Occupational Benzene Exposure Research Articles

Global, regional, and national burden of acute myeloid leukemia, 1990–2021: a systematic analysis for the global burden of disease study 2021

BackgroundAcute myeloid leukemia (AML), as the most common subtype of leukemia in adults, is characterised by rapid progression and poor prognosis. In the context of the rapid development of medical technology and the complexity of social factors, a detailed report describing the latest epidemiological patterns of AML is important for decision makers to allocate healthcare resources effectively.MethodsOur research utilized the latest data sourced from the Global Burden of Disease (GBD) 2021. To delineate the burden of AML, we comprehensively described the incidence, deaths, disability-adjusted life years (DALYs), and the associated age-standardized rates per 100,000 persons (ASR) spanning from 1990 to 2021 stratifies according to age, sex, socio-demographic index (SDI), and nationality. Additionally, we extracted and analyzed data about the risk factors that contribute to AML-related deaths and DALYs.ResultsAccording to our study, the incidence of AML has continued to rise globally from 79,372 in 1990 to 144,645 in 2021 and AML affected the male and the elderly populations disproportionately. Furthermore, there was a significant positive correlation between the burden of AML and the SDI value. Developed nations generally exhibited higher age-standardized incidence rate, age-standardized death rate, and age-standardized disability-adjusted life year rate than the developing nations. We also analyzed the prevalence of smoking, high body mass index, and occupational benzene and formaldehyde exposure in the AML population in different SDI regions. Moreover, smoking and high body mass index were more prevalent in developed countries, whereas occupational exposure to these chemicals was the predominant risk factor in developing countries.ConclusionThe global burden of AML has increased over the past 32 years, with rising morbidity and mortality. The incidence of AML is differentially distributed across different SDI countries or regions. AML incidence is higher in the elderly and in men. The proportions of smoking, high body mass index, and occupational exposure to benzene and formaldehyde varied by region. The findings highlight the need for region-specific prevention and call for future research on preventive strategies and new treatments to lower AML incidence and improve patient outcomes.

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 benzene exposure and risk of kidney and bladder cancers: a systematic review and meta-analysis.

Benzene is recognized as leukemogenic. However, the association between it and solid cancers has been the subject of less investigation. We aim to conduct a systematic review and meta-analysis to evaluate the association between occupational exposure to benzene and the risk of urinary tract cancer, including kidney and bladder. We included 41 cohort and case-control studies listed in the most recent International Agency for Research on Cancer (IARC) Monograph on benzene exposure and the result of a literature review to identify more recent studies. Forest plots of relative risk (RR) were constructed for kidney, bladder, and urinary tract cancer overall. A random-effects model was used to address heterogeneity between studies. Stratified analyses were conducted to explore effect modification. Our findings revealed an association between exposure to occupational benzene and kidney and unspecified urinary tract cancers (RR = 1.20, 95% confidence interval = 1.03-1.39), and an association of borderline statistical significance with bladder cancer (RR = 1.07, 95% confidence interval = 0.97-1.18). Publication bias was excluded for both kidney (P = 0.809) and bladder cancer (P = 0.748). Stratification analysis according to the selected study characteristics showed no difference except regarding the industry for kidney cancer (P < 0.000), with a stronger association in the chemical industry. An analysis by exposure level did not reveal any trend for kidney cancer, whereas there was a trend (P = 0.01) for bladder cancer. Our study found an association between occupational benzene exposure and kidney cancer and a dose-effect association between benzene exposure and bladder cancer.

Occupational benzene exposure and cancer risk among Chinese men: A report from the Shanghai Men's Health Study.

Benzene exposure has been associated with increased leukemia and other cancer risk; however, epidemiological evidence is inconsistent for the latter and confounding from smoking and alcohol was rarely adjusted. We investigated associations of occupational benzene exposure and risk of leukemia, lymphoma, myeloma, lung, stomach, liver, and kidney cancers in a population-based cohort of 61,377 men ages 40-74. A job-exposure matrix, constructed by industrial hygienists specifically for the study population, was used to derive cumulative benzene exposure from all jobs held. Cox regressions were performed to estimate adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for benzene-cancer risk associations with adjustment for potential confounders. Over 15-years of follow-up, 1,145 lung, 656 stomach, 445 liver, 243 kidney cancer cases, 100 leukemia, 124 lymphoma, and 46 myeloma cases were identified. Benzene exposure >550mg/m3 was associated with increased leukemia (aHR=2.3, 95%CI=1.1-4.5), lung (aHR=1.2, 95%CI=1.0-1.6), and stomach (aHR=1.4, 95%CI=1.0-1.9) cancer risk; benzene-exposure was associated with early cancer diagnosis age. The benzene-leukemia and -stomach cancer associations followed a linear dose-response pattern (Plinear=0.016 and 0.023), whereas benzene-lung cancer association was evident at higher exposure levels (Pnon-linear=0.027). Alcohol consumption modified the benzene-leukemia association (HR=3.0, 95%CI=1.1-8.3 for drinkers, aHR=0.9, 95%CI=0.4-2.0 for non-drinkers, Pinteraction=0.047). Benzene exposure was associated with increased leukemia, stomach, and lung cancer risk. Alcohol consumption may modify the benzene-leukemia association, although estimates are imprecise. Our study provides additional evidence that benzene exposure increases cancer risk beyond leukemia, information important for policymakers to develop programs to mitigate cancer risk among benzene-exposed workers.

Biomarkers of occupational benzene exposure: A Systematic Review to estimate the exposure levels and individual susceptibility at low doses.

Benzene is associated with diverse occupational and public health hazards. It exhibits an ability to rapidlypermeate the skin and contaminate water and food sources, leading to dermal and ingestion exposures. Despite numerous studies examining the associations between benzene and various indicators of harm, the findings have yielded inconsistent results. Furthermore, relying solely on air concentration as a measure of benzene exposure is limited, as it fails to account for internal exposure dose and individual susceptibility. This study aimed to conduct a comprehensive review in order to present current knowledge on benzene biomarkers and their significance in evaluating exposure levels and associated health hazards. The search methodology adhered to the PRISMA guidelines and involved the application of specific inclusion and exclusion criteria across multiple databases including PubMed, Embase, and Web of Science. Two researchers independently extracted and evaluated the relevant data based on predetermined criteria. Following the screening process, a total of 80 articles were considered eligible out of the initially retrieved 1053 articles after undergoing screening and assessment for inclusion. As the level of exposure decreased, specific biomarkers demonstrated a gradual increase in limitations, including heightened background concentrations and vulnerability to confounding factors. The advancement of sampling and analysis techniques will yield new biomarkers. Additionally, when conducting practical work, it is crucial to employ a comprehensive utilization of diverse biomarkers while excluding individual metabolic variations and combined exposure factors.

Occupational exposure to benzene and mortality risk of lymphohaematopoietic cancers in the Swiss National Cohort.

Previous studies established a causal relationship between occupational benzene exposure and acute myeloid leukemia (AML). However, mixed results have been reported for associations between benzene exposure and other myeloid and lymphoid malignancies. Our work examined whether occupational benzene exposure is associated with increased mortality from overall lymphohaematopoietic (LH) cancer and major subtypes. Mortality records were linked to a Swiss census-based cohort from two national censuses in 1990 and 2000. Cases were defined as having any LH cancers registered in death certificates. We assessed occupational exposure by applying a quantitative benzene job-exposure matrix (BEN-JEM) to census-reported occupations. Exposure was calculated as the products of exposure proportions and levels (P × L). Cox proportional hazards models were used to calculate LH cancer death hazard ratios (HR) and 95% confidence intervals (CI) associated with benzene exposure, continuously and in ordinal categories. Our study included approximately 2.97 million persons and 13 415 LH cancer cases, including 3055 cases with benzene exposure. We observed increased mortality risks per unit (P × L) increase in continuous benzene exposure for AML (HR 1.03, 95% CI 1.00-1.06) and diffuse large B-cell lymphoma (HR 1.09, 95% CI 1.04-1.14). When exposure was assessed categorically, increasing trends in risks were observed with increasing benzene exposure for AML (P=0.04), diffuse large B-cell lymphoma (P=0.02), and follicular lymphoma (P=0.05). In a national cohort from Switzerland, we found that occupational exposure to benzene is associated with elevated mortality risks for AML, diffuse large B-cell lymphoma, and possibly follicular lymphoma.

Abstract 835: Occupational-related exposure to benzene and risk of female genital cancers: Systematic review and meta-analysis

Abstract Purpose: The IARC monograph has classified benzene as a class I carcinogen, as evidenced by its association with hematological malignancies. However, its association with female genital cancers (ovarian, uterine, cervical) has not been characterized. Therefore, a meta-analysis of cohort studies was performed to determine the possible correlation between occupational benzene exposure and the risk of female genital cancers. Methods: A systematic literature review was conducted that identified 7221 relevant publications. A total of 9 cohort studies detailing occupational exposure to benzene and correlated risk of ovarian, uterine, and cervical cancers were retained, and a meta-analysis (using fixed effects model) was performed. PECOS criteria and STROBE guidelines were followed, and the study protocol was registered in the PROSPERO database (Reg. No. 379720). Study quality was assessed using a modified Newcastle-Ottawa scale (NOS). Results: The summary relative risk (RR) for ever-benzene exposure was 1.22 (95% CI=1.03-1.44, I2&amp;lt;0.001%, n=19); corresponding RR results for female genital cancers incidence and mortality were 1.09 (95% CI=0.92-1.29, I2=5.0%, n=17) and 1.69 (95% CI=1.18-2.4, I2&amp;lt;0.001%, n=9), respectively. These findings were confirmed in sub-analyses by geographical area, industry type, publication year, and levels of benzene exposure. Heterogeneity was detected amongst industries of employment (p-het=0.012) which included petroleum, chemical, printing, and mixed industries categories. Notably, the printing industry (compositors, press operators, and bookbinders) had a summary RR of 2.56 (95% CI=1.45-4.52, I2=35.0%, n=2). However, no heterogeneity was observed for geographical regions (p-het=0.77), duration of benzene exposure (p-het=0.73), publication year (p-het=0.89), or among varying study quality (&amp;lt; or ≥ median NOS score; p-het=0.14). No publication bias was detected (p=0.43). Conclusions: Our meta-analysis identified an association between occupational benzene exposure and the risk of female genital cancers. The association was restricted to the industry of employment. Effects of residual confounding variables cannot be excluded, however, given the present association, there is a potential for causality, especially in workers employed in the printing industry. Citation Format: Darshi Shah, Vincent DeStefano, Veer Shah, Monireh Sadat Seyyedsalehi, Mattia Bonetti, Paolo Boffetta. Occupational-related exposure to benzene and risk of female genital cancers: Systematic review and meta-analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 835.

Abstract 831: Occupational-related exposure to benzene and risk of breast cancer: Systematic review and meta-analysis

Abstract Purpose: Benzene is a recognized carcinogen as evidenced by its association with leukemia; 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 benzene exposure and the risk of breast cancer. Methods: A systematic literature review was conducted and 7221 publications were identified, from which 21 cohort and case-control studies were retained, and evaluated using meta-analyses (fixed effects model). PECOS criteria and STROBE guidelines were followed, and the study protocol was registered in the PROSPERO database (Registration No. 379720). 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=1.02-1.14, I2=43.6%, n=21); corresponding RR for cancer incidence and mortality were 1.08 (95% CI=1.02-1.14, I2=58.6%, n=15) and 1.09 (95% CI=0.87-1.38, I2&amp;lt;0.001%, n=9), respectively. These main results were confirmed in sub-analyses by geographical region, industry type, publication year, and levels of exposure. No heterogeneity was detected amongst geographical regions (p-het=0.19), industry of employment (p-het=0.05) or and duration of the dose (low, high; p-het=0.64). Studies published before 2003 reported a summary RR of 1.24 (95% CI=1.13-1.37), compared to a summary RR of 1.02 (95% CI=0.95-1.08) for studies published later (p-het=0.001). Heterogeneity was observed when evaluating studies at and above, or below the NOS mean (p-het=0.00), with a summary RR of 1.25 (95% CI=1.13-1.28, I2&amp;lt;0.001%, n=9) for studies below the median NOS score. Sub-group analysis of study design demonstrated heterogeneous results (p-het=0.001) with a summary RR of 1.19 (95% CI=1.10-1.29, I2&amp;lt;0.001%, n=16) for cohort studies while compared to the findings of case-control studies. Publication bias was detected (p=0.04). Conclusions: Our meta-analysis identified an association between occupational benzene exposure and risk of breast cancer. The association was restricted to studies published before 2003, below the median NOS score, and cohort studies. Residual confounding variables cannot be excluded, which, together with potential bias, prevents conclusions of causality. Citation Format: Vincent DeStefano, Darshi Shah, Veer Shah, Monireh Sadat Seyyedsalehi, Mattia Bonetti, Paolo Boffetta. Occupational-related exposure to benzene and risk of breast cancer: Systematic review and meta-analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 831.

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 Benzene Exposure in the Norwegian Offshore Petroleum Industry, 2002-2018.

PurposeWorkers on offshore petroleum installations are at risk of being exposed to benzene which is carcinogenic to humans. The present study aimed to assess the time trend of full-shift benzene exposure from 2002 to 2018 in order to characterize benzene exposure among laboratory technicians, mechanics, process operators, and industrial cleaners, and to examine the possible determinants of benzene exposure.MethodsA total of 924 measurements of benzene exposure from the Norwegian petroleum offshore industry were included. The median sampling duration was 680 min, ranging from 60 to 940 min. The overall geometric mean (GM) and 95% confidence interval, time trends, and determinants of exposure were estimated using multilevel mixed-effects tobit regression analyses. Time trends were estimated for sampling duration below and above 8 h, both overall and for job groups. The variability of exposure between installation and workers was investigated in a subset of data containing worker identification.ResultsThe overall GM of benzene exposure was 0.004 ppm. When adjusting for job group, design of process area, season, wind speed, and sampling duration, industrial cleaners had the highest exposure (GM = 0.012). Laboratory technicians, mechanics, and process operators had a GM exposure of 0.004, 0.003, and 0.004 ppm, respectively. Overall, the measured benzene exposure increased by 7.6% per year from 2002 to 2018. Mechanics had an annual increase of 8.6% and laboratory technicians had an annual decrease of 12.6% when including all measurements. When including only measurements above 8 h, mechanics had an increase of 16.8%. No statistically significant time trend was found for process operators. Open process area, high wind speed, and wintertime were associated with reduced exposure level.ConclusionsAn overall increase in measured exposure was observed from 2002 to 2018. The increase may reflect changes in measurement strategy from mainly measuring on random days to days with expected exposure. However, the time trend varied between job groups and was different for sampling duration above or below 8 h. Industrial cleaners had the highest exposure of the four job groups while no differences in exposure were observed between laboratory technicians, mechanics, and process operators. The design of the process area, job group, wind speed, and season were all significant determinants of benzene exposure.

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.

Epigenetic aging biomarkers and occupational exposure to benzene, trichloroethylene and formaldehyde

Epigenetic aging biomarkers are associated with increased morbidity and mortality. We evaluated if occupational exposure to three established chemical carcinogens is associated with acceleration of epigenetic aging. We studied workers in China occupationally exposed to benzene, trichloroethylene (TCE) or formaldehyde by measuring personal air exposures prior to blood collection. Unexposed controls matched by age and sex were selected from nearby factories. We measured leukocyte DNA methylation (DNAm) in peripheral white blood cells using the Infinium HumanMethylation450 BeadChip to calculate five epigenetic aging clocks and DNAmTL, a biomarker associated with leukocyte telomere length and cell replication. We tested associations between exposure intensity and epigenetic age acceleration (EAA), defined as the residuals of regressing the DNAm aging biomarker on chronological age, matching factors and potential confounders. Median differences in EAA between exposure groups were tested using a permutation test with exact p-values. Epigenetic clocks were strongly correlated with age (Spearman r > 0.8) in all three occupational studies. There was a positive exposure-response relationship between benzene and the Skin-Blood Clock EAA biomarker: median EAA was −0.91 years in controls (n = 44), 0.78 years in workers exposed to <10 ppm (n = 41; mean benzene = 1.35 ppm; p = 0.034 vs. controls), and 2.10 years in workers exposed to ≥10 ppm (n = 9; mean benzene = 27.3 ppm; p = 0.019 vs. controls; ptrend = 0.0021). In the TCE study, control workers had a median Skin-Blood Clock EAA of −0.54 years (n = 71) compared to 1.63 years among workers exposed to <10 ppm of TCE (n = 27; mean TCE = 4.22 ppm; p = 0.035). We observed no evidence of EAA associations with formaldehyde exposure (39 controls, 31 exposed). Occupational benzene and TCE exposure were associated with increased epigenetic age acceleration measured by the Skin-Blood Clock. For TCE, there was some evidence of epigenetic age acceleration for lower exposures compared to controls. Our results suggest that some chemical carcinogens may accelerate epigenetic aging.

A Quantitative Meta-Analysis of the Relation between Occupational Benzene Exposure and Biomarkers of Cytogenetic Damage.

Background:The genotoxicity of benzene has been investigated in dozens of biomonitoring studies, mainly by studying (classical) chromosomal aberrations (CAs) or micronuclei (MN) as markers of DNA damage. Both have been shown to be predictive of future cancer risk in cohort studies and could, therefore, potentially be used for risk assessment of genotoxicity-mediated cancers.Objectives:We sought to estimate an exposure–response curve (ERC) and quantify between-study heterogeneity using all available quantitative evidence on the cytogenetic effects of benzene exposure on CAs and MN respectively.Methods:We carried out a systematic literature review and summarized all available data of sufficient quality using meta-analyses. We assessed the heterogeneity in slope estimates between studies and conducted additional sensitivity analyses to assess how various study characteristics impacted the estimated ERC.Results:Sixteen CA (1,356 individuals) and studies (2,097 individuals) were found to be eligible for inclusion in a meta-analysis. Studies where benzene was the primary genotoxic exposure and that had adequate assessment of both exposure and outcomes were used for the primary analysis. Estimated slope estimates were an increase of 0.27% CA [(95% CI: 0.08%, 0.47%); based on the results from 4 studies] and 0.27% MN [(95% CI: , 0.76%); based on the results from 7 studies] per parts-per-million benzene exposure. We observed considerable between-study heterogeneity for both end points ().Discussion:Our study provides a systematic, transparent, and quantitative summary of the literature describing the strong association between benzene exposure and accepted markers of genotoxicity in humans. The derived consensus slope can be used as a best estimate of the quantitative relationship between real-life benzene exposure and genetic damage in future risk assessment. We also quantitate the large between-study heterogeneity that exists in this literature, a factor which is crucial for the interpretation of single-study or consensus slopes. https://doi.org/10.1289/EHP6404

Occupational benzene exposure and the risk of genetic damage: a systematic review and meta-analysis

BackgroundBenzene, an important component of organic solvents, is commonly used in industry. Meanwhile, benzene is a human carcinogen leading to leukemia. Although the links between benzene and various types of genetic damage indicators have been evaluated in several studies, but their results remain inconsistent. So we conducted a meta-analysis, and to explore the influence of low concentration benzene exposure on workers’ genetic damage indicators using 3.25 mg/m3 as the boundary value, in order to provide a basis for improved prevention and control of the harm from benzene exposure to the occupational population.MethodsWe conducted a search of five databases, including Pub Med, Web of Science, China National Knowledge Infrastructure (CNKI), Wan Fang Data and Chongqing VIP, to identify relevant articles up to December 25, 2018. Two researchers independently extracted and evaluated the data according to the inclusion and exclusion criteria of the literature. The imported articles were managed by Endnote X7, and the data were extracted and sorted by Excel 2013. We utilized Stata 12.0 software to perform the meta-analysis in the present study.ResultsA total of 68 eligible articles were finally included for the synthetic analyses. The meta-analysis results showed that occupational benzene exposure led to significantly increased Micronucleus (MN) frequency, Sister chromatid exchange (SCE) frequency, Chromosome aberration (CA) frequency, Olive Tail moment (OTM), Tail moment (TM), Tail length (TL), and Tail DNA% (T DNA%) compared to the control group (P < 0.05), and the pooled effect value estimates were 1.36, 0.98, 0.76, 1.06, 0.96, 1.78, and 1.42, respectively. Subsequent analysis of the effect of low concentration benzene exposure on genetic damage found significantly increased MN frequency increased compared with the control group (P < 0.05).ConclusionsOccupational benzene exposure can affect multiple genetic damage indicators. Even at an exposure concentration lower than 3.25 mg/m3, benzene exposure has genotoxicity. These data provide an important scientific basis for the further revision of occupational disease prevention strategies. At the same time, increased attention should be focused on the health monitoring of the occupational population exposed to benzene, and health management should be strengthened to improve the health of the occupational population.

Association of Urinary Phenol Concentration and Blood Biochemical Indices in Coke Oven Workers

Objective: To explore the association of urinary phenol concentration and blood biochemical indices in coke oven workers. Methods: From April to may 2019, we investigated 771 employing coke oven workers from a coke plant in Taiyuan city, and categorized into benzene-exposed group (n=402) and control group (n=369) based on their benzene exposures in workplace and urophenol concentrations. All subjects were interviewed face-to-face using a questionnaire including name, age (year) , gender, smoking and drinking habits, personal vocational history, working length (year) , and occupational protection, etc. Post-shift urine samples detected using a gas chromatography-hydrogen flame ionization detector. Fasting venous blood was drawn in the morning and centrifuged, the separated serum were detected the following items using an automatic blood biochemistry analyzer. Covariance and multiple linear regression were used to test the association of urinary phenol concentration and the levels of all the blood biochemical indices. Results: The subjects were predominantly males (n=719, 93.3%) , with an average age of (42.3±8.2) years and an average working length of (20.6±8.2) years. Compared with the control group, the benzene-exposed group were significantly different in age, working length of years, gender, smoking and drinking habits (P<0.05) . The median (interquartile interval) concentration of urinary phenol was 6.00 (0.00-33.00) μg/ml in the benzene-exposed group, which was significantly higher than that in the control group (P<0.05) . Covariance analysis indicated that the fasting blood glucose, total cholesterol and high density cholesterol in the benzene-exposed group were significantly reduced compared with the control group, yet the serum creatinine, serum uric acid and triglyceride were significantly increased (P<0.05) . Multiple linear regression showed that, an increase of each natural logarithm (Ln) transformed urinary phenol concentration was significantly associated with increases in serum uric acid level [9.82 (95%CI: 2.18-17.47) μmol/L] and cholesterol level[0.10 (95%CI:0.00-0.20) mmol/L]. An increase of each Ln-transformed accumulated benzene exposure levels was significantly associated with an increase in total cholesterol level[0.09 (95%CI: 0.01-0.17) mmol/L]. Conclusion: Occupational benzene exposure is possibly related to the variation of purine and total cholesterol metabolism in coke oven workers.

Investigation on the health status of workers exposed to benzene in one province

Objective: To explore the health status of occupational benzene exposure workers, and to provide a scientific basis for the development of reasonable health monitoring and effective protective measures. Methods: In March 2019, the occupational health surveillance data were collected including blood pressure, electrocardiogram, blood routine, urine routine, liver function, etc of 7810 benzene contact workers in 150 enterprises in Jiangxi Province in 2017, to analyze and assess their health status. Results: Among the 7810 benzene workers, there were 5451 males and 2359 females; the average age was (40.5±9.9) years; and the median benzene working age was 3.5 years. The detection rate of hypertension was 17.0% (734/4317) , the abnormal rate of urine routine was 15.7% (1227/7810) , the abnormal rate of liver function was 8.6% (356/4147) , and the abnormal rate of electrocardiogram was 12.3%(963/7810). The detection rates of low count number of leukocytes, platelets, neutrophils and occupational contraindications were 4.6%(360/7810) , 1.4%(108/7810) , 4.2%(330/7810) and 1.4%(110/7810) , respectively. The detection rates of low count number of leukocytes, platelets and neutrophils in female were all higher than those in male (P<0.05). The detection rates of low count number of platelets, neutropenia and occupational contraindications increased with age and working age (P<0.05 ). There were significant differences in the detection rates of low count number of leukocytes, platelets, neutrophils and occupational contraindications among benzene workers in different economic types (P<0.05) , and the highest among foreign companies, followed by private enterprise. There were statistically significant differences in the detection rates of low count number of platelets, neutrophils and occupational contraindications in benzene workers of different enterprise sizes (P<0.05) , and the highest was found in micro enterprises, followed by small enterprises. Conclusion: In 2017, the occupational health status of workers exposed to benzene in Jiangxi province is not optimistic. It is necessary to strengthen the occupational health supervision of small and micro-sized enterprises, foreign enterprises and private enterprises, take the initiative to improve health surveillance, and effectively protect the physical and mental health of workers.

Characteristics in the Distribution of Chronic Benzene Poisoning Associated Industries - 6 PLADs, China, 2005-2019.

What is already known on this topic? Starting in the early 1950s, the main industries in China associated with chronic benzene poisoning (CBP) included painting, pharmaceuticals, and shoemaking. However, because of rapid socioeconomic development, the distribution of industries associated with CBP likely changed. What is added by this report? From 2005 to 2019, CBP has become an increasingly important type of chronic occupational poisoning (COP) in China. CBP was mainly found to have occurred in manufacturing industries, especially private enterprises and small and medium-sized enterprises. The sub-industry with the highest proportion of CBP cases was general and special equipment manufacturing, followed by chemical raw materials and chemical manufacturing. What are the implications for public health practice? CBP was found to be the main component of COP in China, so the supervision and management in manufacturing, especially in the medium-sized and small enterprises, need to be strengthened. Occupational benzene exposure limits should also be adjusted accordingly.

A meta-analysis to assess the quantitative relationship between occupational benzene exposure and biomarkers of genetic damage (chromosomal aberrations and micronuclei)

A meta-analysis to assess the quantitative relationship between occupational benzene exposure and biomarkers of genetic damage (chromosomal aberrations and micronuclei)

Association of a Giant Lymphoma Mass With Occupational Benzene Exposure

Benzene is a chemical widely used in industrial settings and known to have hematopoietic toxicity. Previous literature has been inconsistent regarding a direct association of benzene exposure with lymphoma. A young patient with a strong history of benzene exposure presented with a 17-cm chest wall lymphoma and purulent drainage from the mass. He underwent resection of the mass. Pathologic analysis revealed a high-grade diffuse large B-cell lymphoma. The wound ultimately healed well and the patient received adjuvant chemotherapy. Though the overall literature has been inconsistent regarding the association of benzene with lymphoma, our report highlights the possibility that a very extensive exposure history may be a risk factor for the development of lymphoma. J Med Cases. 2019;10(9):274-276 doi: https://doi.org/10.14740/jmc3364

Estimation of Source-Specific Occupational Benzene Exposure in a Population-Based Case-Control Study of Non-Hodgkin Lymphoma.

Occupational exposures in population-based case-control studies are increasingly being assessed using decision rules that link participants' responses to occupational questionnaires to exposure estimates. We used a hierarchical process that incorporated decision rules and job-by-job expert review to assign occupational benzene exposure estimates in a US population-based case-control study of non-Hodgkin lymphoma. We conducted a literature review to identify scenarios in which occupational benzene exposure has occurred, which we grouped into 12 categories of benzene exposure sources. For each source category, we then developed decision rules for assessing probability (ordinal scale based on the likelihood of exposure > 0.02 ppm), frequency (proportion of work time exposed), and intensity of exposure (in ppm). The rules used the participants' occupational history responses and, for a subset of jobs, responses to job- and industry-specific modules. For probability and frequency, we used a hierarchical assignment procedure that prioritized subject-specific module information when available. Next, we derived job-group medians from the module responses to assign estimates to jobs with only occupational history responses. Last, we used job-by-job expert review to assign estimates when job-group medians were not available or when the decision rules identified possible heterogeneous or rare exposure scenarios. For intensity, we developed separate estimates for each benzene source category that were based on published measurement data whenever possible. Frequency and intensity annual source-specific estimates were assigned only for those jobs assigned ≥75% probability of exposure. Annual source-specific concentrations (intensity × frequency) were summed to obtain a total annual benzene concentration for each job. Of the 8827 jobs reported by participants, 8% required expert review for one or more source categories. Overall, 287 (3.3%) jobs were assigned ≥75% probability of exposure from any benzene source category. The source categories most commonly assigned ≥75% probability of exposure were gasoline and degreasing. The median total annual benzene concentration among jobs assigned ≥75% probability was 0.11 ppm (interquartile range: 0.06-0.55). The highest source-specific median annual concentrations were observed for ink and printing (2.3 and 1.2 ppm, respectively). The applied framework captures some subject-specific variability in work tasks, provides transparency to the exposure decision process, and facilitates future sensitivity analyses. The developed decision rules can be used as a starting point by other researchers to assess occupational benzene exposure in future population-based studies.