Animal data and physical models suggest that the carcinogenicity of asbestos fibres is related to their size and shape.
To investigate the influence of fibre length and diameter on lung cancer risk in workers at asbestos textile mills in North Carolina and South Carolina, USA.
Men and women (n=6136) who worked ≥30 days in production and were employed between 1940 and 1973 were enumerated and followed for vital status through 2003. A matrix of fibre size-specific exposure estimates was constructed using determinations of fibre numbers and dimensions through analysis of 160 historical dust samples by transmission electron microscopy. Associations of lung cancer mortality with metrics of fibre exposure were estimated by Poisson regression with adjustment for age, sex, race and calendar year.
Exposure to fibres throughout the range of length and diameter was significantly associated with increased risk of lung cancer. Models for fibres >5 μm long and <0.25 μm in diameter provided the best fit to the data, while fibres 5–10 μm long and <0.25 μm in diameter were associated most strongly with lung cancer mortality (log rate about 4% per IQR, p<0.001). When indicators of mean fibre length and diameter were modelled simultaneously, lung cancer risk increased as fibre length increased and diameter decreased.
The findings support the hypothesis that the occurrence of lung cancer is associated most strongly with exposure to long thin asbestos fibres. The relationship of cancer risk and fibre dimensions should be examined in cohorts exposed to other types of fibres.
To quantify the life years gained and financial savings by preventing a case of occupational cancer.
The authors retrieved data from the Taiwan Cancer Registry and linked them with the National Mortality Registry to estimate the survival functions for major occupational cancers: lung, pleural mesothelioma, urinary bladder and leukaemia. Assuming a constant excess hazard for each type of cancer, the authors extrapolated lifetime survival functions by the Monte Carlo method. For each patient with cancer, the authors simulated an age- and gender-matched person without cancer based on vital statistics of Taiwan to estimate life expectancy and expected years of life lost (EYLL). By using the reimbursement data from the National Health Insurance Research Database, the authors calculated the average monthly healthcare expenditures, which were summed to estimate the lifetime healthcare expenditures after adjusting for the corresponding monthly survival probability.
A total of 51 408, 136, 12 891 and 5285 new cases of lung, pleural mesothelioma, bladder and leukaemia cancers, respectively, were identified during 1997–2005 and followed until the end of 2007. The EYLL was predicted to be 13.7±0.1, 18.9±0.7, 4.7±0.3 and 19.4±0.5 years for these cancers, respectively, and the lifetime healthcare expenditures with a 3% annual discount were predicted to be US$22 359, US$14 900, US$51 987 and US$59 741, respectively.
The burden of these occupational cancers, in terms of EYLL and lifetime healthcare expenditures, was substantial. Such estimates may provide useful empirical evidence for comparative risk assessment that can be applied in health policy-making and clinical decision-making.
Observational studies suggest that high job strain is a risk factor for retirement on health grounds, but few studies have analysed specific diagnoses. We examined job strain's association with all-cause and cause-specific disability pensions.
Survey responses to questions about job strain from 48 598 (response rate, 68%) public sector employees in Finland from 2000 to 2002 were used to determine work unit- and occupation-based scores. These job strain scores were assigned to all the 69 842 employees in the same work units or occupations. All participants were linked to the disability pension register of the Finnish Centre of Pensions with no loss to follow-up. Cox proportional hazard models were used to calculate HRs and their 95% CIs for disability pensions adjusted by demographic, work unit characteristics and baseline health in analyses stratified by sex and socioeconomic position.
During a mean follow-up of 4.6 years, 2572 participants (4%) were granted a disability pension. A one-unit increase in job strain was associated with a 1.3- to 2.4-fold risk of requiring a disability pension due to musculoskeletal diseases in men, women and manual workers, depending on the measure of job strain (work unit or occupation based). The risk of disability pension due to cardiovascular diseases was increased in men with high job strain but not in women nor in any socioeconomic group. No consistent pattern was found for disability pension due to depression.
High job strain is a risk factor for disability pension due to musculoskeletal diseases.
We have thus explored the clinical usefulness of the QSAR model in relation to a clinical case.
We evaluated a 42 years old atopic male wood worker exposed to different wood...]]>
Bisphenol A (BPA) is widely used in epoxy resins in China. There are few reports on the adverse health effects of occupational exposure to BPA. This study examined associations between urinary BPA concentrations in workers and laboratory parameters for health status.
Spot urine checks at the end shift on Friday were used for cross-sectional analysis of BPA concentrations, and blood or urinary markers of liver function, glucose homeostasis, thyroid function and cardiovascular diseases were measured. The 28 participants were workers in two semiautomatic epoxy resin factories.
The average urinary BPA concentration was 55.73±5.48 ng/ml (geometric mean ± geometric SD) (range 5.56–1934.85 ng/ml). After adjusting for urine creatinine (Cr), it was 31.96±4.42 μg/g Cr (geometric mean ± geometric SD) (range 4.61–1253.69 μg/g Cr). BPA feeding operators showed the highest concentrations, over 10 times those of the crushing and packing and office workers. Higher BPA concentrations were associated with clinically abnormal concentrations of FT3, FT4, TT3, TT4, thyroid-stimulating hormone, glutamic-oxaloacetic transaminase and -glutamyl transferase. Workers with higher BPA concentrations showed higher FT3 concentrations (linear trend: p<0.001). Bivariate correlation tests for laboratory analytes within normal limits showed FT3 to be positively associated with logged BPA concentrations, r=0.57, p=0.002. FT4 was positively associated with lactate dehydrogenase, r=0.45, p=0.020, and insulin was positively associated with thyroid-stimulating hormone with r=0.57, p=0.009.
Higher occupational BPA exposure, reflected in urinary concentrations of BPA, may be associated with thyroid hormone disruption.
To assess livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) carriage among workers in pig slaughterhouses and assess associated risk factors, including occupational exposure to LA-MRSA.
A cross-sectional study in three Dutch pig slaughterhouses was undertaken. Nasal swabs of participants were taken. Nasal swabs and surface wipes, air and glove samples were screened for presence of methicillin-resistant Staphylococcus aureus (MRSA). MRSA was quantitatively determined on gloves and in air samples by culturing and real-time PCR.
11 of 341 (3.2%) participants were identified as nasal MRSA carriers. MRSA-positive workers were predominantly found at the start of the slaughter process. Major risk factors for carriage were working in the lairage and working in the scalding and dehairing area. Most nasal isolates (73%) belonged to the LA-MRSA clone ST398. MRSA ST398-positive environmental samples were found throughout the slaughter process. A clear decrease was seen along the slaughterline in the number of MRSA-positive samples and in the MRSA amount per sample.
This study showed that working in the lairage area or scalding and dehairing area were the major risk factors for MRSA carriage in pig slaughterhouse workers, while the overall prevalence of MRSA carriage is low. Occupational exposure to MRSA decreased along the slaughterline, and the risk of carriage showed a parallel decrease.
As part of smoking surveillance, the authors conducted an epidemiologic investigation in southern Brazil to identify the occurrence of Green Tobacco Sickness and risk factors for illness and to recommend control and prevention measures.
A 1:2 case–control study matched by subjects' smoking habits. The study population was residents of Candelária, Rio Grande do Sul state, who farm tobacco and provided a urine sample for cotinine measurement by high-performance liquid chromatography. Confirmed cases were persons with compatible clinical presentation (headache, nausea, vomit, dizziness or weakness) and cotinine level >10 ng/ml. Controls were persons without compatible signs or symptoms. The association measure was the matched OR with 95% CIs and p<0.05.
Of 33 confirmed cases, 64% were men, average age was 33 years (SD ±11.8 years) and 57% were landowners. Cases have had similar illness in the past and were likelier to be workers hired by farmers–landowners than controls. Multivariate analysis yielded independent association between these variables and illness, controlled for age and sex. Contact with pesticides and working with wet tobacco leaves were not associated with illness.
The authors confirmed Green Tobacco Sickness in southern Brazil; the authors recommend investigation of its prevalence in tobacco-growing regions and monitoring of and education about the disease and its prevention by occupational health authorities.
Critically shortening of telomere length caused by various factors including environmental pollutants results in genome instability and age-associated diseases. Lead is one of the ubiquitous environmental and occupational pollutants, potentially affecting public health even at a low level. However, it is still unclear whether lead exposure affects telomere length. This study aims to investigate the association between lead exposure and peripheral white blood cell telomere length (PWBTL) in Chinese battery manufacturing plant workers.
Lead levels in blood (BLL) and urine (ULL) were evaluated using flame atomic absorption spectrometry and lead mobilisation test for body lead burden (BLB) assessment, respectively. Quantitative PCR was employed to determine relative PWBTL. Univariate and multivariate analyses were performed to examine the associations of telomere length and other variables.
PWBTL averaged 1.76 (telomere/single-copy gene of albumin, T/S) in 144 battery plant workers. Significantly shorter PWBTL was observed in the workers with abnormal BLL and/or ULL than those with normal ones (1.66±0.63 vs 1.91±0.46, p=0.010). In all workers, PWBTL was in negative correlations with BLL, ULL, time working at the plant (working length) and body mass index. A strong inverse correlation was observed between PWBTL and BLB (r=–0.70, p<0.0001) in those with abnormal BLL and ULL. GLMSELECT model showed in the subgroup of inpatient workers, working length and BLB were significantly in inverse associations with PWBTL, while BLL was in weak positive association with PWBTL.
These findings suggest that PWBTL shortening is associated with long-term lead exposure and that PWBTL may be one of the targets damaged by lead toxicity.
The aim of this prospective study was to examine the role of physical workload, leisure-time physical activity, obesity and smoking in predicting the occurrence and course of multisite musculoskeletal pain (MSP).
Data on physical and psychosocial workload, lifestyle factors and MSP were based on questionnaire surveys of 385 Finnish female kitchen workers. MSP (defined as pain at three or more of seven sites) during the past 3 months was measured repeatedly at 3-month intervals over 2 years. Four different patterns (trajectories) in the course of MSP were identified. The authors analysed whether the determinants at baseline predicted the occurrence of MSP (1) at the 2-year follow-up and (2) over the total of nine measurements during the 2 years by exploiting the MSP trajectories. Logistic regression was used.
High physical workload at baseline was an independent predictor of MSP at the 2-year follow-up (OR 3.8, 95% CI 1.7 to 8.5) in a model allowing for age, psychosocial factors at work and lifestyle. High physical workload (OR 2.0, 95% CI 1.0 to 4.0) and moderate (OR 2.4, 95% CI 1.2 to 4.9) or low (OR 2.3, 95% CI 1.1 to 4.7) physical activity predicted persistent MSP. Obesity (OR 2.8, 95% CI 1.0 to 7.8) predicted an increased, and not being obese (OR 3.7, 95% CI 1.1 to 12.7) a decreased, prevalence of MSP in models similarly including all covariates. Smoking had no effect.
The results emphasise the importance of high physical workload, low to moderate physical activity and obesity as potential modifiable risk factors for the occurrence and course of MSP over time.
Fishermen who had participated in clean-up activities of the Prestige oil spill showed an excess risk of respiratory symptoms 1–2 years later, but the long-term persistence of these health effects is unclear. The aim of this study was to evaluate the persistence of these respiratory symptoms 5 years after clean-up work.
Subgroups of 501 fishermen who had been exposed to clean-up work and 177 non-exposed individuals were re-interviewed by telephone in 2008, including the same symptom questions as in the initial survey. Associations between participation in clean-up work and respiratory symptoms were assessed using log-binomial and multinomial regression analyses adjusting for sex, age and smoking.
Information from 466 exposed (93%) and 156 non-exposed (88%) fishermen was obtained. The prevalence of lower respiratory tract symptoms (including wheeze, shortness of breath, cough and phlegm) had slightly decreased in both groups, but remained higher among the exposed (RR 1.4, 95% CI 1.1 to 1.9). The risk of having persistent respiratory symptoms (reported both at baseline and at follow-up) increased with the degree of exposure: RR ratio 1.7 (95% CI 0.9 to 3.1) and 3.3 (95% CI 1.8 to 6.2) for moderately and highly exposed, respectively, when compared with those without any symptoms. Findings for nasal symptoms and for respiratory medication usage were similar.
Participation in clean-up activities of oil spills may result in respiratory symptoms that persist up to 5 years after exposure. Guidelines for preventive measures and a continued surveillance of clean-up workers of oil spills are necessary.
The case definition was discussed among several research groups in USA who have met for several years to discuss such issues as part of a musculoskeletal disorder research consortium. Although each institution has carried out independent research, and their case definitions for CTS are not identical, all agreed that the components would include nerve conduction testing and symptoms recorded on hand diagrams, but not physical examination findings. In...]]>
Fukushima Dai-ichi nuclear power plant (NPP) was heavily damaged by the tsunami that resulted from the 9.0-magnitude earthquake which occurred off the coast of eastern Japan on 11 March 2011.
Efforts were made to achieve stable cooling of the nuclear reactors, and the release of radioactive materials was brought under control. On 16 December 2011, the Japanese government, the Tokyo Electric Power Company (TEPCO) and technical-support companies achieved cold shutdown of all the reactors stricken by the tsunami. During this period, numerous efforts were made to protect...]]>
Their first and highly relevant question is about the magnitude of the annual decline of forced expiratory volume in one second (FEV1) denoted as dFEV1 among workers with FEV1/forced vital capacity (FVC) ratio <0.7 and lower limit of normal (LLN) compared with dFEV1 among workers with FEV1/FVC ratio ≥ LLN and <0.7. In the former group dFEV1 = –58.4 ml/year, whereas in the latter group dFEV1 = –57.4 ml/year, that is the difference between these two groups was negligible (p=0.94).
In clinical settings we find it well justified to use FEV1/FVC <0.7 as a screening limit in occupational healthcare.
We also have some principal aspects that have to be addressed.
Generally, we believe that diseases should be defined by morphological characteristics. However, it is not feasible to diagnose chronic obstructive pulmonary disease...]]>
Retrospective exposure assessment in population-based case–control studies poses a major challenge due to the wide range of occupations and industries involved. The FINJEM is a generic job-exposure matrix (JEM) developed in Finland, which represents a potentially cost-effective exposure assessment tool. While FINJEM has been used in several studies outside Finland, little is known of its applicability in other countries.
We compared prevalence and intensity of exposure in FINJEM with a JEM developed from expert assessments of occupational histories obtained in a population-based case–control study in Montreal. Agreement for prevalence of exposure was measured by weighted coefficients between prevalence categories. Agreement for exposure intensity was measured by Spearman correlation coefficients between cells with non-null exposure.
The comparison involved 27 chemicals, the time period 1945–1995 and included 4743 jobs initially assessed by the Montreal experts. 4293 combinations of agent, occupational title and period were available for comparison of prevalence. Agent-specific prevalence was consistently higher in the Montreal JEM (median difference 1.7%). Agent-specific values between prevalence categories varied from 0.89 (welding fumes) to 0.07 (flour dust). The comparison of exposure levels involved 14 agents and 198 cells with non-null exposure in both sources. Agent-specific Spearman correlation varied from 0.89 (flour dust) to –0.35 (benzo(a)pyrene).
Our observations suggest that information concerning several agents (eg, metals, welding fumes) can be successfully transported from Finland to Canada and probably other countries. However, for other agents, there was considerable disagreement, and hence, transportability of FINJEM cannot be assumed by default.
The authors had a unique opportunity to study the early impacts of occupational and recreational exposures on the development of noise-induced hearing loss (NIHL) in a cohort of 392 young workers. The objectives of this study were to estimate strength of associations between occupational and recreational exposures and occurrence of early-stage NIHL and to determine the extent to which relationships between specific noise exposures and early-stage NIHL were mitigated through the use of hearing protection.
Participants were young adults who agreed to participate in a follow-up of a randomised controlled trial. While the follow-up study was designed to observe long-term effects (up to 16 years) of a hearing conservation intervention for high school students, it also provided opportunity to study the potential aetiology of NIHL in this worker cohort. Study data were collected via exposure history questionnaires and clinical audiometric examinations.
Over the 16-year study period, the authors documented changes to hearing acuity that exceeded 15 dB at high frequencies in 42.8% of men and 27.7% of women. Analyses of risk factors for NIHL were limited to men, who comprised 68% of the cohort, and showed that risks increased in association with higher levels of the most common recreational and occupational noise sources, as well as chemical exposures with ototoxic potential. Use of hearing protection and other safety measures, although not universal and sometimes modest, appeared to offer some protection.
Early-stage NIHL can be detected in young workers by measuring high-frequency changes in hearing acuity. Hearing conservation programmes should focus on a broader range of exposures, whether in occupational or non-occupational settings. Priority exposures include gunshots, chainsaws, power tools, smoking and potentially some chemical exposures.
Though toxicological experiments demonstrate the teratogenicity of organic solvents in animal models, epidemiologic studies have reported inconsistent results. Using data from the population-based National Birth Defects Prevention Study, the authors examined the relation between maternal occupational exposure to aromatic solvents, chlorinated solvents and Stoddard solvent during early pregnancy and neural tube defects (NTDs) and orofacial clefts (OFCs).
Cases of NTDs (anencephaly, spina bifida and encephalocoele) and OFCs (cleft lip ± cleft palate and cleft palate alone) delivered between 1997 and 2002 were identified by birth defect surveillance registries in eight states; non-malformed control infants were selected using birth certificates or hospital records. Maternal solvent exposure was estimated by industrial hygienist review of self-reported occupational histories in combination with a literature-derived exposure database. ORs and 95% CIs for the association between solvent class and each birth defect group and component phenotype were estimated using multivariable logistic regression, adjusting for maternal age, race/ethnicity, education, pre-pregnancy body mass index, folic acid supplement use and smoking.
The prevalence of exposure to any solvent among mothers of NTD cases (n=511), OFC cases (n=1163) and controls (n=2977) was 13.1%, 9.6% and 8.2%, respectively. Exposure to chlorinated solvents was associated with increased odds of NTDs (OR=1.96, CI 1.34 to 2.87), especially spina bifida (OR=2.26, CI 1.44 to 3.53). No solvent class was strongly associated with OFCs in these data.
The findings suggest that maternal occupational exposure to chlorinated solvents during early pregnancy is positively associated with the prevalence of NTDs in offspring.
To compare the yield of hand-searching with optimised electronic search strategies in retrieving occupational health (OH) intervention studies published in a language other than English.
The authors systematically hand-searched and screened reports of OH intervention studies published in Italian in peer-reviewed scientific journals between 1990 and 2008. The authors evaluated how many of them met the Cochrane Occupational Safety and Health Review Groups (OSHRG) definition of being an OH intervention study and how many potentially relevant studies retrieved by hand-searching would not be found by PubMed alone using the OSHRG's most specific and most sensitive search strings.
Hand-searching retrieved 25 articles (reporting 27 studies), including nine not indexed in MEDLINE. Most studies (81%, 22/27) had a before–after design and only one was a randomised trial. The OSHRG's most sensitive search string retrieved all 16 articles published in the Italian language journals that were indexed in MEDLINE, while the most specific search strategy retrieved nine articles (56%, 9/16). The most specific search string showed a lower ‘number needed to read’ value than the most sensitive one (60 vs 132).
These findings suggest that a sensitive electronic search strategy may be able to find most of the OH interventions published in languages other than English that are indexed in MEDLINE. Hand-searching of important national journals not indexed in MEDLINE should be considered when conducting particularly in-depth research.
In the mid-1990s, a general hypothesis was launched linking inhalation of particles to the occurrence of IHD in urban as well as working environments by an inflammatory pathway associated with increased blood coagulation. In 2010, the American Heart Association concluded strong epidemiological evidence of a relation between short-term (days) or long-term exposure (months to years) to PM2.5 (fine particulate matter) urban air pollutants and the occurrence of IHD. Today, studies indicate strong overall mechanistic evidence for a systemic inflammatory response as an intermediary pathway between inhalation of particles and IHD.
Chronic beryllium exposure may stimulate the acquired immune response to release mediators of chronic inflammation in...]]>
To evaluate the effectiveness of a draft occupational health practice guideline aimed at preventing weight gain on employees' physical activity, sedentary behaviour and dietary behaviour and on body weight-related outcomes.
A randomised controlled trial was performed comparing guideline-based care to usual care among 16 occupational physicians and 523 employees in the Netherlands between 2009 and 2011. Occupational physicians in the intervention group followed the draft guideline by providing advice to employers on how to assess and intervene on the obesogenic work environment and conducted five face-to-face behavioural change counselling sessions with employees to improve their lifestyle. Data of employees were collected by questionnaire and physical measurements at baseline and 6-months follow-up. Linear and logistic regression analyses were performed to determine effects.
The intervention showed significant effects on sedentary behaviour at work (β –28 min/day, 95% CI –2 to –54) and on fruit intake (β 2.1 pieces/week; 95% CI 0.6 to 3.6). No significant intervention effects were found for physical activity, sedentary behaviour in leisure time or during weekend days, snack intake and body weight-related outcomes.
Guideline-based care resulted in a more favourable sedentary behaviour at work and increased fruit intake but did not improve employees' physical activity, snack intake or body weight-related outcomes.
ISRCTN/73545254 and NTR/1190.
Regarding differences in associations with musculoskeletal disorders observed across studies using self-reported estimates of computer use versus memory resident software documentation of computer use we made no argument that one was correct and the...]]>
To report the annual incidence of occupational diseases (ODs) in economic sectors in The Netherlands.
In a 5-year prospective cohort study (2009–2013), occupational physicians were asked to participate in a sentinel surveillance system for OD notification. The inclusion criteria for participation were (1) covering a population of employees, (2) reporting the economic sectors and the size of their employee population and (3) willingness to report all diagnosed ODs. In this study, an OD was defined as a disease with a specific clinical diagnosis that was predominantly caused by work-related factors. The economic sectors (n=21) were defined according the NACE (Nomenclature des Activités Économiques dans la Communauté Européenne) classification.
In a total working population of 514 590 employees, 1782 ODs were reported over 12 months in 2009. The estimated annual incidence for any OD was 346 (95% CI 330 to 362) per 100 000 worker-years. Of all the ODs, mental diseases were reported most frequently (41%), followed by musculoskeletal (39%), hearing (11%), infectious (4%), skin (3%), neurological (2%) and respiratory (2%) diseases. The four economic sectors with the highest annual incidences per 100 000 workers were construction (1127; 95% CI 1002 to 1253), mining and quarrying (888; 95% CI 110 to 1667), water and waste processing (832; 95% CI 518 to 1146) and transport and storage (608; 95% CI 526 to 690).
ODs are reported in all economic sectors in The Netherlands. Up to 91% of all ODs are mental, musculoskeletal and hearing diseases. Efforts to increase the effective assessment of ODs and compliance in reporting activities enhance the usability of incidence figures for the government, employers and workers.
Ferrario et al investigated the effect of occupational class on the incidence of coronary heart disease by a 12-year follow-up study and concluded that higher HRs of coronary heart disease incidence rates were observed in manual workers, professionals and administrators, and self-employed workers compared with non-manual workers adjusted by age.
Mergers and acquisitions (M&A) activities are increasing and may negatively affect workers mental health. However, the impact of M&A on the risk of developing a mental disorder, rather than psychiatric symptoms, has not been investigated. The objectives of this study were to estimate and compare the 12-month incidence of depressive and anxiety disorders in workers who had and who had not experienced M&A in the last year.
Employees aged 25 and 64 years old were randomly selected from the community and were followed for 1 year (n=3280). Questions about their experience in M&A in the past 12 months were asked. WHO's Composite International Diagnostic Interview–Auto 2.1 was used to assess depressive and anxiety disorders. The 12-month prevalence and 1-year incidence of mental disorders were estimated and compared in relation to M&A.
Participants who were exposed to M&A had a significant higher 1-year incidence of generalised anxiety disorder (GAD) (6.7%) than the unexposed (2.4%). They were not different in the incidence of major depressive disorder. The exposed participants were 2.8 times more likely to have had a GAD than others and were about 2.4 times more likely to have developed any anxiety disorders over 1 year.
M&A may lead to increased risk of GAD, which may, in return, evolve into major depression. Governments, employers and health professionals should be aware of this and work out plans to reduce the negative health outcomes of M&A.
Idiopathic oSCC is not uncommon, but when it occurs in a husband and wife who worked in, and lived above, their own dry cleaning business, an active dry cleaning agent must be considered as the potential aetiological factor.
A 65-year-old man presented with a 6-month history of dyspepsia and epigastric pain without dysphagia or weight loss. He owned a dry cleaning shop and lived in the same premises for 30 years. He smoked a pipe for 35 years. Upper gastrointestinal endoscopy showed an oesophageal tumour at 33 cm, and staging CT confirmed lower oesophageal tumour without evidence of lymphadenopathy or distant metastasis. He underwent transhiatal oesophagectomy and the final...]]>