Occupational Exposure Groups Research Articles

Effects of Occupational Noise Exposure on Hearing Loss: Regulatory Effect of Mediterranean Diet.

To assess regulatory effect of Mediterranean diet for occupational noise exposure and hearing loss. Methods: This cross-sectional study included 4757 individuals. Weighted logistic regression model was adopted to explore the association of occupational noise exposure and Mediterranean diet with hearing loss, and regulatory effects of the Mediterranean diet for the relationship of occupational noise exposure and hearing loss. Results: Occupational noise exposure was associated with an increased odds of hearing loss. Under low adherence to the Mediterranean diet, the occupational noise exposure group was related to increased odds of hearing loss. Under high adherence to the Mediterranean diet, no significant difference was observed between occupational noise exposure and hearing loss, and adjusted effect size was reduced accordingly. Conclusion: Mediterranean diet may moderate this relationship of occupational noise exposure and hearing loss to some degree.

Occupational exposure to vapors, gasses, dusts, and fumes in relation to causes of death during 24 years in Helsinki, Finland

PurposeEnvironmental particulate matter (PM) exposure has been shown to cause excess all-cause and disease-specific mortality. Our aim was to compare disease-specific mortality by estimated occupational exposure to vapors, gasses, dusts, and fumes (VGDF).MethodsThe data source is the Helsinki part of the population-based FinEsS study on chronic obstructive pulmonary diseases including information on age, education level, main occupation, sex, and tobacco smoking combined with death registry information. We compared estimated VGDF exposure to mortality using adjusted competing-risks regression for disease-specific survival analysis for a 24-year follow-up.ResultsCompared to the no-exposure group, the high occupational VGDF exposure group had sub-hazard ratios (sHR) of 1.7 (95% CI 1.3–2.2) for all cardiovascular-related and sHR 2.1 (1.5–3.9) for just coronary artery-related mortality. It also had sHR 1.7 (1.0–2.8) for Alzheimer’s or vascular dementia-related mortality and sHR 1.7(1.2–2.4) for all respiratory disease-related mortality.ConclusionLong-term occupational exposure to VGDF increased the hazard of mortality- to cardiovascular-, respiratory-, and dementia-related causes. This emphasizes the need for minimizing occupational long-term respiratory exposure to dust, gasses, and fumes.

Occupational Risk Factors by Sectors: An Observational Study of 20,000 Workers.

We aimed to assess the prevalence of exposure by sector and the sectors of activity most exposed to each exposure, using routine occupational health data, and to quantify the risk of being exposed. Occupational risk factors were assessed by workers followed by the Occupational Health Service of Cher, using self-reported questionnaires. The sectors of activity were grouped into seven sectors, and the risks were grouped into six occupational exposure groups. Comparisons were made using the Chi-squared test and Cramer's V, and the odds ratios were calculated by using logistic regression. We included 19,891 workers. The construction sector had the highest prevalence (p < 0.05 vs. all other sectors) of exposure to physical (76%) and biomechanical factors (82%), as well as chemical risks (75%). Human health and social work was the sector with the highest prevalence of exposure to biological factors (69%), psychosocial factors (90%), and atypical working hours (61%). With workers from administrative and support sectors as the reference, construction workers had more chance of declaring exposure to physical factors (OR = 3.28, 95%CI = 2.89 to 3.72), biomechanical factors (1.82, 1.58 to 2.09), and chemical agents (3.83, 3.38 to 4.33). Workers from the human health and social sectors had more chance of being exposed to biological agents (13.4, 11.9 to 15.2), atypical working hours (1.93, 1.75 to 2.14), and psychosocial factors (2.74, 2.38 to 3.16). Psychosocial risk factors were commonly reported in all sectors. Workers in the construction, human health, and social sectors seem to report more exposures than those in other sectors. The analysis of occupational exposures is a necessary basis to build an efficient preventive strategy for occupational health.

Exposure to occupational risk factors is associated with the severity and progression of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) results from a complex interaction between genes and the environment, and occupational exposures are an underappreciated risk factor. Until now, little research attention has been paid to the potential impact of occupational risk factor exposure on the COPD in China. The aim of this retrospective study was to analyze the role of occupational risk factor exposure on the severity and progression of COPD for exploring new prevention strategies for this disease. This study adopted a random cluster-sampling method. Five grade-A tertiary hospitals that met the inclusion criteria were selected as the survey sites, and patients with COPD hospitalized in these hospitals from January 1, 2019, to December 31, 2019, were selected as the research subjects. Data of the patients diagnosed with COPD met the Global Initiative for Chronic Obstructive Lung Disease (2019) criteria and were collected from the computerized medical record databases. Among 4082 investigated COPD patients, 1063 (26%) were found to have occupational risk factor exposure history. The top 3 industries with a large COPD case number and a history of occupational risk factor exposure ranked in the order of agriculture (including farming, forestry, animal husbandry, and fishery), manufacturing, and mining. Further multivariate logistic regression analysis indicated that when setting a low exposure level as a reference, medium and high exposure levels were correlated with the severity of COPD (odds ratio values were 2.837 and 6.201, respectively, P < .05). Linear regression analysis showed that cumulative exposure to occupational risk factors was negatively correlated with the forced expiratory volume in 1-second percentage of COPD patients, with a correlation coefficient of 0.68. Our results indicated that occupational risk factor exposure levels were related to the severity of COPD significantly. The incubation period of COPD in the exposure group was significantly shorter than that in the non-exposure group. To prevent worked-related COPD, special attention and control efforts should be taken to reduce the level of occupational risk factors such as organic dust, irritating chemicals, etc in the work environments, especially in the industries of agriculture, forestry, animal husbandry and fishery, manufacturing, and mining.

Association between Occupational Noise Exposure and Insomnia among Night-Shift Production Workers: A 4-Year Follow-up Study.

This study aimed to investigate whether occupational noise exposure is a risk factor for insomnia among male night-shift production workers. This study followed 623 male night-shift production workers at a tire manufacturing factory without insomnia for 4 years. Insomnia was evaluated based on the insomnia severity index at baseline and at 4-year follow-up. A score of ≥15 was defined as insomnia. The higher occupational noise exposure group was defined as those individuals exposed to 8-hour time-weighted-average noise above 80 dB (A). Participants' mean age was 46.3 ± 5.6 years. Of the 623 participants, 362 (58.1%) were in the higher occupational noise exposure group. At 4-year follow-up, insomnia occurred in 3.2% (n = 20) of the participants. In a multiple logistic regression analysis, the odds ratio of insomnia was 3.36 (95% confidence interval 1.083-10.405, P = 0.036) in the higher occupational noise exposure group when compared with the lower noise exposure group after adjusting for confounders. Our findings suggested that occupational noise exposure affected insomnia in male night-shift production workers. To prevent insomnia, efforts are required to reduce workplace noise exposure levels. Alternatively, moving to a less noisy work environment should be considered for workers with severe insomnia.

Expression level and function analysis of serum miRNAs in workers with occupational exposure to benzene series

Benzene series are ubiquitous in industrial production and daily life, and can have an impact on health even at low concentrations. miRNAs have been proved to be a biomarker of a variety of diseases and carcinogens. The purpose of this study was to explore the distribution characteristics and biological function of miRNAs in subjects exposed to benzene series. In this study, serum miRNAs were measured in 247 occupationally exposed subjects and 256 controls. The relationship between cumulative exposure dose of benzene series and miRNAs was analyzed by Generalized linear model, Spearman's rank correlation, and chi-square test for trend. The function of MiRNAs target gene was analyzed by means of bioinformatics method. The results showed that the expressions of miR-181a-5p, 221-3p, 223-3p, and 342-3p were down-regulated, whilst the expression of miR-638 was up-regulated in the occupational exposure group. miR-181a-5p, 221-3p, 223-3p, 342-3p, and 638 showed dose-response relationship with benzene series, and were closely related to multiple tumor pathways. miR-181a-5p, 221-3p, 223-3p, 342-3p, and 638 may be involved in the carcinogenic process of benzene series, and can be used to evaluate the early biological effects and monitor the exposure level of benzene series. miRNAs are potential biomarkers of benzene series exposure.

Assessment of multi-chemical exposure using human biomonitoring data from the French Esteban study using exposure load method.

Exposure to chemical substances is common and comes from several sources (environmental, food, and occupational). It is often studied using a substance-by-substance approach. Although this method helps identify the determinants of exposure to a single chemical, it cannot accurately reflect exposure to multiple chemicals. In this study, we used the concept of exposure load (EL) to evaluate multi-chemical exposure in a representative sample of the general French population. EL corresponds to the number of substances (or metabolites) measured in body fluids above a defined concentration threshold. EL was calculated for adults and children separately for two groups of substances: those currently found in domestic environments (Group A) and pesticides (Group B). Although the EL does not assess the health impact linked to multi-chemical exposure, it does aid in the identification of particularly vulnerable populations. Accordingly, preventive actions specifically aimed at these subgroups could be useful. In Group A, we found that multi-chemical exposure was generalized since all the adults and children had an EL greater than or equal to 13 (out of 22 substances studied) when the LOQ (limit of quantification) was considered as the discretization threshold. In adults, men, smokers and people of working age (i.e., people under 60 years old) had a higher EL. In Group B, multi-chemical exposure was also generalized, since all the adults (15 substances studied) and children (13 substances studied) had a mean EL almost equal to 6 when the LOQ was considered as the discretization threshold. In adults, persons with occupational exposure to pesticide dust had a higher EL when the P90 was considered as the discretization threshold. This study highlights widespread multi-chemical exposure in adults and children in France, and the major impact of occupational exposure (Group B) and tobacco smoking (Group A) on EL.

Brazilian workers occupationally exposed to different toxic agents: A systematic review on DNA damage.

The evaluation of genotoxicity in workers exposed to different toxic agents is very important, especially considering the association between these exposures in a chronic context and DNA damage. Assessing biomarkers of exposure and, when possible, early biomarkers of effect, contributes to elucidating the potential toxic mechanisms involved in genotoxicity and its contribution to chronic non-communicable diseases. In Brazil, the biggest country in South America, workers are exposed to hazardous physical and chemical agents. Considering that these exposures occur, in most cases, throughout the worker's whole life, this is an important public health concern in Brazil. Therefore, this systematic review aims to analyze occupational exposure to chemical and physical agents and the association with DNA damage in studies carried out in Brazil from 1980 to 2021. A systematic and comprehensive literature search was performed in different databases based on occupational exposure to chemical and physical agents and DNA damage. Only full articles on studies that investigated experimental evidence on occupational exposure in Brazil and assessed DNA damage were included, amounting to 89 articles. Five main occupational exposure groups were identified: pesticides (36%), organic solvents (20%), dust and particles (16%), metals (11%), and ionizing radiation (6%). Another group called "others" included studies (11%) that did not fall into these main groups. It was found that comet assay and micronucleus tests are the most adopted methods to detect DNA damage. Occupational exposures were most associated with DNA damage. However, further improvements in study design would be needed to better characterize the association between biomonitoring and DNA damage, particularly to account for confounding factors.

Meta-analysis on the contents of trace elements in workers with occupational exposure to lead

Objective: To quantitatively evaluate the content differences of trace elements in workers with occupational exposure to lead. Methods: In January 2021, relevant literatures on the contents of trace elements in workers with occupational exposure to lead published from 1990 to 2020 were searched through CNKI, Wanfang, VIP, PubMed, web of science and Embase. Screened and extracted the literatures, and evaluated the quality of the included literatures with Newcastle Ottawa Scale. Meta analysis was performed with Review Manager 5.3 software, and standardized mean difference (SMD) and its 95% confidence interval were used as effect indicators. Results: A total of 20 literatures were included, and the quality scores were 5-7. The results of Meta-analysis showed that compared with the control group, the contents of blood zinc (SMD=-1.01, 95%CI: -1.53, -0.49) , hair zinc (SMD=-0.17, 95%CI: -0.33, -0.01) , hair copper (SMD=-0.50, 95%CI: -1.01, 0) , hair iron (SMD=-3.91, 95%CI: -5.80, -2.03) and hair manganese (SMD=-1.09, 95%CI: -2.02, -0.15) in occupational lead exposure group were significantly lower (P<0.05) . Compared with the control group, the content of cobalt in hair of occupational lead exposure group (SMD=1.41, 95%CI: 0.72, 2.10) was higher, and the difference was statistically significant (P<0.05) . There was no significant difference in the contents of blood chromium, blood copper, blood iron, blood manganese, blood selenium and hair nickel between the two groups (P>0.05) . Conclusion: Workers with occupational exposure to lead have abnormal trace elements.

Human Exposure Assessment of Mixed Metal/Loids at and Near Mega-Scale Open Beaching Shipwrecking Activities in Bangladesh

Pollution from shipwrecking is growing into a major occupational and environmental health concern worldwide, especially in the lower-middle-income countries where workers and residents may be exposed to potentially high levels of dispersed metal/loids due to decades of improper waste disposal. This study is the first to report the urinary biomarkers estimating the exposure of metal/loids and associated significant determinants in residents working and/or living at and near a major open beaching shipwrecking yard in Bangladesh. The concentrations of 17 elements were measured in urine and drinking water samples (125 each) using a validated ICP-MS method. Hydration variations of urine were best adjusted by specific gravity. Significantly higher (p < 0.001) urinary metal/loids load including cadmium and molybdenum in the occupational (70–80% of shipwrecking workers) and environmental exposure groups (72–75% of the local population) compared to the control site and international reference values suggest a significant health threat. Gender and age effects on the variation of urinary metal/loid concentrations were insignificant. However, fertilizer/pesticide users had higher nickel concentrations. Quantile regression analyses suggested the impacted locations with shipwrecking activities are significant predictors of exposure. The participants from the shipwrecking yards and the adjoining east, north, and south sites experienced significant exposure to metal/loids, which may be largely governed by wind-associated dispersion of contaminants. Water metal/loid concentrations were lower than the guideline values set by WHO and Bangladesh except for manganese in 63% of water samples. However, the elevated urinary concentrations of cadmium and thallium were significantly correlated to their concentration in water. This biomonitoring approach could be used as a background study to facilitate a more detailed exposure and health risk assessment to inform a management strategy for residents exposed to contaminated environmental matrices and dietary sources.

Meta-analysis of the effect of low-level occupational benzene exposure on human peripheral blood leukocyte counts in China

To investigate the effect of low-level occupational benzene exposure on human peripheral blood leukocyte counts of the workers, domestic and foreign published research data on the change of human peripheral blood leukocyte counts under low-level occupational benzene exposure from January 1990 to December 2020 were collected and analyzed. According to the literature inclusion and exclusion criteria, 18 independent studies from 12 publications were selected for meta-analysis to explore the effect of low-level occupational benzene exposure on human peripheral blood leukocyte counts. The results showed that the peripheral blood leukocyte counts abnormal rates of low-level occupational benzene exposure group were higher than those of the control group, and the difference was statistically significant. Low-level occupational benzene exposure could result in a relatively higher abnormal rate of peripheral blood leukocyte counts in the exposed population, indicating that low-level occupational benzene exposure at workplaces specified by the current benzene occupational exposure limit in China would affect the peripheral blood leukocyte counts of the workers, thus benzene with concentrations under the limit in the ambient air of workplace could be still harmful to the health of the exposed workers. The results of this study could provide a scientific basis for future revision of the benzene occupational exposure limit in China, and could also be a reference for the formulation of environmental standard concerning benzene in China in the future.

Induction of genotoxicity and mutagenic potential of heavy metals in Thai occupational workers

Heavy metals are widely used in many industries in Thailand and found in the environment. Occupational exposure to heavy metals is often chronic and caused by environmental contaminations, potentially leading to mutations and cancer. Although the genotoxic effects of occupational exposure to multiple heavy metals have been extensively studied, the findings regarding their genotoxicity are conflicting. In this study, we focused on investigating the genotoxic effects of certain heavy metals mixtures, including lead (Pb), copper (Cu), zinc (Zn), and tin (Sn), to which workers are exposed in the manufacturing industry. The cytokinesis-blocked micronucleus (CBMN) assay in peripheral blood lymphocytes was performed, and DNA damage was assessed by measuring tumour-associated protein levels and 8-hydroxy-2′-deoxyguanosine (8-OHdG) generated by oxidative stress that causes cytotoxicity. The occupational exposure group included 110 workers exposed to heavy metal mixtures and 105 matched control subjects. We found statistically significant differences in the blood Pb, Sn, and Cu levels between the exposed workers and the control subjects (p < 0.001). Analysis of micronuclei (MN) in peripheral blood lymphocytes revealed a significantly increased frequency of MN in exposed workers compared with that in control subjects (p<0.05). Non-smoking exposed workers were selected for 8-OHdG formation and mutant p53 tests, and significant differences in the mean plasma 8-OHdG concentration (p < 0.001) were found between the occupational exposure and the control group, but no differences were found in the levels of mutant p53. Thus, chronic exposure to different heavy metals causes genotoxic effects in humans. Furthermore, the CBMN assay and 8-OHdG formation can be used as surrogate biomarkers to identify and monitor groups with higher carcinogenic risk in the early stages of toxicity. In summary, our results indicate that mixtures of heavy metals (Pb, Sn, and Cu) in manufacturing industries pose an elevated health risk due to DNA damage.

Follow-Up of the Libby, Montana Screening Cohort: A 17-Year Mortality Study.

To evaluate mortality patterns among participants in a community-based screening program for asbestos-related disease. We calculated standardized mortality ratios (SMRs) and stratified results by exposure group (three occupational exposure groups, household contacts and residents without occupational asbestos exposure) and by radiographic abnormality presence. All-cause mortality (15.8%; 1,429/8,043) was statistically lower than expected. Asbestosis was statistically elevated in all exposure groups. Lung cancer was moderately associated with vermiculite miner/miller employment. Mesothelioma was elevated in that same exposure group and among residents. Systemic autoimmune disease mortality was also elevated. Radiographic parenchymal abnormalities were associated with lung cancer mortality. In addition to asbestos-related mortality in occupational exposure groups, this initial follow-up of this cohort also shows elevated mortality for some asbestos-related causes in non-occupational exposure groups.

Visualized Networking of Co-Regulated Lipids in Human Blood Based on High-Throughput Screening Data: Implications for Exposure Assessment

Exposure to environmental chemicals could disturb lipidome homeostasis in biotas. Comprehensive identification and interpretation of lipid molecules in biological samples are of great importance to elucidate the potential changes in lipid homeostasis upon exposure to various environmental stimuli. In this study, a total of 156 human blood samples were collected including 108 general citizens (control group) and 48 employees in a municipal solid waste incineration (MSWI) plant (occupational exposure group). More than 1500 lipid molecules, belonging to five lipid classes, were screened in the blood samples by UPLC-QTOF-MS in the MSE acquisition mode. All of the coupled compounds with correlation coefficients ( R) of 0.7 or higher were selected for automated network correlation analysis. A global visual network was automatically produced from thousands of coregulated lipid species in the blood samples. In the automatically produced molecular network, the distributions of the major correlated lipids were in accordance with their metabolic pathways in the KEGG map. Different lipidomic profiles in the blood samples from the two groups of people were easily observed by this visualization technique. Among the intrinsic lipid classes, glycererides and sterol lipids might represent the most sensitively affected lipids upon exposure to various pollutants emitted from the MSWI plant. The visualized network of coregulated lipids identified in human blood presents a new approach for interpreting the metabolic relationships among the thousands of metabolites identified in toxicological and epidemiological studies.

Increased time-to-pregnancy is associated with domestic work in South Africa.

BackgroundThe effects of female occupational exposures on fecundity have not been evaluated in South Africa. The aim of this study was to assess the effects of three specific occupational groups on time-to-pregnancy (TTP).MethodsThis cross-sectional study collected data, by means of a questionnaire, on 1210 women representative of a South African population, and sought information on: TTP for the most recent pregnancy, time-specific information on maternal factors and occupational exposures, as well as some paternal factors. Occupational exposure groups were determined using employment profile prior to the pregnancy. In the risk analysis, domestic workers and teachers were compared to administrative staff. Accidental and unplanned pregnancies were excluded from the analysis and participants who were never pregnant were censored. Discrete-time Cox regression models were built to estimate fecundability ratios (FR).ResultsThe median TTP in administrative workers, domestic workers and teachers was 4, 12 and 3 months respectively. After adjusting for a number of potential confounders, TTP was significantly related to occupation at the time of pregnancy attempt. Compared to administrative workers, domestic workers had a significantly lower per-cycle probability of conception (adjusted FR = 0.53; 95 CI 0.32–0.88). The per-cycle probability of conception in teachers compared to administrative workers was not significantly different (adjusted FR = 1.14; 95 CI: 0.75–1.72).ConclusionDomestic work was associated with prolonged TTP. Working as a domestic worker in South Africa may affect fecundity.

Effect of Occupational Exposure on A(H1N1)pdm09 Infection and Hospitalization.

To analyze relationships between occupational exposure and influenza infection and hospitalization during the 2009-2010 pandemic wave and the 2010-2011 influenza seasonal epidemic in Spain. Occupations were classified as high, medium, or low risk of influenza exposure. To assess the risk of infection, 588 outpatient cases of influenza confirmed by reverse-transcription polymerase-chain-reaction (RT-PCR) were compared with 588 outpatients without influenza symptoms. To assess the risk of hospitalization, 337 outpatient influenza cases were compared with 337 inpatient influenza cases. The high risk of occupational exposure group was composed only of health care workers. After adjustment for age, sex, vaccination status, and predictive variables of influenza infection, patients with a high risk of occupational exposure had an aOR of 2.14 (95%CI: 1.25-3.66) of being an outpatient influenza case and an aOR of 0.43 (95%CI: 0.20-0.95) of being an inpatient influenza case, compared with those with a low risk. A high risk of occupational exposure is a risk factor for influenza infection but not for hospitalization.

Missed Opportunities for HIV Prophylaxis Among Emergency Department Patients With Occupational and Nonoccupational Body Fluid Exposures

Exposures to HIV are frequently managed in the emergency department (ED) for assessment and potential initiation of HIV postexposure prophylaxis. Despite established guidelines, it is unclear whether patients with a nonoccupational exposure are managed similarly to patients with an occupational exposure. This retrospective study used an administrative database to identify consecutive patients at a single ED with a discharge diagnosis of "blood or body fluid exposure" without sexual assault from April 1, 2007 to June 30, 2013. Patient exposure details and physician management were ascertained according to predefined guidelines. The primary outcome was the proportion of patients with high-risk exposures who were correctly given HIV prophylaxis; the secondary outcome was the proportion of patients with low-risk exposures who were correctly not given HIV prophylaxis. Other outcomes included the proportion of patients who had a baseline HIV test in the ED, the proportion who followed up with an HIV test within 6 months, and the number of seroconversions in this group. All outcomes were compared between nonoccupational and occupational exposure. Of 1,972 encounters, 1,358 patients (68.9%) had an occupational exposure and 614 (31.1%) had a nonoccupational exposure. In the occupational exposure group, 190 patients (14.0%) were deemed high risk, with 160 (84.2%; 95% confidence interval [CI] 78.1% to 88.9%) appropriately given prophylaxis. In the nonoccupational exposure group, 287 patients (46.7%) had a high-risk exposure, with 208 (72.5%; 95% CI 66.8% to 77.5%) given prophylaxis, for a difference of 11.7% (95% CI 3.8% to 19.1%). For low-risk exposures, appropriate management of both occupational and nonoccupational exposure was similar (92.4% versus 93.0%). At the index ED visit, 90.5% of occupational exposure patients and 76.7% of nonoccupational exposure patients received HIV testing, for a difference of 13.8% (95% CI 10.1% to 17.7%). At 6 months, 25.4% of patients with an occupational exposure and 35.0% of patients with a nonoccupational exposure had a follow-up test, for a difference of -9.6% (95% CI -14.2% to -5.1%). Of patients who had follow-up testing within 6 months, 4 of 215 (1.9%) in the nonoccupational exposure group tested newly positive for HIV, whereas 0 of 345 (0%) in the occupational exposure group tested positive. For ED patients with blood or body fluid exposures, those with high-risk nonoccupational exposures were not given HIV prophylaxis nearly twice as often as those with high-risk occupational exposure. Although 6-month follow-up testing rates were low, 1.9% of high-risk nonoccupational exposure patients seroconverted.

CT Characteristics of Pleural Plaques Related to Occupational or Environmental Asbestos Exposure from South Korean Asbestos Mines

ObjectiveThis study evaluated the CT characteristics of pleural plaques in asbestos-exposed individuals and compared occupational versus environmental exposure groups.Materials and MethodsThis study enrolled 181 subjects with occupational exposure and 98 with environmental exposure from chrysotile asbestos mines, who had pleural plaques confirmed by a chest CT. The CT scans were analyzed for morphological characteristics, the number and distribution of pleural plaques and combined pulmonary fibrosis. Furthermore, the CT findings were compared between the occupational and environmental exposure groups.ResultsConcerning the 279 subjects, the pleural plaques were single in 2.2% and unilateral in 3.6%, and showed variable widths (range, 1-20 mm; mean, 5.4 ± 2.7 mm) and lengths (5-310 mm; 72.6 ± 54.8 mm). The chest wall was the most commonly involved (98.6%), with an upper predominance on the ventral side (upper, 77.8% vs. lower, 55.9%, p < 0.001) and a lower predominance on the dorsal side (upper, 74.9% vs. lower, 91.8%, p = 0.02). Diaphragmatic involvement (78.1%) showed a right-side predominance (right, 73.8% vs. left, 55.6%, p < 0.001), whereas mediastinal plaques (42.7%) were more frequent on the left (right, 17.6% vs. left, 39.4%, p < 0.001). The extent and maximum length of plaques, and presence and severity of combined asbestosis, were significantly higher in the occupational exposure group (p < 0.05).ConclusionPleural plaques in asbestos-exposed individuals are variable in number and size; and show a predominant distribution in the upper ventral and lower dorsal chest walls, right diaphragm, and left mediastinum. Asbestos mine workers have a higher extent of plaques and pulmonary fibrosis versus environmentally exposed individuals.

Risk related to the transmission of H5N1 subtype avian influenza virus in the environment of poultry markets in Changsha, China

To investigate the risk of H5N1 subtype avian influenza virus (AIV) transmission in the poultry market environment in Changsha city. H5N1 antibody levels among the groups related occupational exposure and AIV nucleic acid in the environment of poultry markets were detected. The characteristics of haemagglutinin (HA) genes of H5N1 AIV in the environment were analyzed. One district and one county from Changsha city were selected randomly and two poultry markets at inner city or township levels were selected in the same district or county respectively. H5N1 antibody of the occupational exposure groups in the poultry market was tested and AIV nucleic acid in the poultry market environment monitored. One hundred and two blood samples of the occupational exposure groups were tested for H5N1 antibody with single radioimmunoassay diffusion hemolysis (SRH) while 160 environment samples (from sewage, birds stools, feathers and smearing samples of poultry cages) in the poultry market were also detected for AIV nucleic acid with real-time PCR method. Four sewage samples of H5N1 subtype AIV were collected from poultry markets in Changsha, and the HA genes of H5N1 subtype AIV amplified by RT-PCR and then sequenced with TA cloning. Amino acid sequence alignment and phylogenetic tree analysis were conducted by Lasergene and Mega 5.0 software. The results through H5N1 antibody monitoring program showed that H5N1 antibody positive rates from workers were 25.5% (26/102), 50.0% (9/18) and 25.4% (17/67) respectively in the poultry markets of township and inner cities. H5N1 antibody positive rate in the township poultry markets was higher than in the inner cities poultry markets. from the surveillance on AIV nucleic acid showed that the overall H5 subtype positive rate in Changsha poultry markets was 31.3% (50/160), and the positive rate of townships poultry markets was 37.3% (31/83), which were both higher than those from the inner cities poultry markets (24.7%, 19/77). H5 subtype AIV positive rate was different in the tested specimens, with ranking of positive rates were sewage (50.0%, 24/48), feathers (44.5%, 4/9), birds stools (29.8%, 14/47) and smearing samples of poultry cages (14.3%, 8/56), with statistically significant differences (P < 0.01). Four H5N1 HA genes TA cloning were successfully constructed and identified as Eurasian branch, similar to viruses isolated in mainland China and Hong Kong in the same group, according to genetic analysis. Sequence data of the four HA genes showed the same feature of high pathogenicity, compared to the H5N1 AIV from mainland China of human origin. The receptor specificities were still with avian influenza origin (QSG) and the connecting peptide between HA1 and HA2 possessing the polybasic motif (RERRRKK or RERRGKK). One of the reasons for H5N1 antibody positive rate of 25.5% among poultry markets workers was that there were large numbers of H5N1 subtype AIV detected in the environment of poultry markets and HA genes of H5N1 subtype AIV in the poultry markets environment carried molecular characteristics of highly pathogenic which could increase the risk for H5N1 subtype AIV transmission in the environment of poultry markets.

Case-control study of paternal occupation and risk of childhood cancer in Great Britain, 1962–2006

ObjectivesPaternal exposure to carcinogens has been proposed as a risk factor for childhood cancer. Previous epidemiological studies, complicated by weak exposure assessments and limited case numbers, have reported mixed results,...