Occupational Benzene Exposure and Lung Cancer Risk: A Pooled Analysis of 14 Case-Control Studies.

Rationale: Benzene has been classified as carcinogenic to humans, but there is limited evidence linking benzene exposure to lung cancer. Objectives: We aimed to examine the relationship between occupational benzene exposure and lung cancer. Methods: Subjects from 14 case-control studies across Europe and Canada were pooled. We used a quantitative job-exposure matrix to estimate benzene exposure. Logistic regression models assessed lung cancer risk across different exposure indices. We adjusted for smoking and five main occupational lung carcinogens and stratified analyses by smoking status and lung cancer subtypes. Measurements and Main Results: Analyses included 28,048 subjects (12,329 cases, 15,719 control subjects). Lung cancer odds ratios ranged from 1.12 (95% confidence interval, 1.03-1.22) to 1.32 (95% confidence interval, 1.18-1.48) (Ptrend = 0.002) for groups with the lowest and highest cumulative occupational exposures, respectively, compared with unexposed subjects. We observed an increasing trend of lung cancer with longer duration of exposure (Ptrend < 0.001) and a decreasing trend with longer time since last exposure (Ptrend = 0.02). These effects were seen for all lung cancer subtypes, regardless of smoking status, and were not influenced by specific occupational groups, exposures, or studies. Conclusions: We found consistent and robust associations between different dimensions of occupational benzene exposure and lung cancer after adjusting for smoking and main occupational lung carcinogens. These associations were observed across different subgroups, including nonsmokers. Our findings support the hypothesis that occupational benzene exposure increases the risk of developing lung cancer. Consequently, there is a need to revisit published epidemiological and molecular data on the pulmonary carcinogenicity of benzene.

Occupational exposure to benzene and risk of non-Hodgkin lymphoma in an extended follow-up of two population-based prospective cohorts of Chinese men and women.

The carcinogenicity of benzene was reevaluated by the International Agency for Research on Cancer in 2017, with the Working Group reaffirming positive yet inconclusive associations with non-Hodgkin lymphoma (NHL). To extend our previous observation of a significant exposure-response for cumulative occupational benzene exposure and NHL risk among Chinese women in a population-based cohort in Shanghai, we extended follow-up of this cohort and pooled the data with a similarly designed population-based cohort of men in Shanghai. Cumulative exposure estimates were derived for 134,449 participants in the pooled analysis by combining ordinal job-exposure matrix intensity ratings with quantitative benzene measurements from an inspection database of Shanghai factories. Associations between benzene exposure metrics and NHL (n = 363 cases including multiple myeloma [MM]) were assessed using Cox proportional hazard models. Ever occupational exposure to benzene in the pooled population was associated with NHL risk (HR = 1.5, 95% CI = 1.2-2.0), and exposure-response relationships were observed for increasing duration (ptrend = .003) and cumulative exposure (ptrend = .003). Associations with ever exposure, duration, and cumulative exposure were similar for NHL with and without MM in the case definition, including lifetime cumulative exposures in the highest quartile (HR = 1.6, 95% CI = 1.1-2.4 with MM included; HR = 1.7, 95% CI = 1.1-2.7 with MM excluded). An elevated risk of the chronic lymphocytic leukemia subtype was suggested in the pooled analyses (HR for ever vs. never exposure = 2.3, 95% CI = 0.9-5.6). These observations provide additional support for a plausible association between occupational benzene exposure and risk of NHL.

Occupational exposure to endotoxins and small cell lung cancer: a systematic review with meta-analysis.

The relationship of occupational exposure to endotoxins with different histologic subtypes of lung cancer has not been established. Our objective was to conduct a systematic review with meta-analysis to assess the effect of exposure to endotoxins on the development of small cell lung cancer (SCLC). A bibliographic search was conducted using MEDLINE, Embase, CENTRAL, and Web of Science databases until December 2022, including all cohort and/or case-control studies that examined occupational exposure to endotoxins and SCLC. Risk of bias was assessed using the U.S. Office of Health Assessment and Translation tool. A random effects model was applied, publication bias were assessed, and a sensitivity analysis was conducted. Four papers were selected for meta-analysis purposes. A total of 144 incident cases of SCLC and 897 population or hospital controls were included. Occupational exposure to endotoxins was considered for textile/leather industry and agricultural sector workers exposed to endotoxins originating from wool, cotton, or leather dust. Except for one study, all investigations were classified as having a low probability of risk of biases. The results of the meta-analysis were not statistically significant (pooled OR: 0.86; 95% CI:0.69-1.08). In addition, neither between-study heterogeneity (I2=0%;p=0.92) nor publication bias was observed (p=0.49). The results of the sensitivity analysis, after including five studies that assessed the risk of SCLC among textile industry and crop/livestock farm workers (not specifically exposed to endotoxins), showed a negative statistically non-significant association and low between-study heterogeneity (pooled OR: 0.90; 95% CI:0.79-1.02; I2=22%;p=0.23). Subjects exposed to occupational exposure to endotoxins seem to exhibit a negative association with the development of SCLC, although the results are not conclusive.

Chronic occupational exposures to irritants and asthma in the CONSTANCES cohort.

OBJECTIVES: The impact of chronic occupational exposures to irritants on asthma remains discussed. We studied the associations between occupational exposures and asthma, with specific interest for chronic exposure to irritants, including disinfectants and cleaning products (DCPs) and solvents. METHODS: Cross-sectional analyses included 115 540 adults (55% women, mean age 43 years, 10% current asthma) working at inclusion in the French population-based CONSTANCES cohort (2012-2020). Current asthma was defined by ever asthma with symptoms, medication or asthma attacks (past 12 months), and the asthma symptom score by the sum of 5 respiratory symptoms (past 12 months). Both lifetime and current occupational exposures were assessed by the Occupational Asthma-specific Job-Exposure Matrix. Associations were evaluated by gender using logistic and binomial negative regressions adjusted for age, smoking status and body mass index. RESULTS: In women, associations were observed between current asthma and lifetime exposure to irritants (OR 1.05, 95% CI 1.00 to 1.11), DCPs (1.06, 95% CI 1.00 to 1.12) and solvents (1.06, 95% CI 0.98 to 1.14). In men, only lifetime exposure to DCPs (1.10, 95% CI 1.01 to 1.20) was associated with current asthma. Lifetime exposure to irritants was associated with higher asthma symptom score both in women (mean score ratio: 1.08, 95% CI 1.05 to 1.11) and men (1.11, 95% CI 1.07 to 1.15), especially for DCPs (women: 1.09, 95% CI 1.06 to 1.13, men: 1.21, 95% CI 1.15 to 1.27) and solvents (women 1.14, 95% CI 1.10 to 1.19, men: 1.10, 95% CI 1.05 to 1.15). For current exposures, no consistent associations were observed with current asthma and asthma symptom score. CONCLUSIONS: Lifetime occupational exposures to irritants were associated with current asthma and higher asthma symptom score. These exposures should be carefully considered in asthma management.

Trends in work-related respiratory diseases attributed to nickel, chromium and cobalt in the UK: descriptive findings from The Health and Occupation Research (THOR) network 1996-2019.

BACKGROUND: Occupational exposure to metals can be associated with respiratory diseases which can adversely affect the individual's health, finances and employment. Despite this, little is known about the incidence of these respiratory conditions over prolonged periods of time. AIMS: This study aimed to investigate the trends in the incidence of work-related respiratory diseases attributed to nickel, chromium and cobalt in the UK. METHODS: Cases of occupational respiratory diseases caused by nickel, chromium or cobalt reported to Surveillance of Work-related and Occupational Respiratory Disease (SWORD), the UK-based surveillance scheme between 1996 and 2019 (inclusive), were extracted and grouped into six 4-year time periods. Cases were characterised by causative metal exposure, occupational and industrial sector. Incidence rates diseases (adjusted for physician participation and response rate) were calculated using ONS employment data. RESULTS: Of cases reported to SWORD during the study period, 1% (173 actual cases) of respiratory problems were attributed to nickel, chromium or cobalt. Diagnoses of asthma compromised the largest proportion of diagnoses (74.4%), followed by lung cancer (8.9%) and pneumoconiosis (6.7%). Cases had a mean age of 47 years (SD 13); 93% were men. The annual incidence fell from 1.6 per million employed in the first 4-year period, to 0.2 in the most recent period. CONCLUSIONS: Over 24 years, a decline in the incidence of metal-related occupational respiratory diseases was observed in the UK. This could be attributed to improvements in working conditions which resulted in reduced metal exposure but could also be due to closure of industries that might have generated case returns.

Exposure to fibres and risk of pleural mesothelioma in the Norwegian Offshore Petroleum Workers cohort.

OBJECTIVES: Pleural mesothelioma is a rare respiratory cancer, mainly caused by inhalation of asbestos fibres. Other inorganic fibres are also suggested risk factors. We aimed to investigate the association between exposure to asbestos or refractory ceramic fibres (RCFs) and pleural mesothelioma among male Norwegian offshore petroleum workers. METHODS: Among 25 347 men in the Norwegian Offshore Petroleum Workers (NOPW) cohort (1965-1998), 43 pleural mesothelioma cases were identified through the Cancer Registry of Norway (1999-2022). A case-cohort study was conducted with 2095 randomly drawn non-cases from the cohort. Asbestos and RCF exposures were assessed with expert-made job-exposure matrices (JEMs). Weighted Cox regression was used to estimate HRs and 95% CIs, adjusted for age at baseline and pre-offshore employment with likely asbestos exposure. RESULTS: An increased risk of pleural mesothelioma was indicated for the highest versus lowest tertile of average intensity of asbestos (HR=1.21, 95% CI: 0.57 to 2.54). Pre-offshore asbestos exposure (vs no such exposure) was associated with increased risk of pleural mesothelioma (HR=2.06, 95% CI: 1.11 to 3.81). For offshore workers with no pre-offshore asbestos exposure, an increased risk of pleural mesothelioma was found for the highest tertile of average intensity of asbestos (HR=4.13, 95% CI: 0.93 to 18), versus the lowest tertile. No associations were found between RCF and pleural mesothelioma. CONCLUSIONS: Associations between JEM-based offshore asbestos exposure and pleural mesothelioma were confirmed in the NOPW cohort. Pleural mesothelioma risk was also associated with asbestos exposure before work in the offshore petroleum industry.

Occupational benzene exposure and colorectal cancer: A systematic review and meta-analysis.

Recent reports suggest that benzene exposure may be associated with solid cancers, such as lung and bladder cancers. Instead, evidence on the association between benzene and colorectal cancer (CRC) is sparse. Thus, we aimed to summarize current literature on the association between occupational benzene exposure and CRC. We searched Pubmed, Embase (through Ovid), and Scopus to retrieve cohort and nested case-control studies on the association between occupational benzene exposure and solid cancers. The search was initially completed in December 2022 and later updated in April 2024. We assessed quality of included studies using a modified version of Newcastle-Ottawa Scale. We computed pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) of CRC according to occupational benzene exposure, using the Paule-Mandel method. Twenty-eight studies were included in the meta-analysis. Most of them were conducted in Europe or North America (82.1%) and were industry-based (89.3%). Pooled RRs comparing workers exposed to benzene with those who were unexposed for incidence and mortality were 1.10 (95% CI: 1.06, 1.15) and 1.04 (95% CI: 0.97, 1.11) for CRC, 1.12 (95% CI: 1.01, 1.24) and 1.08 (95% CI: 0.99, 1.19) for colon cancer, and 1.04 (95% CI: 0.94, 1.14) and 1.05 (95% CI: 0.92, 1.19) for rectal cancer, respectively. Only one study supported the occurrence of a dose-response relationship between occupational benzene exposure and CRC, while others found no increase in risk according to dose of exposure or duration of employment. Our findings suggest that occupational benzene exposure may be associated with CRC. Further research with detailed assessment of individual-level exposure is warranted to confirm our results.

Occupational arsenic exposure and digestive and head and neck cancers: A systematic review and meta-analysis.

Arsenic is a known carcinogen for the lungs, the bladder, and the skin, while systematic evidence on other cancer types is lacking, especially for occupational exposure. Thus, we aimed to systematically summarize current evidence on the association between occupational arsenic exposure and digestive cancers, including head and neck cancer (HNC). We conducted a systematic review on Pubmed, Web of Science, and Embase search engines. We computed pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs) using DerSimonian and Laird random-effects model. Occurrence of publication bias was assessed using contour-enhanced funnel plots and Egger's test. Twenty-two studies on digestive cancers and 11 on HNC were included in the meta-analysis. RRs for the association with occupational exposure to arsenic of 1.23 (95% CI: 1.07-1.40; I2 = 72.3%, p < 0.001) and 1.08 (95% CI: 0.76-1.53; I2 = 76.6%, p < 0.001) for digestive cancer and HNC, respectively, were observed. As for specific cancer types, arsenic was associated with rectal cancer (RR: 1.51; 95% CI: 1.003-2.28; I2 = 37.0%, p = 0.174), but not with other investigated cancer types. No clear evidence of publication bias was found. The results of our study suggest that the observed association between occupational arsenic exposure and digestive cancer might be mainly driven by a positive association for rectal cancer, while arsenic exposure did not appear to be associated with HNC. However, further high-quality studies with detailed assessment of arsenic exposure are warranted to clarify the potential association of arsenic with digestive cancers and HNC.

Neurological and neurobehavioral effects of welders in Egypt exposed to manganese containing welding fumes.

PURPOSE: Welders are more likely to develop neurobehavioral disorders because of their exposure to neurotoxic metals such as manganese. This study aimed to measure the neurobehavioral performance of welders occupationally exposed to manganese at welding enterprises and its relationship with the workplace environment. METHODS: It is a comparative cross-sectional study carried out on 130 welders working at 50 welding enterprises in Menoufia governorate, Egypt, compared to 130 non-occupationally exposed controls. RESULTS: It was found that the environments of the studied welding enterprises had levels of respirable dust, manganese, and total welding fumes that exceeded internationally permissible limits. In addition, the mean blood manganese levels were significantly higher among welders (4.16 ± 0.61) than the controls (1.72 ± 0.41). Welders had a significantly higher prevalence of neurological manifestations and lower performance of neurobehavioral tests. Lower neurobehavioral performance among welders was significantly correlated with increased work duration and blood levels in some tests. CONCLUSION: To lessen the fumes in the breathing zone of workers, it is therefore strongly recommended to regularly wear high-quality personal protective equipment, especially masks, and to ensure proper ventilation.

Prevalent occupational exposures and risk of lung cancer among women: Results from the application of the Canadian Job-Exposure Matrix (CANJEM) to a combined set of ten case-control studies.

BACKGROUND: Worldwide, lung cancer is the second leading cause of cancer death in women. The present study explored associations between occupational exposures that are prevalent among women, and lung cancer. METHODS: Data from 10 case-control studies of lung cancer from Europe, Canada, and New Zealand conducted between 1988 and 2008 were combined. Lifetime occupational history and information on nonoccupational factors including smoking were available for 3040 incident lung cancer cases and 4187 controls. We linked each reported job to the Canadian Job-Exposure Matrix (CANJEM), which provided estimates of probability, intensity, and frequency of exposure to each selected agent in each job. For this analysis, we selected 15 agents (cleaning agents, biocides, cotton dust, synthetic fibers, formaldehyde, cooking fumes, organic solvents, cellulose, polycyclic aromatic hydrocarbons from petroleum, ammonia, metallic dust, alkanes C18+, iron compounds, isopropanol, and calcium carbonate) that had lifetime exposure prevalence of at least 5% in the combined study population. For each agent, we estimated lung cancer risk in each study center for ever-exposure, by duration of exposure, and by cumulative exposure, using separate logistic regression models adjusted for smoking and other covariates. We then estimated the meta-odds ratios using random-effects meta-analysis. RESULTS AND CONCLUSIONS: None of the agents assessed showed consistent and compelling associations with lung cancer among women. The following agents showed elevated odds ratio in some analyses: metallic dust, iron compounds, isopropanol, and organic solvents. Future research into occupational lung cancer risk factors among women should prioritize these agents.

Incidence of cardiovascular disease in a cohort of mine workers exposed to ultrafine aluminum powder in Ontario, Canada.

BACKGROUND: A retrospective cohort study was conducted to estimate associations between an ultrafine aluminum powder, McIntyre Powder (MP), and cardiovascular disease incidence in a cohort of mine workers from Ontario, Canada. Disease outcomes included ischemic heart disease (IHD), acute myocardial infarction (AMI), congestive heart failure (CHF), and strokes and transient ischemic attacks (STIA). METHODS: Using work history records from the Ontario Mining Master File (MMF) mine workers were followed for disease incidence in administrative health records. The analysis included 25,813 mine workers who were exposed to MP between 1943 and 1979 and followed for cardiovascular disease (CVD) diagnoses between 2006 and 2018. Cardiovascular disease cases were ascertained using physician, hospital, and ambulatory care records. Poisson regression models were used to estimate age and birth-year adjusted incidence rate ratios (RR) and 95% confidence intervals (CI) for associations between MP exposure and CVD outcomes. RESULTS: Ever-exposure to MP was positively associated with modest increases in the incidence rate of IHD, AMI, and CHF, but not STIA, using both assessment approaches. Duration of self-reported MP exposure was positively associated with monotonically increasing rates of IHD and AMI compared to never-exposed miners, with the greatest association observed among miners with >20 years of exposure (for IHD: RR 1.24, 95% CI: 0.91-1.68; and for AMI: RR 1.52, 95% CI 1.01-2.28). CONCLUSION: Mine workers ever-exposed to MP had modestly elevated rates of CVD. The rate of CVD diagnoses appeared to increase with longer duration of exposure when assessed by both self-reported exposure and through historical records.

Mortality and cancer incidence in perfluorooctanesulfonyl fluoride production workers.

BACKGROUND: Exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with several health outcomes, though few occupationally-exposed populations have been studied. We evaluated mortality and cancer incidence in a cohort of perfluorooctanesulfonyl fluoride-based specialty chemical manufacturing workers. METHODS: The cohort included any employee who ever worked at the facility from 1961 to 2010 (N = 4045), with a primary interest in those who had 365 cumulative days of employment (N = 2659). Vital status and mortality records were obtained through 2014 and the cohort was linked to state cancer registries to obtain incident cancer cases from 1995 to 2014. Cumulative exposure was derived from a comprehensive exposure reconstruction that estimated job-specific perfluorooctanesulfonate (PFOS)-equivalents (mg/m3 ) exposure. Overall and exposure-specific standardized mortality ratios (SMR) were estimated in reference to the US population. Hazard ratios (HRs) and 95% confidence interval (CI) for cumulative PFOS-equivalent exposure (log2 transformed) were estimated within the cohort for specific causes of death and incident cancers using a time-dependent Cox model. RESULTS: Death rates were lower than expected except for cerebrovascular disease (SMR = 2.42, 95% CI = 1.25-4.22) and bladder cancer (SMR = 3.91, 95% CI = 1.07-10.02) in the highest exposure quartile. Within the cohort, the incidence of bladder, colorectal, and pancreatic cancer were positively associated with exposure, however except for lung cancer (HR = 1.05, 95% CI = 1.00-1.11) the CIs did not exclude an HR of 1. CONCLUSIONS: This study provides some evidence that occupational exposure to PFOS is associated with bladder and lung cancers and with cerebrovascular disease.

Gastrointestinal cancer and occupational diesel exhaust exposure: a meta-analysis of cohort studies.

BACKGROUND: Diesel exhaust exposure and cancer other than the lungs have been limitedly investigated. AIMS: To conduct a systematic review and meta-analysis on the association between occupational exposure to diesel exhaust and gastrointestinal cancers. METHODS: Two researchers performed a systematic literature review to identify all cohort studies on occupational exposure to diesel exhaust and risk of cancers other than lung. Of the 30 retained studies, 10 reported risk estimates for oesophageal, 18 on gastric, 15 on colon and 14 on rectal cancer. We performed random-effects meta-analyses to calculate summary relative risks (RRs) and 95% confidence intervals (CIs) for ever-exposure to diesel exhaust. RESULTS: We calculated summary RR = 1.08 (95% CI 0.97-1.21, P heterogeneity = 0.06) for oesophageal, 1.06 (95% CI 0.99-1.14, P < 0.001) for gastric, 0.98 (95% CI 0.96-1.00, P = 0.453) for colon, and RR = 1.04 (95% CI 0.97-1.11, P = 0.013) for rectal cancer. Drivers showed an association with oesophageal (RR = 1.26, 95% CI 0.99-1.62), gastric (RR = 1.20, 95% CI 0.91-1.59) and rectal cancer (RR = 1.41, 95% CI 1.13-1.75); machine operators with oesophageal (RR = 1.09, 95% CI 1.00-1.20) and gastric (RR = 1.15, 95% CI 1.10-1.20) and handlers with oesophageal cancer (RR = 1.95, 95% CI 1.23-3.09). Studies from Europe revealed an association with gastric cancer while those from North America did not (P < 0.05). No difference was found by quality score except for gastric cancer, where high-quality studies but not low-quality ones showed increased risk (P heterogeneity = 0.04). There was no evidence of publication bias. CONCLUSIONS: An increased but insignificant risk of oesophageal, gastric and rectal, but not colon cancer, was suggested in workers exposed to diesel exhaust. Residual confounding cannot be excluded.

Assessing lifetime occupational chrysotile inhalation exposure, respiratory symptoms, and lung cancer risk among brake maintenance workers in Malaysia.

This study aimed to estimate workers' occupational lifetime exposure to chrysotile and examine the respiratory symptoms and lung cancer risk. A total of 112 workers were interviewed about their occupational histories. Exposure modeling using information on the determinants of exposure was used to estimate chrysotile emissions. The cumulative lifetime exposure was then assessed for each worker. Respiratory symptoms were obtained using a validated questionnaire. Lung cancer mortality rate was also predicted using a model. Almost all the workers were male and young (mean age = 30 years, SD = 7). The estimated lifetime occupational chrysotile inhalation exposure ranged from 0.0001 to 0.0486 f/mL.years (median = 0.0018 f/mL.years, IQR = 0.486). A high prevalence of cough symptom (11.7%), and low estimated cancer risk (<1%) were reported. In conclusion, the lung cancer risk among our cohort of workers was at a low level because of lower cumulative lifetime occupational chrysotile exposure.

Carcinogenicity of asbestos-free talc and talcum powder: A systematic review of the epidemiological evidence after the 2006 monograph of the International Agency for Research on Cancer.

BACKGROUND: in 2006, the International Agency for Research on Cancer (IARC) concluded that the evidence of carcinogenicity for asbestos-free talc was inadequate (group 3), whereas perineal use of talcum powder was classified as possibly carcinogenic (group 2B). OBJECTIVES: to assess whether later studies provide more solid information on the carcinogenic risk from asbestos-free talc and talcum powder and a better characterization of exposure. DESIGN: systematic review. METHODS: cohort studies of talc miners and millers exposed to asbestos-free talc, as well as cohort and case-control studies reporting cancer risk in talc powder consumers published from 2006 onwards were identified through PubMed and reference lists. Pooled analyses were included, but not reviews and meta-analyses. In the case of repeatedly reported studies, the article with the longest follow-up or the largest number of observed cases was selected for data abstraction. Notice was taken of studies which were both reported individually and included in pooled analyses. RESULTS: publications meeting inclusion criteria were: 2 cohort studies on talc miners and millers, 10 cohort studies on talcum powder users (4 of which estimated ovarian cancer risk), and 14 case-control studies (13 on ovarian and 1 on endometrial cancer) on the risk from talcum powder use. No excess cancer mortality has been reported among asbestos-free talc miners and millers. Case-control studies consistently led to estimates of ovarian cancer excesses associated with the use of perineal talcum powder (odds ratios up to 1.5). Most studies quantifying exposure also provided evidence of a dose-response relationship. Individual cohort studies estimated hazard ratios (HR) just above 1. In an analysis of pooled cohorts for a total of 3,112 cases, the HR for women with patent reproductive tract was 1.13 (95%CI 1.01-1.26) with a correlation between HR and frequency of use (p for trend 0.03). In all cohort studies, the perineal use of talcum powder was measured only once in the early phases of follow-up, thus producing an inaccurate measure of cumulative exposure. Results of epidemiological studies regarding cancer risk in other organs are limited and inconsistent. CONCLUSIONS: epidemiological studies updated or published after IARC 2006 evaluation indicate that: no increase in cancer risk is apparent among miners and millers of asbestos-free talc; risk for ovarian cancer increases following the perineal use of commercial talcum powder. A correlation between indicators of quantity of use and cancer risk is suggested by a number of studies. The composition of talcum powders considered in such studies is not known.

Occupational Exposure to Benzene and Risk of Breast Cancer: Systematic Review and Meta-Analysis.

INTRODUCTION: Benzene is a recognized carcinogen; however, its association with breast cancer is not well established. Hence, a meta-analysis of cohort and case-control studies was performed to determine the association between occupational benzene exposure and the risk of breast cancer. METHODS: A systematic literature review identified 7573 publications from which 23 cohort and case-control studies were retained and evaluated using meta-analyses (fixed effects model). PRISMA guidelines were followed. Our protocol was registered in the PROSPERO database (Registration No. CRD42022379720). Study quality was assessed using a modified Newcastle-Ottawa scale (NOS). RESULTS: The summary relative risk (RR) for ever-benzene exposure was 1.08 (95% CI=1.03-1.14, I2=38.6%, n=23 risk estimates); corresponding RR for cancer incidence and mortality were 1.08 (95% CI=1.02-1.14, I2=56.1%, n=16) and 1.10 (95% CI=0.87-1.37, I2<0.001%, n=10). However, heterogeneity was detected for sex (p-het=0.002), publication year (p-het<0.001), study design (p-het<0.001), study quality (p-het<0.001), and industry of employment (p-het=0.03). The RR for high level of exposure showed positive association with breast cancer 1.35 (95% CI=1.06-1.72, I2 =<0.001%, n=3) and (P-het=0.64). Publication bias was detected (p=0.03). CONCLUSIONS: The results of our meta-analysis indicate a positive association between occupational benzene exposure and an increased risk of breast cancer, particularly when exposed to higher levels of benzene. However, bias and confounding could not be excluded.

Risk of Skin Cancer in Workers Exposed to Diesel Exhaust: A Systematic Review and Meta-Analysis of Cohort Studies.

BACKGROUND: Our objective was to study the association between occupational exposure to diesel exhaust (DE) and skin cancer. METHODS: A systematic review following STROBE guidelines and PECOS criteria was conducted to identify cohort studies describing the association between occupational DE exposure and the risk of skin cancer. We extracted 12 independent risk estimates for melanoma skin cancer (MSC), 8 for non-melanoma skin cancer (NMSC), and 3 for skin cancer not otherwise specified (SC-NOS). Random effects meta-analyses were performed, site-specific and stratified by geographic region and quality score. 95% confidence intervals (CI) were reported. Between-study heterogeneity and potential publication bias were investigated. RESULTS: There was no overall evidence of an increased risk of MSC [RR=0.90, 95% CI: 0.73-1.11; I2=92.86%, 95% CI: 82.83-97.03%], NMSC [RR=1.04, 95% CI: 0.88-1.23; I2=60.79%, 95% CI: 0-87.34%] or SC-NOS [RR=0.72, 95% CI: 0.54-0.97; I2=26.60%, 95% CI: 0-94.87%] in workers exposed to DE. No difference between low-quality and high-quality studies was found. A stratified analysis by geographical region did not reveal any significant differences. There was no evidence of publication bias. CONCLUSIONS: No evidence of an association between skin cancer and occupational DE exposure was found. Residual confounding and other sources of bias cannot be ruled out.

Risk of Gynecological and Breast Cancers in Workers Exposed to Diesel Exhaust: A Systematic Review and Meta-Analysis Of Cohort Studies.

BACKGROUND: This study aimed to explore the association between occupational exposure to diesel exhaust (DE) and gynaecological and breast cancers. METHODS: A systematic review was performed to identify cohort studies reporting results on the association between occupational exposure to DE and risk of gynaecological and breast cancers. STROBE guidelines and PECOS criteria were followed. We identified 6 studies for breast cancer (BC), 4 for cervical cancer (CC), 4 for endometrial cancer (EC) and 7 for ovarian cancer (OC). Random-effects meta-analyses were conducted on the relationship between DE exposure and BC, CC, EC, and OC risk; 95% confidence intervals (CI) and prediction intervals (PI) were reported. We investigated between-study heterogeneity and potential publication bias using Egger's test. RESULTS: No associations were observed between occupational DE exposure and risk of BC [RR=0.93; CI: 0.77-1.13; PI:0.50-1.73, I2=80.31%], EC [RR=0.89; CI: 0.75-1.05; PI:0.61-1.30, I2=0.78%], and OC [RR=1.08; CI: 0.89-1.32, PI: 0.76-1.56, I2=11.87%]. A weak association was observed for CC [RR=1.41; CI: 1.17-1.17; PI:0.85-2.30, I2=6.44%]. No between-study heterogeneity or publication bias was detected. CONCLUSIONS: This study identified an association between DE exposure and CC, which was not adjusted for potential confounders. No evidence of an association was found with BC, EC, and OC.

[Three cases of occupational chronic chloropropene poisoning].

Chronic chloropropene poisoning is a disease mainly caused by peripheral nerve damage due to close contact with chloropropene in industrial production, its clinical manifestations include varying degrees of sensory, motor, or tendon reflex disorders in the distal limbs, and neuromyography can show neurogenic damage. This article analyzed and summarized the clinical characteristics, diagnosis and treatment methods of three patients with occupational chronic chloropropene poisoning, in order to enhance the clinical understanding of occupational chronic chloropropene poisoning and provide reference for clinical diagnosis and treatment.

[Delphi method investigation and research on the revision of Diagnosis of Occupational Arsenic Poisoning (GBZ 83-2013)].

Objective: To explore the expert opinions on the revision of the Diagnosis of Occupational Arsenic Poisoning (GBZ 83-2013) . Methods: In March 2023, the improved Delphi expert consultation method was adopted, in the first round of consultation, a pre-survey was conducted on 20 experts, and the questionnaire was improved according to the experts' opinions. Then, a second round of expert consultation questionnaire was formed to conduct a questionnaire survey and consultation of 50 experts engaged in occupational disease diagnosis and related work. The feedback of experts was collected and analyzed. Results: The average score for the scientificity and progressiveness of the main technical content of the original standard was 3.33, and the average score for the rationality and operability of the main technical content of the original standard was 3.25. The importance of individual indicators with specific connotations were ranged from 4.20 to 4.45, with coefficients of variation <0.25, and the experts' opinions were relatively concentrated. The experts have provided feedback indicating that the original standard had issues such as lack of continuity in diagnostic gradation, the need to integrate biomarkers with urinary and hair arsenic levels, a scarcity of objective diagnostic indicators, the removal of exposure response from the main text, and a low level of consistency in standard usage. These issues need to be revised urgently. Conclusion: The Diagnosis of Occupational Arsenic Poisoning (GBZ 83-2013) should be revised based on experts' feedback and suggestions to meet the current real demand for occupational arsenic poisoning diagnosis.