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BackgroundUnder-reporting of occupational injuries (OIs) among precariously employed workers in Sweden challenges effective surveillance of OIs and targeted preventive measures.ObjectiveTo estimate the magnitude of under-reporting of OIs among precarious and non-precarious workers in Sweden in 2013.MethodsCapture–recapture methods were applied using the national OIs register and records from a labour market insurance company. Employed workers 18–65 resident in Sweden in 2013 were included in the study (n=82 949 OIs). Precarious employment was operationalised using the national labour market register, while injury severity was constructed from the National Patient Register. Under-reporting estimates were computed stratifying by OIs severity and by sociodemographic characteristics, occupations and precarious employment.ResultsUnder-reporting of OIs followed a dose–response pattern according to the levels of precariousness (the higher the precarious level, the higher the under-reporting) being for the precarious group (22.6%, 95% CI 21.3% to 23.8%), followed by the borderline precarious (17.6%, 95% CI 17.1% to 18.2%) and lastly the non-precarious (15.0%, 95% CI 14.7% to 15.3%). Under-reporting of OIs, decreased as the injury severity increased and was higher with highest level of precariousness in all groups of severity. We also observed higher under-reporting estimates among all occupations in the precarious and borderline precarious groups as compared with the non-precarious ones.ConclusionsThis is the first register-based study to empirically demonstrate in Sweden that under-reporting of OIs is 50% higher among precariously employed workers. OIs under-reporting may represent unrecognised injuries that especially burden precariously employed workers as financial, health and social consequences shift from the employer to the employee.

Occupational heat exposure is linked to the development of kidney injury and disease in individuals who frequently perform physically demanding work in the heat. For instance, in Central America, an epidemic of chronic kidney disease of nontraditional origin (CKDnt) is occurring among manual laborers, whereas potentially related epidemics have emerged in India and Sri Lanka. There is growing concern that workers in the United States suffer with CKDnt, but reports are limited. One of the leading hypotheses is that repetitive kidney injury caused by physical work in the heat can progress to CKDnt. Whether heat stress is the primary causal agent or accelerates existing underlying pathology remains contested. However, the current evidence supports that heat stress induces tubular kidney injury, which is worsened by higher core temperatures, dehydration, longer work durations, muscle damaging exercise, and consumption of beverages containing high levels of fructose. The purpose of this narrative review is to identify occupations that may place US workers at greater risk of kidney injury and CKDnt. Specifically, we reviewed the scientific literature to characterize the demographics, environmental conditions, physiological strain (i.e., core temperature increase, dehydration, heart rate), and work durations in sectors typically experiencing occupational heat exposure, including farming, wildland firefighting, landscaping, and utilities. Overall, the surprisingly limited available evidence characterizing occupational heat exposure in US workers supports the need for future investigations to understand this risk of CKDnt.

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.

ObjectiveTo estimate the magnitude of under-reporting of non-fatal occupational injuries (OIs) by different organisational factors in Sweden for the year 2013.MethodsCapture–recapture methods were applied using two data sources: (1) the national OI register and (2) records from a labour market insurance company. To assure comparability of data sources, the analysis was restricted to the public sector and private companies with at least 50 employees. OIs were matched using personal identification number and reported injury dates (±7 days). Organisational factors were obtained from the national labour market register and injury severity (no healthcare/only outpatient/hospitalised) from the National Patient Register. Total number of OIs and ascertainment by data sources were estimated assuming data source independence.ResultsThere were an estimated 98 493 OIs in 2013. Completeness of reporting OIs to the national register and to the insurance company was estimated at 73% and 43%, respectively. No report to either source was estimated at 15 000 OIs (~15%). Under-reporting to the national register differed by selected organisational factors, being higher among organisations in the public sector, those with more females, with a younger workforce and with a higher proportion of immigrants. Overall under-reporting was more common in agriculture (19.7%), other services (19.3%), commerce and hospitality (19.1%), health (18.4%) and education (18.4%). Under-reporting decreased as injury severity increased, with little variations across sectors of economic activity.ConclusionsResults suggest considerable under-reporting of OIs in Sweden and differential under-reporting by organisational factors. Results are relevant for official estimates of burden and for setting priorities for workplace safety and prevention.

BackgroundPrecarious employment is a significant determinant of population health and health inequities and has complex public health consequences both for a given nation and internationally. Precarious employment is conceptualized as a multi-dimensional construct including but not limited to employment insecurity, income inadequacy, and lack of rights and protection in the employment relation, which could affect both informal and formal workers. The purpose of this review is to identify, appraise, and synthesize existing research on the effectiveness of initiatives aiming to or having the potential to eliminate, reduce, or mitigate workers’ exposure to precarious employment conditions and its effects on the health and well-being of workers and their families.MethodsThe electronic databases searched (from January 2000 onwards) are Scopus, Web of Science Core Collection, and PubMed, along with three institutional databases as sources of grey literature. We will include any study (e.g. quantitative, qualitative, or mixed-methods design) evaluating the effects of initiatives that aim to or have the potential to address workers’ exposure to precarious employment or its effects on the health and well-being of workers and their families, whether or not such initiatives were designed specifically to address precarious employment. The primary outcomes will be changes in (i) the prevalence of precarious employment and workers’ exposure to precarious employment and (ii) the health and well-being of precariously employed workers and their families. No secondary outcomes will be included. Given the large body of evidence screened, the initial screening of each study will be done by one reviewer, after implementing several strategies to ensure decision-making consistency across reviewers. The screening of full-text articles, data extraction, and critical appraisal will be done independently by two reviewers. Potential conflicts will be resolved through discussion. Established checklists will be used to assess a study’s methodological quality or bias. A narrative synthesis will be employed to describe and summarize the included studies’ characteristics and findings and to explore relationships both within and between the included studies.DiscussionWe expect that this review’s findings will provide stakeholders interested in tackling precarious employment and its harmful health effects with evidence on effectiveness of solutions that have been implemented to inform considerations for adaptation of these to their unique contexts. In addition, the review will increase our understanding of existing research gaps and enable us to make recommendations to address them. Our work aligns with the sustainable development agenda to protect workers, promote decent work and economic growth, eliminate poverty, and reduce inequalities.Systematic review registrationPROSPEROCRD42020187544.

Objective The aim of this study was to investigate risk factors for retinal detachment or tear (RD/T), and follow up two studies that found increased risk from work-related heavy lifting. Methods We conducted a case-control study including 200 cases of RD/T and 415 controls. Participants completed a questionnaire covering general health, vision, and physical exertion. Multiple logistic regression and propensity score matching was used to control confounding and estimate independent effects. Results RD/T risk was increased by one lifting measure: current regular lifting of more than 30 lbs (>13.6 kg). In the population aged less than 65 years, the odds ratio comparing those with/without heavy lifting was 1.81, 95% confidence interval = 1.08 to 3.04. Conclusion Occupational heavy lifting may represent a risk factor for RD/T, but further research is needed in populations with frequent heavy physical exertion to more precisely quantify the risk.

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.

Saudi Arabia (SA) is one of the hottest countries in the world. This study was conducted to assess the impact of summer heat stress in Southeastern SA on short-term kidney injury (KI) among building construction workers and to identify relevant risk factors. Measurements of urinary albumin-creatinine ratio (ACR), height, weight, hydration, symptoms, daily work and behavioral factors were collected in June and September of 2016 from a cohort of construction workers (n = 65) in Al-Ahsa Province, SA. KI was defined as ACR &ge, 30 mg/g. Multivariate linear regression analysis was used to assess factors related to cross-summer changes in ACR. A significant increase in ACR occurred among most workers over the study period, incidence of KI was 18%. Risk factors associated with an increased ACR included dehydration, short sleep, and obesity. The findings suggest that exposure to summer heat may lead to the development of KI among construction workers in this region. Adequate hydration and promotion of healthy habits among workers may help reduce the risk of KI. A reduction in work hours may be the most effective intervention because this action can reduce heat exposure and improve sleep quality.

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.

Objectives Assess the impact of summer heat exposure (June–September) on residential construction workers in Al-Ahsa, Saudi Arabia by evaluating (i) heart rate (HR) responses, hydration status, and physical workload among workers in indoor and outdoor construction settings, (ii) factors related to physiological responses to work in hot conditions, and (iii) how well wet-bulb globe temperature-based occupational exposure limits (WBGTOELs) predict measures of heat strain. Methods Twenty-three construction workers (plasterers, tilers, and laborers) contributed 260 person-days of monitoring. Workload energy expenditure, HR, fluid intake, and pre- and postshift urine specific gravity (USG) were measured. Indoor and outdoor heat exposures (WBGT) were measured continuously and a WBGTOEL was calculated. The effects of heat exposure and workload on heart rate reserve (HRR), a measure of cardiovascular strain, were examined with linear mixed models. A metric called ‘heat stress exceedance’ (HSE) was constructed to summarize whether the environmental heat exposure (WBGT) exceeded the heat stress exposure limit (WBGTOEL). The sensitivity and specificity of the HSE as a predictor of cardiovascular strain (HRR ≥30%) were determined. Results The WBGTOEL was exceeded frequently, on 63 person-days indoors (44%) and 91(78%) outdoors. High-risk HRR occurred on 26 and 36 person-days indoors and outdoors, respectively. The HSE metric showed higher sensitivity for HRR ≥30% outdoors (89%) than indoors (58%) and greater specificity indoors (59%) than outdoors (27%). Workload intensity was generally moderate, with light intensity work more common outdoors. The ability to self-pace work was associated with a lower frequency of HRR ≥30%. USG concentrations indicated that workers began and ended their shifts dehydrated (USG ≥1.020). Conclusions Construction work where WBGTOEL is commonly exceeded poses health risks. The ability of workers to self-pace may help reduce risks.

IntroductionThere is uncertainty regarding the trends in occupational injuries (OIs) in Sweden due to a significant and increasing problem with under-reporting to injury registers. Under-reporting, in general, is likely to be exacerbated by the rise in precarious employment (PE), a set of unfavourable employment characteristics that would benefit from formal definition and study. PE and global trends are believed also to affect companies and their commitment to health and safety. The present study attempts to bridge these knowledge gaps and presents a study protocol for planned studies, with three main objectives: first, to review the literature for definitions of PE emphasising those that are multidimensional and operationalise components in routinely collected register data; second, to estimate the under-reporting of OI in Swedish registers and third, using results from the first objective, to conduct large, register-based prospective studies, designed to measure effect sizes and interactions between PE, business performance and OI.Methods and analysisFirst, a scientific literature review will be conducted, including scientific databases and grey literature. Second, data from two major OI registers will be used to estimate the magnitude of under-reporting using capture–recapture methodology. Finally, all residents aged 18–65 in Sweden with any registered income during 2003–2015 will be included. Data sources encompass Swedish population and labour market registers with linkage to both the main OI register with national coverage and hospital records. Trends in PE and OI will be explored, together with risk of OI associated with PE and business performance.Ethics and disseminationThe project has been approved by the Regional Ethics Committee, Stockholm (dnr: 2016/2325–31; 2017/2173–32). Dissemination of study results will include a series of peer-reviewed papers, at least one PhD thesis and one report in Swedish, engaging relevant stakeholders. Results will be presented in national and international conferences and through press releases to mass media.

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.

There is a long and continuing legacy of epidemiologists from high income countries conducting occupational health research in low and middle income countries. Opportunities to investigate occupational hazards in relatively high exposure settings and to develop multi-country research partnerships that can lead to disease prevention globally are the main motivations for this type of research. However, it should be appreciated that changes in the cultural, economic, and political environment of the country where the research is conducted can have profound influences on the likelihood of research success. Our research groups have long histories of conducting epidemiologic investigations among textile workers in Shanghai, China. The research includes studies of multiple different cancers and parkinsonism (HC) and respiratory disorders (DCC) in relation to exposures to textile industry dusts and chemicals. Several gene/environment investigations have also been conducted. We present the historical background leading to the research, and the logistical challenges that have emerged over time as political, social, and economic conditions in Shanghai have changed. These challenges include reduced access to workplaces, reduced worker participation rates, and governmentally imposed restrictions on transporting bio-specimens outside of China. Based on our experiences, we can offer some recommendations that occupational epidemiologists in high and low/middle income countries might consider to facilitate collaborative research: being cognizant of national and regional political, social, and economic policy changes; maintaining flexibility in research protocols and budgetary allocations during the course of study conduct; and, keeping lines of communication open throughout the research design and implementation.

Background In Mesoamerica CKDu(Chronic Kidney Disease of unknown cause) is epidemic among sugarcane workers and present in other workers. Excessive heat stress and workload are believed to contribute to onset and acceleration of CKDu. The Worker Health and Efficiency (WE) Program is the first evaluated intervention to address excessive heat stress and workload in sugarcane workers. We used the resulting press, political and industry attention to push for a wider agenda of worker protections. Objectives • Evaluate impact of intervention on patterns of heat illness/dehydration, kidney function, physical workload and productivity. • Demonstrate need for governments and industry to address CKDu and excessive heat stress in sugarcane- and other workers. Methods The WE intervention was piloted in two cohorts of workers, one inland and one coastal sugarcane cutters (totaling 117 individuals); thus, allowing assessment of the intervention via self-controls. Concurrently, outreach to industries and governments was conducted to exchange information. Using press and myriad contacts, private and public policy began to rapidly change. Results Pilot data analysis demonstrated a decrease in heat-related illness, improved hydration, and possibly a stabilisation in kidney function. Marked increase in productivity was also observed. The results drove policy discussions and measurable change in several companies, and the U.S. and Costa Rican Governments. Conclusion An evidenced-based dialogue between sugar industry farmers, millers, buyers, and governments was created. There are several challenges that remain, and navigating the path to where we are holds valuable lessons for those doing similar work.

Climate changes will markedly affect working people as increased heat and extreme weather may directly affect health and indirectly via reduced food access and spread of vector-borne diseases among outdoor workers. The effects will primarily affect low income people in tropical and sub-tropical areas, but occupational health authorities in all countries need to consider the emerging challenges. A recent EU project (www.HEAT-SHIELD.eu) is dedicated to improving heat resilience in workers, and NIOSH/USA recently (2016) published new guidelines. Considering the theme Eliminating Occupational Disease , a widespread occupational health threat from climate change will be excessive heat exposure causing ” workplace heat related illnesses ”. This is already a major problem in large parts of the world. A number of aspects of the occupational health challenges will be presented during this Mini-Symposium. Translating research into action involves broadening existing research/analysis to produce improved ”heat exposure evaluation” and ”occupational health impact assessment” related to climate change. Research needs to identify remediable conditions and solutions/interventions. This requires a major increase in occupational epidemiology studies (including intervention studies), focusing on hot parts of the world. The detrimental health and economic impacts should encourage global and national policies to address climate change mitigation. The Mini-Symposium will consider how to address these needs, and encourage networking among scientists in different fields for future studies. It also aims to engage young scientists in a field which has been overlooked in climate change impact analysis. The HEAT-SHIELD project welcomes cooperation in specific studies and sharing of methodologies.

The death toll of the epidemic of chronic kidney disease of nontraditional origin (CKDnt) in Mesoamerica runs into the tens of thousands, affecting mostly young men. There is no consensus on the etiology. Anecdotal evidence from the 1990s pointed to work in sugarcane; pesticides and heat stress were suspected. Subsequent population-based surveys supported an occupational origin with overall high male-female ratios in high-risk lowlands, but small sex differences within occupational categories, and low prevalence in non-workers. CKDnt was reported in sugarcane and other high-intensity agriculture, and in non-agricultural occupations with heavy manual labor in hot environments, but not among subsistence farmers. Recent studies with stronger designs have shown cross-shift changes in kidney function and hydration biomarkers and cross-harvest kidney function declines related to heat and workload. The implementation of a water-rest-shade intervention midharvest in El Salvador appeared to halt declining kidney function among cane cutters. In Nicaragua a water-rest-shade program appeared sufficient to prevent kidney damage among cane workers with low-moderate workload but not among cutters with heaviest workload. Studies on pesticides and infectious risk factors have been largely negative. Non-occupational risk factors do not explain the observed epidemiologic patterns. In conclusion, work is the main driver of the CKDnt epidemic in Mesoamerica, with occupational heat stress being the single uniting factor shown to lead to kidney dysfunction in affected populations. Sugarcane cutters with extreme heat stress could be viewed as a sentinel occupational population. Occupational heat stress prevention is critical, even more so in view of climate change.La mortalidad por la epidemia de enfermedad renal crónica de origen no tradicional (ERCnt) en Mesoamérica asciende a decenas de miles de personas, principalmente hombres jóvenes. No existe consenso sobre su etiología. En la década de 1990, informes anecdóticos apuntaban como factor de riesgo al trabajo en plantaciones de caña de azúcar; se consideró como posibles causantes a los plaguicidas y el estrés térmico. Estudios de prevalencia de base poblacional subsiguientes apoyaron un origen ocupacional, con una proporción elevada de hombres respecto de las mujeres en las tierras bajas donde el riesgo era elevado, pero con pequeñas diferencias de sexo dentro de las categorías ocupacionales y baja prevalencia en el ámbito no laboral. Se reportó ERCnt en los trabajadores de la caña de azúcar y otros cultivos con alta exigencia física y en ocupaciones no agrícolas que implican trabajo manual intenso en ambientes calurosos, pero no entre los agricultores de subsistencia. Estudios recientes con diseños más sólidos han demostrado cambios en la función renal y en los biomarcadores de hidratación en el curso de los turnos laborales, y disminución de la función renal relacionada con el calor y la carga de trabajo en el curso de la cosecha. La implementación de una intervención basada en la provisión de agua, descanso y sombra a mitad de la cosecha en El Salvador detuvo la disminución de la función renal en los cortadores de caña. En Nicaragua, un programa de provisión de agua, descanso y sombra evitó la lesión renal en los trabajadores de la caña con una carga de trabajo baja y moderada, pero no entre los cortadores, quienes tienen la mayor carga de trabajo. Los estudios sobre plaguicidas y factores de riesgo infecciosos han sido en gran medida negativos. Los factores de riesgo no ocupacionales no explican los patrones epidemiológicos observados. En conclusión, el trabajo es el principal desencadenante de la epidemia de ERCnt en Mesoamérica, y el estrés térmico ocupacional es el único factor que consistentemente conduce a la disfunción renal en las poblaciones afectadas. Los cortadores que trabajan en los ingenios azucareros y están expuestos a un estrés térmico extremo podrían ser considerados una población ocupacional centinela. La prevención del estrés térmico ocupacional es crítica, más aún si se consideran los efectos del cambio climático.A mortalidade devida à epidemia de doença renal crônica de origem não tradicional (DRCnt) na Mesoamérica atinge dezenas de milhares de pessoas, principalmente homens jovens. Não há consenso sobre a sua etiologia. Na década de 1990, informações empíricas apontavam o trabalho em plantações de cana de açúcar como um fator de risco; pesticidas e estresse térmico também eram considerados causas possíveis. As pesquisas populacionais subsequentes sustentam uma origem ocupacional da doença, com uma elevada proporção de homens quando comparados à de mulheres, em areas de baixa altitude, onde o risco da doença é mais elevado, mas com pequenas diferenças de gênero quando se consideram as categorias ocupacionais e baixa prevalência no ambiente não-ocupacional. A DRCnt foi identificada em trabalhadores agrícolas da cana de açúcar e de outras culturas que exigem trabalho físico de alta intensidade e em ocupações não agrícolas envolvendo um trabalho manual intenso em ambientes quentes, mas não entre os agricultores de subsistência. Estudos recentes com desenhos mais robustos demonstraram mudanças na função renal e nos biomarcadores de hidratação ao longo dos turnos de trabalho, e diminuição da função renal relacionada à exposição ao calor e à carga de trabalho ao longo da colheita. A implementação de uma intervenção de água-descanso-sombra durante a colheita em El Salvador interrompeu o declínio da função renal em cortadores de cana. Na Nicarágua, intervenções água-descanso-sombra parecem ter sido suficientes para evitar lesões renais em trabalhadores canavieiros com cargas de trabalho baixa e moderada, mas não entre os cortadores de cana que têm carga de trabalho mais pesada. Estudos sobre exposição a pesticidas e a fatores de risco de origem infecciosa têm sido largamente negativos. Os fatores de risco não-ocupacionais não explicam os padrões epidemiológicos observados. Em conclusão, ocupação é o principal desencadeador da epidemia de DRCnt na Mesoamérica, e o estresse térmico ocupacional é o único fator comprovado que leva à disfunção renal nas populações afetadas. Os cortadores de cana que trabalham em engenhos de açúcar e expostos a um estresse térmico extremo podem ser considerados uma população ocupacional sentinela. A prevenção do estresse térmico ocupacional é crítica, especialmente considerando os efeitos das mudanças climáticas.

SALTRA, IRET, IMM Program on Work, Environment and Health in Central America Programa de Trabajo, Ambiente y Salud en Centroamérica The First International Research Workshop on Mesoamerican Nephropathy (MeN) met in Costa Rica in November 2012 to discuss how to establish the extent and degree of MeN, examine relevant causal hypotheses, and focus efforts to control or eliminate the disease burden. MeN describes a devastating epidemic of chronic kidney disease of unknown origin predominantly observed among young male sugarcane cutters. The cause of MeN remains uncertain; however, the strongest hypothesis pursued to date is repeated episodes of occupational heat stress and water and solute loss, probably in combination with other potential risk factor(s), such as nonsteroidal anti-inflammatory drug and other nephrotoxic medication use, inorganic arsenic, leptospirosis, or pesticides. At the research workshop, clinical and epidemiologic case definitions were proposed in order to facilitate both public health and research efforts. Recommendations emanating from the workshop included measuring workload, heat, and water and solute loss among workers; quantifying nephrotoxic agents in drinking water and food; using biomarkers of early kidney injury to explore potential causes of MeN; and characterizing social and working conditions together with methods for valid data collection of exposures and personal risk factors. Advantages and disadvantages of different population study designs were detailed. To elucidate the etiology of MeN, multicountry studies with prospective cohort design, preferably integrating an ecosystem health approach, were considered the most promising. In addition, genetic, experimental, and mechanistic methods and designs were addressed, specifically the need for kidney biopsy analysis, studies in animal models, advances in biomarkers, genetic and epigenetic studies, a common registry and repository of biological and demographic data and/or specimens, and other areas of potential chronic kidney disease experimental research. Finally, in order to improve international collaboration on MeN, workshop participants agreed to establish a research consortium to link these Mesoamerican efforts to other efforts worldwide. El Primer Taller Internacional de Investigación sobre Nefropatía Mesoamericana (MeN) se reunió en Costa Rica en noviembre de 2012 para discutir cómo establecer la extensión y el grado de MeN, examinar hipótesis causales relevantes y enfocar los esfuerzos para controlar o eliminar la carga de la enfermedad. MeN describe una devastadora epidemia de enfermedad renal crónica de origen desconocido que se observa predominantemente entre los hombres jóvenes cortadores de caña de azúcar. La causa de MeN sigue siendo incierta; sin embargo, la hipótesis más fuerte perseguida hasta la fecha son los episodios repetidos de estrés por calor ocupacional y pérdida de agua y solutos, probablemente en combinación con otros factores de riesgo potenciales, como el uso de medicamentos antiinflamatorios no esteroideos y otros medicamentos nefrotóxicos, arsénico inorgánico, leptospirosis o pesticidas. En el taller de investigación, se propusieron definiciones de casos clínicos y epidemiológicos con el fin de facilitar tanto la salud pública como los esfuerzos de investigación. Las recomendaciones que surgieron del taller incluyeron medir la carga de trabajo, el calor y la pérdida de agua y solutos entre los trabajadores; cuantificación de agentes nefrotóxicos en agua potable y alimentos; el uso de biomarcadores de lesión renal temprana para explorar las posibles causas de MeN; y caracterizar las condiciones sociales y laborales junto con métodos para la recopilación de datos válidos de exposiciones y factores de riesgo personales. Se detallaron las ventajas y desventajas de los diferentes diseños de estudios de población. Para dilucidar la etiología de MeN, los estudios multinacionales con diseño de cohortes prospectivo, preferiblemente integrando un enfoque de salud ecosistémica, se consideraron los más prometedores. Además, se abordaron métodos y diseños genéticos, experimentales y mecanicistas, específicamente la necesidad de análisis de biopsias renales, estudios en modelos animales, avances en biomarcadores, estudios genéticos y epigenéticos, un registro y repositorio común de datos biológicos y demográficos y / o especímenes y otras áreas de investigación experimental potencial de enfermedad renal crónica. Finalmente, con el fin de mejorar la colaboración internacional sobre MeN, los participantes del taller acordaron establecer un consorcio de investigación para vincular estos esfuerzos mesoamericanos con otros esfuerzos en todo el mundo. O Primeiro Workshop Internacional de Pesquisa sobre Nefropatia Mesoamericana (MeN) se reuniu na Costa Rica em novembro de 2012 para discutir como estabelecer a extensão e o grau de MeN, examinar hipóteses causais relevantes e concentrar esforços para controlar ou eliminar a carga da doença. MeN descreve uma epidemia devastadora de doença renal crônica de origem desconhecida observada predominantemente entre jovens cortadores de cana do sexo masculino. A causa do MeN permanece incerta; no entanto, a hipótese mais forte perseguida até o momento são episódios repetidos de estresse calórico ocupacional e perda de água e soluto, provavelmente em combinação com outro (s) fator (es) de risco potencial (s), como o uso de antiinflamatórios não esteróides e outros medicamentos nefrotóxicos, arsênico inorgânico, leptospirose , ou pesticidas. No workshop de pesquisa, definições de casos clínicos e epidemiológicos foram propostas a fim de facilitar os esforços de saúde pública e de pesquisa. As recomendações emanadas da oficina incluíram a medição da carga de trabalho, calor e perda de água e soluto entre os trabalhadores; quantificar agentes nefrotóxicos em água potável e alimentos; usando biomarcadores de lesão renal precoce para explorar causas potenciais de MeN; e caracterizar as condições sociais e de trabalho juntamente com métodos para coleta de dados válidos de exposições e fatores de risco pessoais. Vantagens e desvantagens de diferentes desenhos de estudo populacional foram detalhadas. Para elucidar a etiologia do MeN, estudos multinacionais com desenho de coorte prospectivo, preferencialmente integrando uma abordagem de saúde do ecossistema, foram considerados os mais promissores. Além disso, métodos e designs genéticos, experimentais e mecanísticos foram abordados, especificamente a necessidade de análise de biópsia renal, estudos em modelos animais, avanços em biomarcadores, estudos genéticos e epigenéticos, um registro comum e repositório de dados biológicos e demográficos e / ou espécimes e outras áreas de pesquisa experimental em potencial para doença renal crônica. Finalmente, a fim de melhorar a colaboração internacional no MeN, os participantes do workshop concordaram em estabelecer um consórcio de pesquisa para vincular esses esforços mesoamericanos a outros esforços em todo o mundo. Universidad Nacional, Costa Rica Karolinska Institutet, Sweden Lund University, Sweden Umeå University, Sweden University of Massachusetts Lowell, United States Instituto Regional de Estudios en Sustancias Tóxicas

The epidemic of chronic kidney disease of unknown etiology in Mesoamerica : a call for interdisciplinary research and action

To examine barriers community health centers (CHCs) face in using workers' compensation insurance (WC).Leadership of CHCs in Massachusetts.We used purposeful snowball sampling of CHC leaders for in-depth exploration of reimbursement policies and practices, experiences with WC, and decisions about using WC. We quantified the prevalence of perceived barriers to using WC through a mail survey of all CHCs in Massachusetts.Emergent coding was used to elaborate themes and processes related to use of WC. Numbers and percentages of survey responses were calculated.Few CHCs formally discourage use of WC, but underutilization emerged as a major issue: "We see an awful lot of work-related injury, and I would say that most of it doesn't go through workers' comp." Barriers include lack of familiarity with WC, uncertainty about work-relatedness, and reliance on patients to identify work-relatedness of their conditions. Reimbursement delays and denials lead patients and CHCs to absorb costs of services.Follow-up studies should fully characterize barriers to CHC use of WC and experiences in other states to guide system changes in CHCs and WC agencies. Education should target CHC staff and workers about WC.

Introduction CKD unrelated to diabetes or hypertension is epidemic in Central America. Sugarcane workers are among the most affected with heat stress and dehydration suggested as central factors. An intervention on these factors accompanied by productivity improvements was piloted in El Salvador during the 2014–15 harvest. Methods The intervention adapted OSHA’s Water.Rest.Shade (W.R.S.) hot work guidelines mid-way through the harvest for one inland cutting group. Water was provided in individual backpacks along with mobile shaded rest areas and scheduled rest periods. Ergonomically improved machetes and efficiency strategies were implemented for productivity. Health data (anthropometric, blood, urine, questionnaires) were collected four () times over six months. Daily wet bulb globe temperatures (WBGT) were recorded at inland and coastal worksites. The employer provided production records. Results WBGT exceeded OSHA’s limits for continuous work from 9 AM onwards and exceeded OSHA’s highest limit (i.e., 30°C WBGT, requiring 45 min rest/hour) for 14% and 38% of hours worked at inland and coastal worksites, respectively. Post-intervention, self-reported water consumption increased 25%. Symptom surveys suggested reduction in most heat stress and/or dehydration symptoms. Daily production increased significantly post intervention exceeding productivity increases for most other cutting groups. Focus groups reported positive perception for both the W.R.S. program and the productivity improvements. Preliminary analysis of kidney function show decreased eGFR during the first two months of work before receiving the intervention but did not decrease further thereafter. Conclusion A W.R.S. and efficiency intervention is feasible for manual sugarcane cutters. The intervention demonstrated reduced heat stress symptoms and higher intake of water. The combination of W.R.S. with efficiency measures also improved individual productivity without negative effects on health and well-being. Initial adoption by participants and the company is encouraging, as is interest from labour ministries of El Salvador and Costa Rica.

In the last twenty years, tropical Pacific lowlands of Central America have seen a dramatic increase of a rapidly progressive chronic kidney disease of unknown aetiology (CKDu), the Mesoamerican nephropathy (MeN). MeN is unexplained by conventional CKD risk factors. An international expert workshop held in November 2015 in Costa Rica reached consensus that MeN has a major occupational component with growing evidence for a causal role of strenuous work, heat and insufficient rehydration. Other factors may also play a role, among which agrochemicals is possibly most notable. CKDu occurs in particular among sugarcane cutters, but also among workers in other hot occupations such as construction and mining, whereas it is mostly absent in occupations with less physical effort or in cooler environments. In community-based prevalence studies in Nicaragua and El Salvador, 18–42% of adult males in lowland sugarcane areas had eGFR Similar CKDu epidemics are occurring in tropical agricultural populations in Sri Lanka and India, and possibly in other countries, but it is unclear if the same risk factors play a role.

We, from the Consortium on the Epidemic of Nephropathy in Central America and Mexico (CENCAM), read with interest Drs Subramanian and Javaid's letter,1 regarding Mesoamerican Nephropathy (MeN), a name assigned to a type of chronic kidney disease (CKD) not related to classic risk factors and also referred to as CKD of unknown (CKDu) or non-traditional causes. MeN is highly prevalent in Central America and a major health problem.2 We agree with the authors that it is important to focus attention on the occupational component of this disease, …

This report provides an overview of physical ergonomic exposures in highway construction work across trades and major operations. For each operation, the observational method “PATH” (Posture, Activity, Tools and Handling) was used to estimate the percentage of time that workers spent in specific tasks and with exposure to awkward postures and load handling. The observations were carried out on 73 different days, typically for about 4 h per day, covering 120 construction workers in 5 different trades: laborers, carpenters, ironworkers, plasterers, and tilers. Non-neutral trunk postures (forward or sideways flexion or twisting) were frequently observed, representing over 40% of observations for all trades except laborers (28%). Kneeling and squatting were common in all operations, especially tiling and underground utility relocation work. Handling loads was frequent, especially for plasterers and tilers, with a range of load weights but most often under 15 pounds. The results of this study provide quantitative evidence that workers in highway tunnel construction operations are exposed to ergonomic factors known to present significant health hazards. Numerous opportunities exist for the development and implementation of ergonomic interventions to protect the health and safety of construction workers.

The authors reflect on the health effects that climate change can have and is having in 2014 on employees in the U.S. They suggest that while climate change is having an impact on several emplyee sectors, the issue has not been addressed. They argue that in the U.S. there are no regulatory standards related to climate change linked health hazards and that action should be taken at local, state and federal levels to reduce workers' vulnerability to climate change related issues.

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.

Editorial policy for biomedical journals increasingly calls on authors to affirm that approval was received from an Institutional Review Board (IRB) (or equivalent) prior to initiating any human subjects research presented in a manuscript submitted for publication. For most investigations and investigators this does not present any problem. However, when research is carried out in a setting where there is no IRB, should editors consider a report of such a study based on the merits alone? There is no simple answer to this question. This commentary explores aspects of the question and presents issues to be considered in developing an answer. Am. J. Ind. Med. 52:172-175, 2009. (c) 2008 Wiley-Liss, Inc.

Previous evidence suggests that severe heat illness may cause permanent acute damage to the heart, kidneys, and liver, which may possibly lead to chronic and even fatal disorders. We investigated whether individuals who had been hospitalized for severe heat illness were at increased risk of cause-specific and total mortality. A cohort mortality study was conducted of male and female US Army personnel hospitalized for heat illness (HI) from 1971 to 2000 using appendicitis (APX) as the reference. Hospitalization records were acquired from the Total Army Injury and Health Outcomes Database (TAIHOD) for 3971 cases of HI and 17,233 APX reference cases. Subject vital status was established through the National Death Index. HI cases had a 40% increased risk of all-cause mortality compared to APX cases. Further examining cause-specific deaths, male cases of HI were at an increased rate of death from cardiovascular disease (CVD) (rate ratio (RR)=1.71, 95% confidence interval (CI): 1.01, 2.89) and ischemic heart disease (IHD) (RR=2.23, 95% CI: 1.02, 4.90) compared to APX reference cases. Our findings provide preliminary evidence for increased risk of mortality among those who have experienced prior hospitalization for heat illness.

The objectives of this study were to document the high rates of acute injuries and physical assaults among nurses and certified nursing assistants working in long-term psychiatric care facilities and to identify risk factors for assaults and injuries to inform prevention strategies. A mixed-design cohort study was conducted. Acute injury and physical assault data were obtained from administrative records. Using staff rosters and schedule records, incidence rates were calculated by job title, gender, shift, and floor. Rates were also reported by severity, body part, type, and nature. Targeted interviews with staff members provided measures of physical lifting and resident combativeness. Injury rates were calculated by degree of lifting and assault rates were calculated by degree of resident combativeness. Overall rates of injuries (55.6 per 100 person-years) and assaults (67.3 per 100 person-years) were substantially higher than expected. Predictably, injuries were associated with resident lifting and assaults were associated with contact with combative residents. A higher risk of assault was found among women and higher risks of injury and assault were observed among full-time employees compared to per diem or pool agency workers. In addition, weekend shifts were found to have a higher rate of injuries and a lower rate of assaults than weekday shifts. In similar longterm care facilities with psychiatric populations, efforts should be made to reduce lifting and avoid circumstances that agitate residents. Work organization factors should be taken into consideration when developing interventions.

In order to evaluate chronic effects of long-term exposure to cotton dust on respiratory health, and the role of dust and endotoxin, longitudinal changes in lung function and respiratory symptoms were observed prospectively from 1981 to 2001 in 447 cotton textile workers, along with 472 silk textile controls. The results from five surveys conducted over the 20-yr period are reported, including standardised questionnaires, pre- and post-shift spirometric measurements, work-area inhalable dust sample collections and airborne Gram-bacterial endotoxin analysis. Cotton workers had more persistent respiratory symptoms and greater annual declines in forced expiratory volume in one second (FEV 1 ) and forced vital capacity as compared with silk workers. After exposure cessation, in the final 5-yr period, the rate of FEV 1 decline tended to slow in nonsmoking males, but not in nonsmoking females. Workers who reported byssinotic symptoms more persistently suffered greater declines in FEV 1 . Chronic loss in lung function was more strongly associated with exposure to endotoxin than to dust. In conclusion, the current study suggests that long-term exposure to cotton dust, in which airborne endotoxin appears to play an important role, results in substantial adverse chronic respiratory effects.

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.

The U.S. Bureau of Labor Statistics and workers' compensation insurers reported dramatic drops in rates of occupational injuries and illnesses during the 1990s. The authors argue that far-reaching changes in the 1980s and 1990s, including the rise of precarious employment, falling wages and opportunities, and the creation of a super-vulnerable population of immigrant workers, probably helped create this apparent trend by preventing employees from reporting some injuries and illnesses. Changes in the health care system, including loss of access to health care for growing numbers of workers and increased obstacles to the use of workers' compensation, compounded these effects by preventing the diagnosis and documentation of some occupational injuries and illnesses. Researchers should examine these forces more closely to better understand trends in occupational health.

Background Both women's and men's occupational health problems merit scientific attention. Researchers need to consider the effect of gender on how occupational health issues are experienced, expressed, defined, and addressed. More serious consideration of gender-related factors will help identify risk factors for both women and men. Methods The authors, who come from a number of disciplines (ergonomics, epidemiology, public health, social medicine, community psychology, economics, sociology) pooled their critiques in order to arrive at the most common and significant problems faced by occupational health researchers who wish to consider gender appropriately. Results This paper describes some ways that gender can be and has been handled in studies of occupational health, as well as some of the consequences. The paper also suggests specific research practices that avoid errors. Obstacles to gender-sensitive practices are considered. Conclusions Although gender-sensitive practices may be difficult to operationalize in some cases, they enrich the scientific quality of research and should lead to better data and ultimately to well-targeted prevention programs. ⌐ 2003 Wiley-Liss, Inc.

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.

To evaluate the chronic effects of exposure to cotton dust, a 15-yr follow-up study in cotton textile workers was performed in Shanghai, China from 1981 to 1996. Testing occurred four times during the 15-yr period. The achieved follow-up rates were 76-88% of the original 447 cotton textile workers, and 70-85% of the original 472 silk textile workers (as a control group). Identical questionnaires, equipment, and methods were used throughout the study. The prevalence of byssinosis increased over time in cotton workers, with 15.3% at the last survey versus 7.6% at the baseline, whereas no byssinosis was found in silk workers. More workers in the cotton group consistently reported symptoms than in the silk group, although symptom reporting varied considerably from survey to survey. Cotton workers had small, but significantly greater, adjusted annual declines in FEV(1) and FVC than did the silk workers. Years worked in cotton mills, high level of exposure to endotoxin, and across-shift drops in FEV(1) were found to be significant determinants for longitudinal change in FEV(1), after controlling for appropriate confounders. Furthermore, there were statistically significant associations between excessive loss of FEV(1) and byssinosis, chest tightness at work, and chronic bronchitis in cotton workers. Workers who consistently (three or four of the surveys) reported byssinosis or chest tightness at work had a significantly greater 15-yr loss of FEV(1). We conclude that long-term exposure to cotton dust is associated with chronic or permanent obstructive impairments. Consistent reporting of respiratory symptoms, including byssinosis and chest tightness at work, is of value to predict the magnitude and severity of chronic impairments in textile workers.

Background Several researchers have proposed fiber size ranges representing hypotheses about the biological activity of fibers. Each of these indices has a biologically plausible rationale, yet they propose different fiber dimensions. Methods Four biologically based and one standard fiber analytic method index, the NIOSH 7400 method with B rules, were evaluated in air monitoring data collected in a variety of fiber glass (FG) manufacturing settings to determine their impact on an assessment of fiber exposure for an epidemiologic study of the risk of respiratory cancer among FG production workers. Results All indices varied considerably within and among the range of fiber size distributions sampled in the FG factories. Conclusions The asymptotic relative efficiencies (R 2 ) calculated among the five indices indicate a potentially important loss of power from the use of the standard method index, if one of the biologically based indices is more closely related to the disease outcome in an epidemiologic study.

This study examines the determinants of susceptibility to the irritant effects of sodium borate in 18 responsive workers identified through repeated self-reports of nasal irritation. For each worker, susceptibility was characterized by two features; reactivity and sensitivity, as estimated from the slope and intercept parameters from their individual exposure-response regression model. Individual estimates of reactivity and sensitivity were then examined to evaluate the importance of personal and environmental characteristics in determining susceptibility. The use of nasal sprays, current smoking and allergies were associated with lower reactivity, while high exposures to borate dust were associated with higher sensitivity. To examine possible biologic mechanisms for the irritant response, a toxicokinetic dose model was used to calculate nasal osmolarity during symptom intervals. The estimated levels suggest that osmolar activation of mast cells to release histamine and other mediators is a plausible mechanism by which these workers may experience nasal irritation.

Background Results are reported from a nested case-control study of 60 esophageal cancer deaths among 46,384 automobile manufacturing workers potentially exposed to metalworking fluids (MWF) in machining and grinding operations. Methods By using incidence-density sampling, controls were selected with a sampling ratio of 20:1 from among co-workers who remained at risk by the age of death of the case, matched on race, gender, plant, and year of birth. Conditional logistic regression was used to evaluate the risk associated with cumulative exposure (mg/m3-years) to each of three types of metalworking fluid (straight, soluble, and synthetic MWF), as well as with years of exposure to selected components of MWF, including nitrosamines, sulfur, biocides, and several metals. Results Esophageal cancer was found to be significantly associated with exposure to both soluble and synthetic MWF in grinding operations. The odds ratios (ORs) for grinding with soluble MWF were elevated at 2.5 or greater in all categories of cumulative exposure, although the exposure-response trend was statistically significant only when exposure was measured as duration. Those with 12 or more years exposure to soluble MWF in grinding operations experienced a 9.3-fold relative risk of esophageal cancer mortality (95% CI = 2.1–42.1). The OR for ever grinding with synthetic MWF was 4.1 (95% CI = 1.1–15.0). Elevated risk was also associated with two agents found in both synthetic and soluble fluids, nitrosamines, and biocides. For exposure to nitrosamines, the OR was 5.4 (95% CI = 1.5–19.9); for biocides the OR was 3.8 (95% CI = 0.8–18.9). However, because the same workers were exposed to grinding with synthetics, nitrosamines and biocides, it was not possible to separate the specific risks associated with these components. Am. J. Ind. Med. 34:36–48, 1998. © 1998 Wiley-Liss, Inc.

Here we address a general issue raised by questions about the "Persian Gulf syndrome" and toxic exposure to troops engaged in the Persian Gulf War: where and how does a new category of illness or disease become established, and how can that process be improved? Persian Gulf War veterans have reported health problems that many suggest are related to service in that war during the period 1990-1991. A variety of complaints have been recorded by health care providers throughout the country, but, for the most part, these have not resulted in a clear diagnosis or explanation except for a very small number of complaints which have led to clear diagnoses such as leishmaniasis or malaria. Several distinguished review panels have examined the evidence that service in the Gulf is related to alleged chronic health problems (1-6). While these reviews have caused participants to be impressed and concerned about the veterans' complaints, no review panel has arrived at a definitive understanding of the veterans' illnesses. The review panels generally agree that there is unlikely to be a single explanation for the veterans' complaints. Consequently, health scientists supported by both private and public funds have been engaged in laboratory, clinical, and epidemiologic studies to find the cause or causes of the illnesses. Stress related to war, historically associated with health problems (7), as well as particular features of the Gulf War (major involvement of reserve troops, first major conflict with a volunteer force, substantial number of women soldiers) have been regularly cited as important contributors to complaints and disability among Gulf War veterans. An unknown number of