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ObjectivesTo assess if improvement of working conditions related to heat stress was associated with improved kidney health outcomes among sugarcane harvest workers in Chichigalpa, Nicaragua, a region heavily affected by the epidemic of chronic kidney disease of non-traditional origin.MethodsBased on our findings during the 2017–2018 harvest (harvest 1), recommendations that enhanced the rest schedule and improved access to hydration and shade were given before the 2018–2019 harvest (harvest 2). Actual work conditions during harvest 2 were then observed. Serum creatinine (SCr) was measured before and at end-harvest, and cross-harvest changes in estimated glomerular filtration rate (eGFR) and incident kidney injury (IKI, ie, SCr increase by ≥0.30 mg/dL or ≥1.5 times the baseline value) were compared between harvest 1 and harvest 2 for three jobs with different physical workloads using regression modelling. Workers who left during harvest were contacted at home, to address the healthy worker selection effect.ResultsIn burned cane cutters, mean cross-harvest eGFR decreased 6 mL/min/1.73 m2 (95% CI 2 to 9 mL/min/1.73 m2) less and IKI was 70% (95% CI 90% to 50%) lower in harvest 2 as compared with harvest 1 data. No such improvements were seen among seed cutters groups with less successful intervention implementation.ConclusionKidney injury risk was again elevated in workers with strenuous jobs. The results support further efforts to prevent kidney injury among sugarcane workers, and other heat-stressed workers, by improving access to water, rest and shade. The distinction between design and implementation of such interventions should be recognised.

ObjectivesTo examine the association between workload and kidney injury in a fieldworker cohort with different levels of physically demanding work over a sugarcane harvest, and to assess whether the existing heat prevention efforts at a leading occupational safety and health programme are sufficient to mitigate kidney injury.MethodsBiological and questionnaire data were collected before (n=545) and at the end (n=427) of harvest among field support staff (low workload), drip irrigation workers (moderate), seed cutters (high) and burned sugarcane cutters (very high). Dropouts were contacted (87%) and reported the reason for leaving work. Cross-harvest incident kidney injury (IKI) was defined as serum creatinine increase ≥0.30 mg/dL or ≥1.5 times the baseline value, or among dropouts reporting kidney injury leading to leaving work.ResultsMean cross-harvest estimated glomerular filtration rate change was significantly associated with workload, increasing from 0 mL/min/1.73 m2 in the low-moderate category to −5 mL/min/1.73 m2 in the high and −9 mL/min/1.73 m2 in the very high workload group. A similar pattern occurred with IKI, where low-moderate workload had 2% compared with 27% in the very high workload category. A healthy worker selection effect was detected, with 32% of dropouts reporting kidney injury. Fever and C reactive protein elevation were associated with kidney injury.ConclusionsWorkers considered to have the highest workload had more cross-harvest kidney damage than workers with less workload. Work practices preventing heat stress should be strengthened and their role in preventing kidney damage examined further. Future occupational studies on chronic kidney disease of unknown aetiology should account for a healthy worker effect by pursuing those lost to follow-up.

A single paragraph of about 200 words maximum. For research articles, abstracts should give a pertinent overview of the work. We strongly encourage authors to use the following style of structured abstracts, but without headings: (1) Introduction: Place the question addressed in a broad context and highlight the purpose of the study, (2) Methods: Describe briefly the main methods or treatments applied, (3) Results: Summarize the article&rsquo, s main findings, and (4) Conclusions: Indicate the main conclusions or interpretations. The abstract should be an objective representation of the article, it must not contain results which are not presented and substantiated in the main text and should not exaggerate the main conclusions.

OBJECTIVE: The aim of this study was to assess the potential to reduce kidney function damage during the implementation of a water, rest, shade (WRS) and efficiency intervention program among sugarcane workers. METHODS: A WRS intervention program adapted from the US Occupational Safety and Health Administration (OSHA) coupled with an efficiency program began two months into the 5-month harvest. One of the two groups of workers studied was provided with portable water reservoirs, mobile shaded tents, and scheduled rest periods. Health data (anthropometric and questionnaires), blood, and urine were collected at baseline and at three subsequent times over the course of the harvest. Daily wet bulb globe temperatures (WBGT) were recorded. RESULTS: Across a working day there were changes in biomarkers indicating dehydration (urine osmolality) and serum albumin and reduced estimated glomerular filtration rate (eGFR). Cross-shift eGFR decrease was present in both groups; -10.5 mL/min/1.73m2 [95% confidence interval (95% CI) -11.8– -9.1], but smaller for the intervention group after receiving the program. Decreased eGFR over the 5-month harvest was seen in both groups: in the one receiving the intervention -3.4 mL/min/1.73m^2 (95% CI -5.5– -1.3) and in the other -5.3 (95% CI -7.9– -2.7). The decrease appeared to halt after the introduction of the intervention in the group receiving the program. CONCLUSION: A WRS and efficiency intervention program was successfully introduced for workers in sugarcane fields and appears to reduce the impact of heat stress on acute and over-harvest biomarkers of kidney function. Further research is needed to determine whether biomarker changes predict reduced risk of chronic kidney disease in this type of work.

The ways historians assemble primary material from which to learn how industry has failed to protect workers and the environment is changing dramatically. Increasingly, historians focus concern on the evolution of the internet and the demise of paper records. The authors of "Monsanto, PCBs," and the Creation of a "World-Wide Ecological Problem" (2018) are also founders of ToxicDocs.org. This web-based resource provides an entirely new degree of transparency. Readers of their article may look at any document they cite by clicking on the reference. Those with or without expertise in science can now judge these authors' analysis, and much more: entertain new lines of inquiry, ask new questions, obtain new insights, and publish well-documented pieces that offer new knowledge and insight to enrich our understanding, not only of the PCB story, but also industry's general behavior when using or marketing toxic substances.

Background Health and injury surveillance data of the highest achievable quality are needed in order to appropriately allocate scarce resources at the local and national levels. Methods This is the first reported surveillance study of injury using a complete community sample in Viet Nam. Workplaces in Xuan Tien Commune most likely to benefit from intervention were identified and ranked by the magnitude of the problem (or highest injury count), the risk (highest incidence rates) and the burden (the effect of injuries on the livelihoods of workers). Results 591 injuries occurring in the month prior to survey administration were recalled, which satisfied the injury case criteria of this study (the annualised incidence rate (IR) was 681 per 1000 residents). 482 were attributed to work activities (82%), yielding an annualised IR of 1001/1000 full time employee equivalents (FTE). The highest number of injuries occurred in the manufacturing sector (n=299), followed by agriculture with far fewer injuries (n=70). The highest rate of injury was in the transport, storage and communications sector (annualised IR 1583/1000 FTE), followed by manufacturing (1235/1000 FTE) and agriculture (844/1000 FTE). Conclusion This study identified patterns of risk which, because data collection reflected work culture, are believed to be more reliable than those from previous studies. Interventions in the manufacture of machinery and equipment sector (the largest industry in the commune) would have the most impact in reducing occupational injuries. Despite the trend towards manufacturing, agriculture is still a high priority with a continuing substantial impact.

There is an epidemic of chronic kidney disease (CKD) of unknown etiology in Central American workers.To investigate changes and job-specific differences in kidney function over a 6-month sugarcane harvest season, explore the potential role of hydration, and measure proteinuria.We recruited 284 Nicaraguan sugarcane workers performing seven distinct tasks. We measured urine albumin and serum creatinine and estimated glomerular filtration rate (eGFR).eGFR varied by job and decreased during the harvest in seed cutters (-8·6 ml/min/1·73 m(2)), irrigators (-7·4 ml/min/1·73 m(2)), and cane cutters (-5·0 ml/min/1·73 m(2)), as compared to factory workers. The number of years employed at the company was negatively associated with eGFR. Fewer than 5% of workers had albumin-to-creatinine ratio (ACR)30 mg/g.The decline in kidney function during the harvest and the differences by job category and employment duration provide evidence that one or more risk factors of CKD are occupational.

Background: Exposure to metalworking fluids has been previously associated with prostate cancer mortality in a cohort of autoworkers. Our objective was to further explore this finding in a study of prostate cancer incidence in the same cohort, with reduced misclassification of outcome. Methods: We conducted a nested case-control study in the General Motors cohort of autoworkers. Incident cases of prostate cancer (n = 872) were identified via the Michigan Cancer Registry from 1985 through 2000. Controls were selected using incidence-density sampling with 5:1 ratio. Using cumulative exposure (mg/m 3 -years) as the dose metric, we first examined varying lengths of lags (0-25 years). Then, we evaluated consecutive windows of exposure: 25 or more years before risk age, and fewer than 25 years. We used penalized splines to model the relative risk as a smooth function of exposure, and adjusted for race and calendar year of diagnosis in a Cox model. Results: Risk of prostate cancer increased with exposure to soluble and straight fluids 25 years or more before risk age but not with exposure in the last 25 years. The relationship with soluble fluids was piecewise linear, with a small increase in risk at lower exposures followed by a steeper rise. By contrast, the relationship with straight fluids was linear, with a relative risk of 1.12 per 10 mg/m 3 -years of exposure (95% confidence interval = 1.04-1.20). Conclusions: Exposure to oil-based fluids, soluble and straight, is modestly associated with prostate cancer risk among autoworkers, with a latency period of at least 25 years.

Objective Results are presented for a registry-based study of hepatobiliary cancer (liver and biliary tract) nested in a cohort of workers from three automobile manufacturing plants with potential exposure to metalworking fluids. Methods Altogether 63 cases of hepatobiliary cancer were identified from the cohort by the Michigan cancer registries. Each case was matched to 10 controls. Odds ratios (OR) were estimated in conditional logistic regression models for lifetime exposure to straight, soluble, and synthetic metalworking fluid and fluid components. Results Overall, hepatobiliary cancer was not associated with exposure to metalworking fluids. However, when the cases were stratified into liver cancer (N=39) and biliary tract cancer (N=24) the risk was nonhomogeneous across the two categories. While liver cancer was not associated with exposure to metalworking fluids, the results suggested a possible excess risk of biliary tract cancer with more than 1.0 mg/m 3 -years of exposure to straight metalworking fluids [OR 2.7, 95% confidence interval (95% CI) 0.9–7.6], as well as any exposure to chlorinated paraffins (OR 3.9, 95% CI 0.9–17). When exposures to straight metalworking fluids were separated into 10-year exposure periods, the odds ratio increased to 6.24 (95% CI 1.62–24.16) for exposures occurring >20 years prior to the risk date. Conclusions There is limited evidence that exposure to straight metalworking fluids is associated with biliary tract cancer. The small numbers of cases of these rare cancers were reflected in the wide confidence intervals, and these findings need to be examined further in other exposed populations.

Upper extremity musculoskeletal disorders (UEMSDs) comprise a large proportion of work-related illnesses in the USA. Physical risk factors including manual force and segmental vibration have been associated with UEMSDs. Reduced sensitivity to vibration in the fingertips (a function of nerve integrity) has been found in those exposed to segmental vibration, to hand force, and in office workers. The objective of this study was to determine whether an association exists between digital vibration thresholds (VTs) and exposure to ergonomic stressors in automobile manufacturing. Interviews and physical examinations were conducted in a cross-sectional survey of workers (n = 1174). In multivariable robust regression modelling, associations with workers' estimates of ergonomic stressors stratified on tool use were determined. VTs were separately associated with hand force, vibration as felt through the floor (whole body vibration), and with an index of multiple exposures in both tool users and non-tool users. Additional associations with contact stress and awkward upper extremity postures were found in tool users. Segmental vibration was not associated with VTs. Further epidemiologic and laboratory studies are needed to confirm the associations found. The association with self-reported whole body vibration exposure suggests a possible sympathetic nervous system effect, which remains to be explored.

Background Metalworking fluids (MWF) are used for lubrication during metal manufacturing. Previous studies have observed increased risks of several cancers among MWF-exposed workers. We hypothesized that MWF may be associated with risk of breast cancer because they can contain carcinogenic or endocrine-disrupting chemicals. Methods We conducted a case-control study nested in a cohort of 4,680 female automobile workers employed for at least 3 years between 1/1/41 and 1/1/85, with follow-up through 1994. Cases were identified using the National Death Index (NDI), Michigan cancer registries, and company records. Detailed quantitative MWF exposure data were available for each subject, although data on known breast cancer risk factors were not. Results Ninety-nine cases of breast cancer and 626 matched controls were identified. There was a weak positive association between lifetime cumulative exposure to soluble MWF and breast cancer risk, but no evidence of association with either straight or synthetic fluids. When exposure was divided into time-windows, the association was strongest for soluble MWF in the decade preceding diagnosis. Controlling for earlier exposures, there was an odds ratio of 1.18 (95% CI = 1.02–1.35) per mg/m3-year of cumulative exposure to soluble MWF in this 10-year period. Conclusion This hypothesis-generating study provides some preliminary evidence for an association between exposure to soluble MWF and increased risk of breast cancer. Additional studies of MWF and breast cancer, with data on known breast cancer risk factors, are warranted. Am. J. Ind. Med. 47:153–160, 2005. © 2005 Wiley-Liss, Inc.

Aims: To estimate the one year cumulative incidence and persistence of upper extremity (UE) soft tissue disorders, in a fixed cohort of automotive manufacturing workers, and to quantify their associations with ergonomic exposures. Methods: At baseline and at follow up, cases of UE musculoskeletal disorders were determined by interviewer administered questionnaire and standardised physical examination of the upper extremities. The interview obtained new data on psychosocial strain and updated the medical and work histories. An index of exposure to ergonomic stressors, obtained at baseline interview, was the primary independent variable. Cumulative incidence and persistence of UE disorders (defined both by symptoms and by physical examination plus symptoms) were analysed in relation to baseline ergonomic exposures, adjusting for other covariates. The incidence of new disorders was modelled using multivariate proportional hazards regression among workers who were not cases in the first year and the prevalence on both occasions was modelled by repeated measures analysis. Results: A total of 820 workers (69% of eligible cohort members) was examined. Follow up varied slightly by department group but not by baseline exposure level or other characteristics. Among the non-cases at baseline, the cumulative incidence of UE disorders was 14% by symptoms and 12% by symptoms plus examination findings. These rates increased with index of physical exposures primarily among subjects who had the same jobs at follow up as at baseline. Increased exposure during follow up increased risk of incidence. The persistence of UE disorders from baseline to follow up examination was nearly 60% and somewhat associated with baseline exposure score. Conclusions: These longitudinal results confirm the previous cross sectional associations of UE musculoskeletal disorders with exposure to combined ergonomic stressors. The exposure-response relation was similar for incident cases defined by symptoms alone and those confirmed by physical examination.

Objectives. This study sought to characterize occupational injury and illness cases identified through 3 different sources of data on a population of immigrant workers. Methods. Participants were Cambodian and Lao workers living in Lowell, Mass. A household survey allowed comparisons between characteristics of work-related cases documented in workers’ compensation wage replacement records and hospital records and characteristics of self-reported cases. Results. The household survey captured types of cases missing from existing data, particularly illnesses self-reported to be associated with chemical exposures. Injuries and illnesses affecting the study population appeared to be significantly underrepresented in workers’ compensation wage replacement data. Conclusions. Community-based methods can supplement available occupational health data sources.

The 2014 International Epidemiology in Occupational Health (EPICOH) meeting in Chicago, USA, focused on the theme: ‘Challenges for Occupational Epidemiology in the 21st Century’. These are exciting times and with them come no end to challenges faced by occupational epidemiology. And participants eagerly engaged in vigorous discussion on a number of current concerns with both wisdom and wit. Ultimately each individual must decide what challenges are most important and how best to address those selected for first order attention. Nonetheless, some overview of challenges could prove worthwhile and so six general areas are provided as a focus for consideration. We always run the risk of studying what we know how to study rather than investigating important problems. We must try our best to tackle broad issues and not restrict ourselves to narrow expressions or concerns. To paraphrase Walter Holland1: Overall the number of conditions and environments studied by occupational epidemiologists needs to be expanded and we must not hesitate to press for resources to investigate and control conditions of little concern to political or commercial interests, but which are of importance to our workers and our societies. Funding for our studies is increasingly difficult but the more important the problem the more likely we can gain the attention of potential funders. It is likely that each of us has a somewhat different view of what are the important problems. One that deserves priority attention is the impact of climate change on the global workforce. There is a remarkably diverse mix of occupational sectors that will bear the consequences of climate change.2 The numbers of workers potentially affected certainly is in the millions, …

Background Office computer workers are at increased risk for neck/upper extremity (UE) musculoskeletal pain. Methods A seven-month office ergonomic intervention study evaluated the effect of two engineering controls plus training on neck/UE pain and mechanical exposures in 113 computer workers, including a 3-month follow-up period. Participants were randomised into an intervention group, who received a keyboard/mouse tray (KBT), touch pad (TP) for the non-dominant hand and keyboard shortcuts, and a control group who received keyboard shortcuts. Participants continued to have available a mouse at the dominant hand. Outcomes were pain severity, computer rapid upper limb assessment (RULA), and hand activity level. Prevalence ratios (PRs) evaluated intervention effects using dichotomised pain and exposure scores. Results In the intervention group, the dominnt proximal UE pain PR=0.9, 95% CI 0.7 to 1.2 and the dominant distal UE PR=0.8, 95% CI 0.5 to 1.3, postintervention. The non-dominant proximal UE pain PR=1.0, 95% CI 0.8 to 1.4, while the non-dominant distal UE PR=1.2, 95% CI 0.6 to 2.2, postintervention. Decreases in non-neutral postures were found in two RULA elements (non-dominant UE PR=0.9, 95% CI 0.8 to 0.9 and full non-dominant RULA PR=0.8, 95% CI 0.8 to 0.9) of the intervention group. Hand activity increased on the non-dominant side (PR=1.4, 95% CI 1.2 to 1.6) in this group. Conclusions While the intervention reduced non-neutral postures in the non-dominant UE, it increased hand activity in the distal region of this extremity. To achieve lower hand activity, a KBT and TP used in the non-dominant hand may not be the best devices to use.

This study examined work-related chronic abnormality in pulmonary function and work-related acute irritant symptoms associated with exposure to borate dust in mining and processing operations. Chronic effects were examined by pulmonary function at the beginning and end of a 7-year interval. Time-specific estimates of sodium borate particulate exposures were used to estimate cumulative exposure during the study interval. Change in pulmonary function over the 7 years was found unrelated to the estimate of cumulative exposure during that interval. Exposure-response associations also were examined with respect to short-term peak exposures and incidence of five symptoms of acute respiratory irritation. Hourly measures of health outcome and continuous measures of particulate exposure were made on each subject throughout the day. Whenever a subject reported one of the irritant symptoms, a symptom intensity score was also recorded along with the approximate time of onset. The findings indicated that exposure-response relationships were present for each of the specific symptoms at several symptom intensity levels. The associations were present when exposure was estimated by both day-long and short-term (15-min) time-weighted average exposures. Associations persisted after taking account of smoking, age, and the presence of a common cold. No significant difference in response rate was found between workers exposed to different types of sodium borate dusts.

We present an epidemiologic approach for the study of the irritant effects of sodium borate exposure that can be used to study acute reversible health effects more generally. Acute irritant responses, such as symptoms of nasal irritation or cough, are subjective. They may, however, be accompanied by transient airway obstruction, which can be objectively measured by a change in peak expiratory flow (PEF) or forced expiratory volume in one second (FEV1). Because these physiologic responses are reversible and follow short-term peaks of exposure, they cannot be studied effectively using conventional epidemiologic methods of design and analysis. The proposed study design is a short-term prospective cohort study with frequently repeated measures of health effects and simultaneous measures of exposure. Because each subject passes through periods of high and low short-term exposure, the study has the form of a crossover design. This design permits each acute response to be linked to the corresponding short-term average exposure, providing the data necessary for dose-response analyses within subject. We present the results of the sodium borate study to illustrate the analysis of such data.

Where have we come since the Occupational Safety and Health Act was passed in 1970? Have we made progress in this country toward "safe and healthful working conditions for working men and women?" Many hazardous exposures that were prevalent before the creation of NIOSH, OSHA, and MSHA have been reduced. Exposure to asbestos, coal dust, silica, lead, and cotton dust are common examples. Through OSHA's Hazard Communication Standard and state Right to Know laws as well as an increase in the dissemination of information, the average employer and worker today is better informed of specific hazards on the job, and more attentive to safety measures. However, the high toll of work related disease and injuries continues today.

A lung cancer case-control study was conducted in a Slovenian asbestos-cement factory for which unusually good records of asbestos exposures were available. The cohort consisted of all 6714 workers employed at the Salonit Anhovo factory after 31 December 1946 who worked there for at least one day between 1964 and 1994. Fifty-eight histologically confirmed cases of primary lung cancer and 290 controls were selected from the cohort. Working life exposure histories to amphibole and chrysotile forms of asbestos were estimated separately. Airborne asbestos concentrations were low. For example, the arithmetic mean exposure to all forms of asbestos in the highest exposure period (1947-1971) was 1.2 f/cm(3). Chrysotile asbestos made up about 90% of this exposure (mean 1.1 f/cm(3)), whereas amphibole accounted for 10% (0.1 f/cm(3)). Comparing those above and below the 90 percentile of cumulative exposure, the odds ratios for all asbestos, chrysotile and amphibole were 1.5, 1.6 and 2.0, respectively, but confidence intervals were wide. There are only a few asbestos-lung cancer studies with high-quality exposure data and exposures in this low range. Though imprecise, the findings are important to the ongoing debate about asbestos risks.

Methods We conducted a cross-sectional study of 3139 children and adolescents from poor areas of the city of Pelotas, southern Brazil. We employed the child behaviour checklist for estimating BP. We performed multivariable analysis using Poisson's regression for confounder control. Results The proportion of workers was 13.8% (7.3% among children and 20.7% among adolescents). Prevalence of BP among workers and prevalence ratios (PRs) were 21.4% (PR = 1.3; CI 0.9-1.9) among children and 9.5% (PR = 0.6; CI 0.4-1.0) among adolescents. Considering workers only, the risk of BP was 2.7 times greater (CI 1.4-5.1) among children when compared with adolescents. Working in domestic services among children and beginning to work at an early age among adolescents were associated with BP. Conclusions Our results reinforce the need for respecting the minimum age for admission to employment established by the ILO Convention 138 and by the Brazilian legislation and contribute to the discussion about the occupations that should be considered as hazardous child labour.

Background The military presents a unique opportunity to study the incidence of disease in a population with complete knowledge of person-time and occupation. Women in the Army are employed more frequently in non-traditional, industrial jobs such as auto mechanic and motor transport operators than in the general US population, increasing the probability of exposure to industrial chemicals. A cohort to investigate the risk of breast cancer among active duty Army women occupationally exposed to volatile organic chemicals (VOCs) was constructed. Methods Age-adjusted incidence rates for breast cancer were calculated for more than 270,000 enlisted women who served between 1980–1996. Twenty-one VOCs, described in previously published literature as having a potential risk of breast cancer, were identified in an Army industrial hygiene survey database. Job title histories were linked to workplace chemical evaluations conducted by Army industrial hygienists, which included a subjective exposure potential rating (high, medium, low, and none) for each VOC. Poisson regression analysis was used to evaluate the association between the exposure rating by job title and breast cancer. Results The incidence of breast cancer in the cohort was significantly elevated in women younger than 35 years of age, especially among black women, when compared to the age-specific rates in the general population. Women who worked in occupations with a moderate to high exposure potential to at least one VOC had a 48% increased risk (P

The prevalence of musculoskeletal disorder (MSD) symptoms and doctor-diagnosed musculoskeletal disorders (DDMDs) were estimated among union construction ironworkers by a telephone-administered questionnaire. Of 1996 ironworkers eligible, 1566 were contacted and 981 were interviewed. The prevalence of self-reported MSD symptoms was high for the lower back (56%), wrist/hands/fingers (40%), knees (39%), and shoulders (36%). The most common DDMDs were tendonitis (19%), ruptured disk in the back (18%), bursitis in the shoulder (15%), and carpal tunnel syndrome (12%). Generally, the prevalence of DDMDs and MSD symptoms increased with duration of employment. In age-adjusted logistic regression analyses, those who worked 25 to 35 years were more likely to have tendonitis (odds ratio [OR] 7.1, 95% confidence interval [CI] 3.116.6), shoulder bursitis (OR 13.7, 95% CI 3.160.4), knee bursitis (OR 5.1, 95% CI 1.025.1), and ruptured intervertebral back disk (OR 6.7, 95% CI 2.617.5). The effect of prior injury was also consistently high (upper extremities, OR 4.6; lower extremities OR 5.1; lower back, OR 6.0). Among workers without prior injuries, MSD symptoms were more frequent for the lower back in structural ironwork (OR 1.7, 95% CI 1.12.6), and for the upper extremity in concrete reinforcement ironwork (OR 1.9, 95% CI 1.22.9). These findings suggest that some musculoskeletal morbidity in construction ironworkers may be work related and thus preventable.

Objective: Prostate cancer is hormone-related and chemicals that interfere with hormones may contribute to carcinogenesis. In a cohort of autoworkers we characterized exposure to metalworking fluids (MWF) into age windows with homogenous biological risk for prostate cancer, and examined exposure–response relationships using semi-parametric modeling. Methods: Incident cases (n=872) were identified via Michigan cancer registry from 1985 through 2000. Controls were selected using incidence-density sampling, 5:1 ratio. Using a hormonal-based model, exposure was accumulated in three windows: (1) late puberty, (2) adulthood, and (3) middle age. We used penalized splines to model risk as a smooth function of exposure, and controlled for race and calendar year of diagnosis in a Cox model. Results: Risk of prostate cancer linearly increased with exposure to straight MWF in the first window, with a relative risk of 2.4 per 10 mg/m3-years. Autoworkers exposed to MWF at a young age also had an increased risk associated with MWF exposure incurred later in life. For soluble MWF there was a slightly increased risk in the third window. Conclusions: Exposure characterization based on a hormonal model identified heightened risk with early age of exposure to straight MWF. Results also support a long latency period for exposure related prostate cancer.

Background Uncontrolled confounding by personal exposures like smoking can limit the inferential power of occupational cohort studies. We developed and demonstrate a refinement of an existing type of sensitivity analysis, indirect adjustment, for evaluating the potential magnitude of confounding by alcohol and tobacco, Results of a large retrospective cohort study of laryngeal cancer and exposure to metalworking fluids (MWF) are used to illustrate the methods. Methods Data on smoking and drinking habits representative of the study cohort were obtained from a sample of US manufacturing workers from the 1977 National Health Interview Survey (NHIS). Two different mechanisms were assumed to affect the distribution of confounding factors between MWF exposure groups: socially determined and chance differences. Chance variation was investigated with Monte Carlo sampling from the NHIS survey distribution of smoking and drinking. An upper bound on systematic differences in smoking and drinking was set by assuming that differences between exposure groups within the same unionized blue collar workforce were very unlikely to be larger than differences between blue and white collar manufacturing workers in the NHIS data. Results Under plausibly large differences in smoking and drinking habits among MWF exposure groups occurring by either mechanism, the exposure-risk association was unlikely to have been over- or under- estimated by as much as 20%. Conclusions When comparing exposure groups within the same working population, it is unlikely that either systematic or chance differences in smoking and drinking habits will cause as much as a 20% change in the relative risk in large studies. While this study focused on an occupational exposure and laryngeal cancer, there are many situations in which epidemiologists are concerned that unmeasured 'lifestyle factors' may differ among exposure groups, and it would appear that the likely confounding effect of such differences will often be modest.

Aims: To re-examine aerodigestive cancer risk in a cohort of autoworkers exposed to metal working fluids (MWF), using improved case definition and more recently diagnosed cases. Methods: The autoworker cohort included 31 100 hourly workers alive on 1 January 1985 who worked at three automobile plants in Michigan. A case-cohort design was carried out that included incident cases of cancers of the larynx, oesophagus, and stomach, and a 10% sample of the cohort. A Cox proportional hazards model was used to estimate MWF exposure effects. The smoothing method of penalised splines was used to explore the shape of the underlying exposure-response curves. Results: The most important finding was the association between larynx cancer incidence and cumulative straight MWF exposure. The results for oesophageal cancer were less consistent. For stomach cancer there was no evidence of excess risk. Conclusion: This association between larynx cancer and straight MWF exposures was consistent with a previous finding in this cohort, providing further support for a causal relation.

To assess the occupational health of a group of vulnerable workers, Southeast Asians, in Lowell, Massachusetts, researchers surveyed 160 residents of Cambodian or Lao ethnicity regarding working conditions, health problems, and use of medical services. Over 40% reported work in electronics and computer assembly. A fourth of those currently employed held temporary jobs. Workplace hazards included soldering fumes; inadequate ventilation; prolonged sitting or standing; awkward postures; unguarded machinery; shift work; long hours; and pressure to produce quickly. Common work-related health problems included sprains and strains, headache, dizziness, and flu-like symptoms. Less than a third of the respondents knew about workers' compensation. Household surveys can provide otherwise unavailable occupational health data for defined populations.

The debate about work-relatedness of musculoskeletal disorders (MSDs) reflects both confusion about epidemiologic principles and gaps in the scientific literature. The physical ergonomic features of work frequently cited as risk factors for MSDs include rapid work pace and repetitive motion, forceful exertions, non-neutral body postures, and vibration. However, some still dispute the importance of these factors, especially relative to non-occupational causes. This paper addresses the controversy with reference to a major report recently commissioned by the US Congress from the National Research Council (NRC) and Institute of Medicine (IOM) (2001). The available epidemiologic evidence is substantial, but will benefit from more longitudinal data to better evaluate gaps in knowledge concerning latency of effect, natural history, prognosis, and potential for selection bias in the form of the healthy worker effect. While objective measures may be especially useful in establishing a more secure diagnosis, subjective measures better capture patient impact. Examination techniques still do not exist that can serve as a ‘‘gold standard’’ for many of the symptoms that are commonly reported in workplace studies. Finally, exposure assessment has too often been limited to crude indicators, such as job title. Worker self-report, investigator observation, and direct measurement each add to understanding but the lack of standardized exposure metrics limits ability to compare findings among studies. Despite these challenges, the epidemiologic literature on work-related MSDs—in combination with extensive laboratory evidence of pathomechanisms related to work stressors—is convincing to most. The NRC/IOM report concluded, and other reviewers internationally have concurred, that the etiologic importance of occupational ergonomic stressors for the occurrence of MSDs of the low back and upper extremities has been demonstrated. # 2003 Elsevier Ltd. All rights reserved.

Aims: To determine chronic effects of long term exposure to cotton dust and endotoxin on incidence of respiratory symptoms and the effect of cessation of exposure. Methods: Respiratory health in 429 Chinese cotton textile workers (study group) and 449 silk textile workers (control group) was followed prospectively from 1981 to 1996. Byssinosis, chest tightness, and non-specific respiratory symptoms were assessed by means of identical standardised questionnaires at four time points. Exposures to cotton dust and endotoxin were estimated using area samples collected at each survey. Incidence and persistence of symptoms were examined in relation to cumulative exposure and exposure cessation using generalised estimating equations (GEE). Results: Among cotton workers, the cumulative incidence of byssinosis and chest tightness was 24% and 23%, respectively, and was significantly more common in smokers than in non-smokers. A high proportion of symptoms was found to be intermittent, rather than persistent. Among silk workers, no typical byssinosis was identified; the incidence of chest tightness was 10%. Chronic bronchitis, cough, and dyspnoea were more common and persistent in the cotton group than in the silk group. Significantly lower odds ratios for symptoms were observed in cotton workers who left the cotton mills; risk was also related to years since last worked. Multivariate analysis indicated a trend for higher cumulative exposure to endotoxin in relation to a higher risk for byssinosis. Conclusion: Chronic exposure to cotton dust is related to both work specific and non-specific respiratory symptoms. Byssinosis is more strongly associated with exposure to endotoxin than to dust. Cessation of exposure may improve the respiratory health of cotton textile workers; the improvement appears to increase with time since last exposure.

The methacholine challenge test protocol was assessed in the reanalysis of three occupational studies. We evaluated the impact of truncating the range of methacholine on responsiveness, as defined by slope and PC(20). In original analysis, reactivity was similar for apprentices and auto body shop workers, whereas boilermakers were more responsive. Truncating high concentrations did not change the classification of subjects with PC(20)

Occupational health surveillance data are key to effective intervention. However, the US Bureau of Labor Statistics survey significantly underestimates the incidence of work-related injuries and illnesses. Researchers supplement these statistics with data from other systems not designed for surveillance. The authors apply the filter model of Webb et al. to underreporting by the Bureau of Labor Statistics, workers’ compensation wage-replacement documents, physician reporting systems, and medical records of treatment charged to workers’ compensation. Mechanisms are described for the loss of cases at successive steps of documentation. Empirical findings indicate that workers repeatedly risk adverse consequences for attempting to complete these steps, while systems for ensuring their completion are weak or absent.

To address earlier reports of excess cancer mortality associated with employment at a large transformer manufacturing plant, each plant operation was rated for seven exposures: Pyranol (a mixture of poly chlorinated biphenyls and trichlorobenzene), trichloroethylene, benzene, mixed solvents, asbestos, synthetic resins, and machining fluids. Site-specific cancer deaths among active or retired employees were cases; controls were selected from deaths (primarily cardiovascular deaths) presumed to be unassociated with any of the study exposures. Using job records, we then computed person-years of exposure for each subject. All subjects were white males. The only unequivocal association was that of resin systems with lung cancer (odds ratio = 2.2 at 16.6 years of exposure, P = 0.001, in a multiple logistic regression including asbestos, age, year of death, and year of hire). Certain other odds ratios appeared larger, but no other association was so robust and remained as distinct after considering the multiplicity of comparisons. Study power was very limited for most associations, and several biases may have affected our results. Nevertheless, further investigation of synthetic resin systems of the type used in the study plant appears warranted.

Field studies of occupational exposure to airborne irritants have predominantly relied on symptom surveys of study participants. As part of a new approach to the study of acute irritant symptoms, subjects exposed to sodium borate dusts recorded their symptom responses at hourly interviews as well as instantaneously on an electronic device called an event marker. Overall, the unprompted marks indicated fewer irritant events than the interviews. Marks were more frequent in the presence of more than one type of symptom and also appeared to reflect more severe symptoms. A proportion of the marked events occurred in time intervals when no symptoms were recalled during the interview. The exposure-response relations were similar regardless of whether they were based on the interview reports or the electronically marked symptoms. The event marker provided a means to examine the time of onset of the acute symptom event. It also made it possible to examine directly the timing profiles of symptom response in relation to changes in exposure levels in a field setting. Despite some inconsistencies, the finding suggests that the event marker may provide an alternative to frequent interviews of exposed workers to obtain irritant symptom responses for exposure-response modeling.

This presentation reviews occupational epidemiology as a foundation for workplace disease prevention activities. By examining descriptive, etiologic and intervention occupational epidemiology studies, a range of opportunities are illustrated where epidemiology has played, or could play a principal role in guiding preventive efforts. Descriptive studies presented include ones based on vital records, on epidemic investigations, cross-sectional surveys, and surveillance. Etiologic studies review the largely successful development of knowledge for lung cancer and asbestos exposure for pulmonary effects of isocyanate exposures. However, attention is also directed to the need for etiologic studies of work environment risks for both cardiovascular and musculoskeletal disease. Finally importance is placed on the too infrequent epidemiologic studies of intervention. Historical examples of control of large risks from nickel cancers and silicosis are balanced with more recent examples of successes at reducing smaller risks of cardiovascular disease and oil acne. Throughout, emphasis is placed on the importance of reintegrating the academic discipline of epidemiology into the application of study findings to prevention of workplace risks.

One hundred forty-four sewing machine operators answered questionnaires concerning occupational history and musculoskeletal symptoms adapted from the National Health and Nutrition Examination Survey. They were matched for age within 5 years, race, and sex with persons completing the HANES I Augmentation Survey, and the prevalence of self-reported musculoskeletal morbidity was compared. Operators complained significantly more often of knee pain (prevalence odds ratio [POR] = 1.84, p = .0001) and knee swelling (POR = 9.98, p less than .00001), although they were no more likely to have had knee surgery. Similar increases were reported for upper-back pain (POR = 2.13, p = .002) joint ache, and joint swelling (both were significant for fingers, wrists, elbows, and shoulders at p less than .05 levels). No differences in low-back pain or in hospitalization for joint conditions were noted. Ergonomic redesign of sewing machines needs to address knee and upper-back movements as well as the arm, wrist, and finger movements.

Analysis of the causes of death among workers employed in the manufacture of synthetic abrasive products was performed using data from death certificates and employment records. The subjects were 1,030 white male workers who had been employed by a single manufacturer and who were identified through a review of death certificates issued during a 20-year period. Proportional mortality analysis revealed excess digestive cancer and respiratory disease deaths. Personnel records permitted refinement of the study population to 968 with classification of each individual into one of seven employment categories. Case-control analysis of workers ever employed in the individual categories revealed elevated odds ratios for respiratory disease deaths among those most exposed to the synthetic abrasive dust. The excesses were greatest in those exposed 20 or more years. Excesses of esophageal and rectal cancers were noted in two manufacturing areas although the numbers were small. Review of the literature further supports the findings that synthetic abrasive exposures may be associated with elevated respiratory morbidity and mortality.

This study was designed to examine whether retail food store employees have an unusual prevalence or incidence of respiratory symptoms or pulmonary function abnormalities attributable to their work environment. The methodology and development of exposure assignments are presented. Employees from 75 supermarkets (a total of 685 meat cutters, wrappers and store clerks) were tested in a base-line survey, and those still available (305) were resurveyed four years later. Each subject completed a standard questionnaire on job history, health history, cigarette smoking, and respiratory symptoms and also performed five forced expiratory efforts on a standardized spirometer. The major air contaminants were identified including the composition and levels of exposures associated with the different ways of cutting plastic film wrap. A cumulative exposure estimate for each subject was made. Parts II and III of this study present the association of these work environment factors with respiratory symptoms and ventilatory function.

A comparison was made between the chief cause of death among 969 deceased white male granite workers in Vermont and the causes of death among other individuals not in that occupation. Tuberculosis deaths were ten times the number predicted, based on the U.S. white male experience. Of the 65 tuberculosis deaths, 48 were silicotuberculosis and 16 were pulmonary tuberculosis. A notable increase was found for deaths due to all respiratory diseases, with 28 deaths due to silicosis. Excluding deaths due to silicosis and tuberculosis left a small excess of emphysema-related deaths. For 25 men in the respiratory disease category whose cause of death was not listed as silicosis, ten had evidence of silicosis in their x-ray records suggesting some misdiagnoses may have occurred. An excess of lung cancer deaths was noted among sawyers and polishers, suggesting possible effects of abrasive exposures. No tuberculosis deaths were noted in men who started work in the post dust control period, after 1950. There was an excess of suicide deaths before 1970.

The overall number of deaths from cancer is increasing. The absolute magnitude of this increase is in debate. Unfortunately, we are unable to estimate the interactions between two or more agents such as cigarettes and asbestos. None of the appropriate studies is precisely able to know the exact exposure to carcinogens. Regardless of the percentage of cancers related to the workplace, the numbers are clearly clinically significant. It is important to present to physicians medical conditions which have an increased probability of resulting from occupational exposure. This will allow clinics, hospitals and health departments to seek evidence of changing patterns or clusters of listed diseases. Individual physicians with a high index of suspicion play an important role in detecting occupational cancers. The current state of the art is, that with rare exceptions, a good occupational history which contributes to a reasonable diagnosis with appropriate background information is the best way for the practicing doctor to detect occupational cancers. All health care providers should look beyond cigarettes as the only cause of cancer worth noting in order to implement primary preventive medicine strategies.

This study examines cancer mortality patterns by occupation for white males in Massachusetts using 1971-1973 death records. Its purpose is to identify occupation-cancer associations that, when interpreted in conjunction with results from other studies and hypotheses about potential occupational carcinogens, can serve as leads for more definitive etiological investigations. Sixty-two malignancy categories (including grouped categories) were investigated for each of 397 occupational categories (including grouped categories) using an age-standardized mortality odds ratio approach. An important finding was the association between lung cancer and a large number of occupations for which there is support from other epidemiologic studies and/or for which there are reasonable hypotheses as to possible carcinogenic exposures. These occupations include truck drivers, painters, machinists, automobile mechanics, plumbers, cooks, fishermen, heated metal workers, sheet metal workers, and brickmasons/stonemasons/tile setters.

The aim of the present study was to evaluate the association and impact of occupational exposure and diseases of the shoulder and neck. Prevalence rates, odds ratios, aetiological fractions, and their confidence intervals were computed for pooled and non-pooled data of previous published reports. By comparison with office workers and farmers, dentists had an increased odds ratio for cervical spondylosis (two studies) and for shoulder joint osteoarthrosis. Meat carriers, miners, and "heavy workers" also had significantly higher rates of cervical spondylosis compared with referents. Compared with iron foundry workers, civil servants had a significant odds ratio (4.8) of cervical disc disease and a 0.79 aetiological fraction. Whether this was due to exposure or healthy worker effect was not clear. In four occupational groups with high shoulder-neck load an odds ratio of 4.0 was found for thoracic outlet syndrome with an aetiological fraction of 0.75. Rotator cuff tendinitis in occupational groups with work at shoulder level (two studies) showed an odds ratio of 11 and an aetiological fraction of 0.91. Keyboard operators had an odds ratio of 3.0 for tension neck syndrome (five studies). Unfortunately, owing to the scanty description of the work task, the exposure could be analysed only by job title. Examination of published reports shows clearly that certain job titles are associated with shoulder-neck disorders. High rates and aetiological fractions for rotator cuff tendinitis and tension neck syndrome suggest that preventive measures could be effective. Although job descriptions are brief, the associations noted suggest that highly repetitive shoulder muscle contractions, static contractions, and work at shoulder level are hazardous exposure factors. In reports of cross sectional studies of occupational shoulder-neck disorders presentation of age, exposure, and effect distribution may help for future meta-analysis.

PreviewAn occupational history is critical not only to accurate diagnosis, treatment, and prevention of work-related diseases and injuries but also to appropriate placement of individuals in the workplace at the start of a new job or on return to work after a serious illness or injury. In this article, Drs Levy and Wegman discuss key parts of the occupational history, questions that will elicit helpful information, and correlation of the findings with diagnosis and treatment.

This study examined the relationships between the prevalence of respiratory tract symptoms and estimates of environmental exposures in retail food stores, in particular exposures to emissions from the cutting of polyvinyl chloride wrap. When respiratory symptoms were compared with a measure of cumulative exposure, there was evidence that the prevalence of symptoms of episodic airway narrowing was higher for workers who had been exposed directly or indirectly to meat wrapping operations independent of a significant association of these symptoms with allergic or asthmatic history. Whether this finding reflects a nonspecific irritant effect or allergic sensitization cannot be determined from these data. No single substance present in the work environment studied has, as yet, been identified as associated with these effects.

Introduction Over 80 million American men and women spend one quarter of their lives in a workplace outside the home. The deterioration in health quality that results from exposure to hazards in th...

Findings are reported from a prospective morbidity study which examined the effects on pulmonary function associated with the particulate and gaseous air contaminants to which retail food store workers are exposed. A total of 685 supermarket employees (including meat wrappers, meat cutters and store clerks) performed standard ventilatory function tests [forced expiratory volume in 1 s (FEV1.0) and forced vital capacity (FVC)] during a base-line survey. Those available four years later (305) were resurveyed in a similar manner. A suggestive chronic effect on pulmonary function was shown in those with high cumulative exposures and allergic history. Among those workers who had continuous exposure to air contaminants in settings with "hot-wire" plastic wrap film cutters the annual rates of change in FEV1.0 and FVC were twice as great as the changes found among comparable workers who were not exposed to fumes from wrapping film. Those who switched from the "hot-wire" to the "cool-rod" cutters during the course of the follow-up had intermediate rates of change in lung function.

From a cohort of 1,768 Boston fire fighters studied initially in 1970, pulmonary function measurements were repeated on 1, 146 active subjects in 1974. The mean time between examinations was 3.4 years. The data on 1,430 subjects after one year of follow-up had indicated excessive decrements in levels of forced vital capacity and one-second forced expiratory bolume which were related to the frequency of fire exposure. The annual decline over three years was less than that observed over one year and could not be related to the number of fires fought or to other indices of acute fire exposure. Selection factors within the fire department appear to be important in protecting fire fighter from continued loss ventilatory capacity.

Miners and millers of talc ore, free from asbestos and silica, were examined for respiratory effects. A study of 116 subjects included the modified British Medical Research Council respiratory symptom questionnaire, simple spirometry, chest radiography, and limited examination of the chest. A one-year follow-up evaluation was performed on 103 subjects. Of the 12 subjects whose chest radiographs showed small round or irregular opacities (perfusion 1/0 or greater), five had never smoked cigarettes. Pulmonary function values at the time of the initial study were less than predicted and the rates of loss of FEV1 and FVC greater than expected. These differences were in part attributed to cigarette smoking but were greater than predicted from that source alone. There was evidence of an exposure effect after adjusting for cigarette smoking and we conclude that these workers have been affected by their exposures. No clear interaction between smoking and exposure could be identified. Populations such as this will need to be studied for longer periods to determine what current dust levels are safe.

The size distribution measurements of lead aerosol from a brass foundry and primary lead smelter are used to simulate blood lead distributions applying a pharmacokinetic model developed by Bernard. The predicted distribution of blood lead levels determined using the actual size distribution of lead aerosol are compared to the blood lead levels predicted according to the model assumptions adopted in setting the OSHA lead standard. In the furnace area of the smelter and the pouring area of the foundry the predicted mean blood lead level is higher than that found in the standard whereas, in the smelter's sintering and mixing operation the blood lead level is less than that suggested by the standard. The data support the conclusion that size-selective sampling needs to be considered for incorporation into the OSHA lead standard.

This paper describes our experience with the respiratory effects of TDI. Five respiratory reactions attributable to TDI are described with supporting evidence. The reactions are sensitization, irritation from overexposure, acute loss of ventilatory capacity, accelerated loss of pulmonary function and induction of a general asthmatic state. Evidence is presented that suggests a safe exposure level.