data set were 4.6 and 2.2 ppm, respectively. The model also outperformed the panel of industrial hygienists relative to the validation data in terms of both bias and precision.
TL;DR: Assessing possible lung cancer risks in relation with cobalt exposure showed that smoking alone does not account for these lung cancer excesses, yet, because of the small numbers involved, no firm conclusion should be drawn from this study.
Abstract: A cohort mortality study was carried out among workers of a plant producing hard metals using cobalt as a binder. This study was aimed at assessing possible lung cancer risks in relation with cobalt exposure. Seven hundred nine male workers with at least 1 year of employment were included in the cohort and followed for mortality from 1956 to 1989. Job histories were provided by the administration of the plant, whereas smoking habits were collected from medical records and by interview. The causes of deaths were ascertained from hospital and general practitioner records. The observed numbers of deaths (obs) were compared with the expected based on national rates with adjustment for age, sex, and calendar time (standardized mortality ratio; SMR). The overall mortality did not differ from that expected (obs = 75, SMR = 1.05), whereas mortality due to lung cancer was in significant excess (obs = 10, SMR = 2.13). This excess was higher among workers employed in the areas with the highest exposure (obs = 6, SMR = 5.03). No trend was observed, however, with duration of employment or time since first employment. Smoking data were available for 81% of the workers and 69% of the deceased and showed that smoking alone does not account for these lung cancer excesses, yet, because of the small numbers involved, no firm conclusion should be drawn from this study.
TL;DR: The results of this study are in concordance with other studies that indicate acute effects on lung function and elevated prevalences of respiratory symptoms during work caused by exposure to grain dust.
Abstract: Reported respiratory and related symptoms during work were compared between 265 exposed animal feed workers and a control group consisting of 175 external controls and nonexposed workers in the animal feed industry. Symptoms indicating respiratory and nasal irritation were significantly increased in the animal feed workers. Prevalences ranged from 9% (cough) to 21% (sneezing). Reported cough after work was also significantly increased. In 119 workers, a total of 457 across-shift spirometric lung function changes were measured. Almost all lung function variables showed a decrease during the work shift, as could be expected since the circadian rhythm is in a downward phase during the measurement period (2 p.m.-10 p.m.). When the workers were grouped into dust and endotoxin exposure categories according to their job titles, and exposure-response trend was seen for maximum mid-expiratory flow (MMEF) and maximum expiratory flow rate at 50% of vital capacity (MEF50). The effect of endotoxin was stronger than that of dust, both in magnitude and significance. For the same lung function variables and for forced expiratory volume in 1 second (FEV1) and MEF25, a significant across-week change was also detected. The results of this study are in concordance with other studies that indicate acute effects on lung function and elevated prevalences of respiratory symptoms during work caused by exposure to grain dust.
TL;DR: The results strongly support the necessity for designing and testing special local exhaust-ventilated worktables with necessary flexibility for dissecting operations with formaldehyde exposure, acute pulmonary response, and exposure control options.
Abstract: Formaldehyde exposure, acute pulmonary response, and exposure control options were evaluated in a group of 34 workers in a gross anatomy laboratory. Time-weighted average (TWA) exposure to formaldehyde ranged from 0.07-2.94 parts per million (ppm) during dissecting operations. More than 94% were exposed to formaldehyde in excess of the ceiling value of 0.3 ppm recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The eight-hour TWA exposure of 31.7% of the subjects exceeded the action level of 0.5 ppm set by the Occupational Safety and Health Administration (OSHA). Reported symptoms included irritation of eye (88%), nose (74%), throat (29%), and airways (21%). Forced vital capacity (FVC) and forced expiratory volume in 3 seconds (FEV3) decreased, and FEV1/FVC increased during the exposure. The changes of FEV3 were statistically different from those of the controls. The results strongly support the necessity for designing and testing special local exhaust-ventilated worktables with necessary flexibility for dissecting operations.
TL;DR: This work recommends that standardized exposure assessment methods be used to derive quantitative exposure estimates and identifies sources of variation inherent to the assessment process, including quality of the information reported on the job, industry, activities, and materials; the industrial hygienist's familiarity with the reported job/industry; the probability that the job/ industry was exposed; and variability in workplace characteristics.
Abstract: Obtaining valid and reliable quantitative exposure estimates is a significant challenge in community-based case-control studies in part, because industrial hygiene monitoring data are usually not available and detailed information on the job and work environment is usually not systematically obtained or assessed. To improve the quality and credibility of disease risk information obtained from occupational case-control studies, we recommend that standardized exposure assessment methods be used to derive quantitative exposure estimates. We identify sources of variation inherent to the assessment process, including: the quality of the information reported on the job, industry, activities, and materials; the industrial hygienist's familiarity with the reported job/industry; the probability that the job/industry was exposed, which depends on plant preferences for particular substances, on process technology, and on customer specifications; and variability in workplace characteristics. To improve the reliability of estimating job-related exposures both within and between studies, we recommend that the epidemiologic analyses be conducted with and without data rated to be of poor quality; that contact be made with experts when the study industrial hygienist is unfamiliar with the manufacturing process in question; that existing data bases be used to estimate the probability of exposure; that a data base be developed that describes manufacturing processes; and that explicit criteria based on industrial hygiene principles be used to evaluate workplace characteristics. In addition, a procedure is described for deriving quantitative exposure estimates by using a reference scale of frequently monitored jobs with their associated mean exposure levels. Areas of research are identified to improve exposure assessment in community-based case-control studies.
TL;DR: In this population, no association was seen between any outcome and age, gender, marital status, or baseline wage, and duration of disability was not significantly related to preoperative severity of OCTS or to more specific case criteria for this condition.
Abstract: All cases of occupational carpal tunnel syndrome (OCTS) who received surgery for this condition in the Washington State workers' compensation system were identified using claim and physician billing databases. One hundred ninety-one incident surgical cases were identified between July 1, 1987 and December 31, 1987, and were followed up a mean of 3 years postoperatively for clinical, disability, and return to work outcomes. Medical record and claim file review was required for clinical and employment information. The mean age of all patients was 36.6 years, 48% were female, and 40% received bilateral surgery. The mean time from claim filing to surgery was 187 days. Ninety-eight percent of cases met the National Institute for Occupational Safety and Health (NIOSH) case definition for OCTS. Relief of pain was complete or modest in 86% (124/145) and only 14% of cases reported no improvement in symptoms. Mean duration of disability (time loss) postoperatively was nearly 4 months, and 8% of cases exceeded 1 year of time loss. The majority of cases returned to their same job (67%) or to a different job (15%). Workers in high risk occupations were less likely to return to the same job after CTS surgery compared to those in lower risk occupations (61% vs. 75%, p = 0.08).
In this population, no association was seen between any outcome and age, gender, marital status, or baseline wage. Duration of disability was not significantly related to preoperative severity of OCTS or to more specific case criteria for this condition. These findings suggest that disability following surgery for OCTS may be related to other medical, psychosocial, administrative, legal, or work-related factors not evaluated in this study. © 1994 Wiley-Liss, Inc.
TL;DR: Early findings of high mortality among seafarers were confirmed, and negative selection into the occupation, occupational environmental factors, and lack of health and safety promotion programs and education could be causes of the high mortality.
Abstract: A retrospective cohort study was performed to analyze the mortality patterns of Danish merchant seamen in the period 1970-1985 The population census in 1970 in Denmark was the source of information on individual occupation, age, and marital status All men aged 20-64 years and economically active in 1970 were included Computerized linkage with the Danish Mortality Register gave information about the deceased persons' date and cause of death An increased overall mortality among all groups of seamen was found, being highest for deck and engine crew members The overall mortality was strongly dependent on age and marital status The highest mortality rate ratios (MRR) were found among young seamen and unmarried seamen MRRs of 190 and 247 for cancer of the respiratory system were found among engine officers and crew The MRRs for accidents and suicide were increased for all seamen, and were highest for crew members, among whom the MRR from accidents was stable within age groups but fell for suicide with increasing age The same pattern was found with cirrhosis of the liver, although this was positively associated with increasing age Excess mortality from ischemic heart disease was only found among engine crew (MRR = 143) This study confirms earlier findings of high mortality among seafarers Negative selection into the occupation, occupational environmental factors, and lack of health and safety promotion programs and education could be causes of the high mortality
TL;DR: This study is consistent with others in demonstrating that fire fighters experience increased risk of death from cancer of the brain, and in suggesting increased risk for various other causes of death.
Abstract: Fire fighters are exposed to substances which are recognized or suspected causal agents in cancer or heart disease. The purpose of this study was to determine whether or not fire fighters experience increased risk for any specific cause of death. A retrospective cohort study was conducted, with 5,995 subjects recruited from all six fire departments within Metropolitan Toronto. The mortality experience of the cohort was ascertained through computerized record linkage and compared to that of the male Ontario population specific to cause, age, and calendar period from 1950 through 1989. Average duration of follow-up was 21 years, and there were 777 deaths among the 5,414 males included in the analysis, giving an all-cause standardized mortality ratio of 95 (95% confidence interval: 88-102). Three specific causes of death exhibit statistically significant excesses (brain tumors, "other" malignant neoplasms, and aortic aneurysms). There are also slight increases in risk for some other sites of cancer, and for various diseases of the respiratory, circulatory, and digestive systems. This study is consistent with others in demonstrating that fire fighters experience increased risk of death from cancer of the brain, and in suggesting increased risk for various other causes of death. Language: en
TL;DR: Past machining fluid levels prior to 1970 were generally two to five times higher than subsequent measurements, and changes in exposure levels generally corresponded with reported changes in plant environments such as installation of enclosures and local exhaust ventilation on machines.
Abstract: A retrospective exposure assessment study in the automotive parts industry conducted in conjunction with a cancer mortality and respiratory morbidity study [Kennedy et al. (1989): Am J Ind Med 15:627-641; Eisen et al. (1992): Am J Ind Med 22:809-824; Tolbert et al. (1992): Scand J Work Environ Health 18:351-360] describes exposure to different types of machining fluids and selected components that may contribute to the conditions investigated. A dataset of 394 industrial hygiene measurements made between 1958 and 1987 was used to estimate past machining fluid levels using a linear statistical model. The effects of different plants, machining fluid types, machining operations, and time periods were examined in the model. Separate analyses examined the effects of different sampling and analysis methods and other measurement variables. Machining fluid levels prior to 1970 were generally two to five times higher than subsequent measurements. The arithmetic mean exposure of all measurements taken before 1970 was 5.42 mg/m3. Arithmetic means for different subgroups ranged from 0.59 to 20.28 mg/m3, depending upon plant, machining fluid, and operation. The arithmetic mean exposure after 1980 was 1.82 mg/m3 with subgroups ranging from 0.45 to 2.79 mg/m3. Changes in exposure levels generally corresponded with reported changes in plant environments such as installation of enclosures and local exhaust ventilation on machines.
TL;DR: Comparing and contrasting four different data sources found occupational diseases are a significant and under-estimated cause of morbidity and mortality in Canada.
Abstract: Objective: To estimate the extent of occupational disease morbidity and mortality in Canada by comparing and contrasting four different data sources. Data Sources: 1) Canadian National Workers' Compensation Boards Statistics, 2) U.S. Bureau of Labor Statistics adjusted to Canadian Workforce, 3) California Physician's First Reports adjusted to the Canadian Workforce, and 4) proportionate model of overall disease incidence obtained through literature review. Main Findings: Each data source was limited in its ability to provide a true estimate of the extent of morbidity and mortality due to occupational disease in Canada. Collectively, an estimate of between 77,900 and 112,000 new cases of occupational diseases and 2,381 to 6,010 occupational disease deaths were obtained. Conclusions: Occupational diseases are a significant and underestimated cause of morbidity and mortality in Canada. © 1994 Wiley-Liss, Inc.
TL;DR: There was a suggestion of increased risk of impaired visuospatial organization and a tendency to a decline in psychomotor tempo in the potroom workers, and this may be related to long-term occupational exposure in the Potroom, and further to chronic low-dose exposure to aluminum.
Abstract: A cross-sectional study was conducted at a Norwegian primary aluminum plant. All workers aged 61-66 years were offered early retirement benefits. Among the workers, 47 met the study criteria and 38 (81%), comprising 14 potroom workers, 8 foundry workers, and 16 controls, volunteered to participate. They were tested with a neuropsychological test battery. Workers in potrooms with Soderberg electrolytic cells were found to show signs of impairment of the nervous system. A test for tremor discriminated significantly between the potroom group and the controls. There was a suggestion of increased risk of impaired visuospatial organization and a tendency to a decline in psychomotor tempo in the potroom workers. We suggest that the above findings may be related to long-term occupational exposure in the potroom, and further to chronic low-dose exposure to aluminum.
TL;DR: A registry-based case-control study among men aged 20-64 years with known occupation who were diagnosed with cancer in Los Angeles County between 1972 and 1990, consistent with findings from studies based on job title alone that electrical workers may be at slightly increased risk of leukemia.
Abstract: To address the hypotheses that electrical workers are exposed to higher magnetic fields and are at higher risk of leukemia than nonelectrical workers, we performed a registry-based case-control study among men aged 20-64 years with known occupation who were diagnosed with cancer in Los Angeles County between 1972 and 1990. Controls were men with cancers other than those of the central nervous system or leukemia. Magnetic field measurements on workers in each electrical occupation and in a random sample of occupations presumed to be nonelectrical were used to estimate magnetic field exposures for each occupation. Among men in electrical occupations, 121 leukemias were diagnosed. With the exception of electrical engineers, magnetic field exposures were higher among workers in electrical occupations than in nonelectrical occupations. A weakly positive trend in leukemia risk across average occupational magnetic field exposure was observed (odds ratio [OR] per 10 milligauss increase in average magnetic field = 1.2, 95% confidence interval [CI] 1.0-1.5). A slightly stronger association was observed for chronic myloid leukemia, although only 28 cases occurred among electrical workers (OR 10 milligauss increase = 1.6, 95% CI = 1.2-2.0). The results were not materially altered by adjustment for exposure to several agents known or suspected to cause leukemia. Although not conclusive, these results are consistent with findings from studies based on job title alone that electrical workers may be at slightly increased risk of leukemia.
TL;DR: The approach quantified historical exposure to benzene in a multi-industry, multicenter cohort, involving 672 factories in 12 cities in China, using a retrospective exposure assessment method used in a follow-up mortality study of workers exposed to Benzene.
Abstract: This report describes a retrospective exposure assessment method used in a follow-up mortality study of workers exposed to benzene. The approach quantified historical exposure to benzene in a multi-industry, multicenter cohort, involving 672 factories in 12 cities in China. Historical exposure data were collected to obtain exposure information related to 1,427 work units (departments) and 3,179 unique job titles from benzene-producing or -using factories in which written records and other data sources were evaluated. The basic unit for exposure assessment was a factory/work unit/job title combination which was considered separately during each of seven calendar-year time periods between 1949 and 1987 for a total of 18,435 exposure assignments. Historical information collected to estimate exposure included benzene monitoring data; lists of raw materials and factory products, and the percentage of benzene in each; the total amount and dates of use of benzene or benzene-containing materials; use of engineering controls and personal protective equipment; and other available exposure information. Overall, 38% (ranging from 3% for the earliest periods to 67% for the last period) of the estimates were based primarily on benzene monitoring data. In the absence of job-specific benzene monitoring data for a given calendar period, measurement results or exposure estimates for similar jobs and/or other calendar periods were used in conjunction with other exposure information to derive estimates. Estimated exposure levels are presented by industries and occupations. The highest average exposures during 1949-1987 were observed for the rubber and plastic industry (30.7 ppm), and for rubber glue applicators (52.6 ppm).