Review of occupational lung carcinogens

Lung cancer survival among Florida male firefighters

Introduction

Lung cancer is a leading cause of cancer incidence and death in the United States. Although most firefighters are fit and do not smoke, they are exposed to many known carcinogens during and in the aftermath of firefighting activities. Comprehensive epidemiologic investigations on lung cancer survival for both career and volunteer firefighters have not been undertaken.

Methods

Data from the Florida Cancer Data System (1981-2014) were linked with firefighter certification records from the Florida State Fire Marshal's Office to identify all patients of this occupational group; lung cancer cause-specific survival data were compared with other occupational groups using Cox regression models with occupation as the main effect. Adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI) were calculated.

Results

Out of 210,541 male lung cancer cases diagnosed in Florida (1981-2014), 761 were firefighters (604 career, 157 volunteer). Lung cancer death was similar between volunteer (75.2%) and career firefighters (74.0%) but lower than non-firefighters (80.0%). Survival at 5 years was higher among firefighters (29.7%; career: 30.3%; volunteer: 27.4%) than non-firefighters (23.8%). In a multivariable model, compared with non-firefighters, firefighters have significantly higher cause-specific survival (aHR = 0.84; 95% CI: 0.77-0.91; p < 0.001). However, there were no significant survival differences between career and volunteer firefighters (1.14; 0.93-1.39; p = 0.213). In a separate multivariable model with firefighters as the comparator, other broad occupational groups had significantly lower cause-specific survival [white collar: 1.11 (1.02-1.21); blue collar: 1.15 (1.05-1.25); service: 1.13 (1.03-1.25); others/unknown: 1.21 (1.12-1.32); all p-values < 0.02].

Conclusion

Lung cancer survival is significantly higher among firefighters compared with non-firefighters, but there is no significant difference between career and volunteer firefighters. Improved survival for firefighters might be due to a healthy worker effect, lower smoking prevalence relative to other worker groups, and possibly superior treatment adherence and compliance. Many firefighters are cross-trained as EMTs/paramedics and possess a level of medical knowledge that may favorably impact treatment engagement and better navigation of complex cancer care.

Predictive value of a novel Asian lung cancer screening nomogram based on artificial intelligence and epidemiological characteristics

Background

To develop and validate a risk prediction nomogram based on a deep learning convolutional neural networks (CNN) model and epidemiological characteristics for lung cancer screening in patients with small pulmonary nodules (SPN).

Methods

This study included three data sets. First, a CNN model was developed and tested on data set 1. Then, a hybrid prediction model was developed on data set 2 by multivariable binary logistic regression analysis. We combined the CNN model score and the selected epidemiological risk factors, and a risk prediction nomogram was presented. An independent multicenter cohort was used for model external validation. The performance of the nomogram was assessed with respect to its calibration and discrimination.

Results

The final hybrid model included the CNN model score and the screened risk factors included age, gender, smoking status and family history of cancer. The nomogram showed good discrimination and calibration with an area under the curve (AUC) of 91.6% (95% CI: 89.4%–93.5%), compare with the CNN model, the improvement was significance. The performance of the nomogram still showed good discrimination and good calibration in the multicenter validation cohort, with an AUC of 88.3% (95% CI: 83.1%–92.3%).

Conclusions

Our study showed that epidemiological characteristics should be considered in lung cancer screening, which can significantly improve the efficiency of the artificial intelligence (AI) model alone. We combined the CNN model score with Asian lung cancer epidemiological characteristics to develop a new nomogram to facilitate and accurately perform individualized lung cancer screening, especially for Asians.

Predicting Lung Cancer in the United States: A Multiple Model Examination of Public Health Factors

In this research, we take a multivariate, multi-method approach to predicting the incidence of lung cancer in the United States. We obtain public health and ambient emission data from multiple sources in 2000–2013 to model lung cancer in the period 2013–2017. We compare several models using four sources of predictor variables: adult smoking, state, environmental quality index, and ambient emissions. The environmental quality index variables pertain to macro-level domains: air, land, water, socio-demographic, and built environment. The ambient emissions consist of Cyanide compounds, Carbon Monoxide, Carbon Disulfide, Diesel Exhaust, Nitrogen Dioxide, Tropospheric Ozone, Coarse Particulate Matter, Fine Particulate Matter, and Sulfur Dioxide. We compare various models and find that the best regression model has variance explained of 62 percent whereas the best machine learning model has 64 percent variance explained with 10% less error. The most hazardous ambient emissions are Coarse Particulate Matter, Fine Particulate Matter, Sulfur Dioxide, Carbon Monoxide, and Tropospheric Ozone. These ambient emissions could be curtailed to improve air quality, thus reducing the incidence of lung cancer. We interpret and discuss the implications of the model results, including the tradeoff between transparency and accuracy. We also review limitations of and directions for the current models in order to extend and refine them.

A Population-Based Feasibility Study of Occupation and Thoracic Malignancies in New Mexico

Background

Occupational exposures in mining and oil/gas extraction are known risk factors for thoracic malignancies (TMs). Given the relatively high proportion of these industries in New Mexico (NM), we conducted a feasibility study of adult lifetime occupational history among TM cases. We hypothesized a higher proportion of occupational TM in NM relative to the estimated national average of 10-14%.

Methods

We identified incident TM cases through the population-based New Mexico Tumor Registry (NMTR), from 2017-2018. Cases completed a telephone interview. An adjudication panel reviewed case histories and classified cancers as probable, possible, or non-occupational related, taking into account the presence, duration, and latency of exposures. We characterized recruitment and describe job titles and exposures among those with occupational TMs. We also compared the distributions of industry between those with and without occupational TM.

Results

The NMTR identified 400 eligible TM cases, 290 of which were available to be recruited (n=285 lung/bronchial cancer; n=5 mesotheliomas). Of the latter, 60% refused and 18% were deceased, 9% had invalid addresses, 11% were unable to be reached by telephone, and 3% were too ill to participate. The 43 cases who completed an interview held 236 jobs. A total of 33% of cases were classified as probable occupational TM and 5% as possible occupational TM.

Conclusions

High rates of early mortality and refusals were significant barriers to study participation. Nonetheless, the proportion of probable occupational TMs greatly exceeded the estimated national average, highlighting the need for further study of occupational TM in the state.

Performance of Risk Factor-Based Guidelines and Model-Based Chest CT Lung Cancer Screening in World Trade Center-Exposed Fire Department Rescue/Recovery Workers

BACKGROUND

Lung cancer is a leading cause of cancer incidence and death in the United States. Risk factor-based guidelines and risk model-based strategies are used to identify patients who could benefit from low-dose chest CT (LDCT) screening. Few studies compare guidelines or models within the same cohort. We evaluate lung cancer screening performance of two risk factor-based guidelines (US Preventive Services Task Force 2014 recommendations [USPSTF-2014] and National Comprehensive Cancer Network Group 2 [NCCN-2]) and two risk model-based strategies, Prostate Lung Colorectal and Ovarian Cancer Screening (PLCOm2012) and the Bach model) in the same occupational cohort.

RESEARCH QUESTION

Which risk factor-based guideline or model-based strategy is most accurate in detecting lung cancers in a highly exposed occupational cohort?

STUDY DESIGN AND METHODS

Fire Department of City of New York (FDNY) rescue/recovery workers exposed to the September 11, 2001 attacks underwent LDCT lung cancer screening based on smoking history and age. The USPSTF-2014, NCCN-2, PLCOm2012 model, and Bach model were retrospectively applied to determine how many lung cancers were diagnosed using each approach.

RESULTS

Among the study population (N = 3,953), 930 underwent a baseline scan that met at least one risk factor or model-based LDCT screening strategy; 73% received annual follow-up scans. Among the 3,953, 63 lung cancers were diagnosed, of which 50 were detected by at least one LDCT screening strategy. The NCCN-2 guideline was the most sensitive (79.4%; 50/63). When compared with NCCN-2, stricter age and smoking criteria reduced sensitivity of the other guidelines/models (USPSTF-2014 [44%], PLCOm2012 [51%], and Bach[46%]). The 13 missed lung cancers were mainly attributable to smoking less and quitting longer than guideline/model eligibility criteria. False-positive rates were similar across all four guidelines/models.

INTERPRETATION

In this cohort, our findings support expanding eligibility for LDCT lung cancer screening by lowering smoking history from ≥30 to ≥20 pack-years and age from 55 years to 50 years old. Additional studies are needed to determine its generalizability to other occupational/environmental exposed cohorts.

Lung Cancer Screening: Patient Selection and Implementation

Robust evidence exists in support of lung cancer (LC) screening with low-dose computed tomography in patients at high risk of developing LC; however, judicious patient selection is necessary to obtain optimal benefit while minimizing harm. Several professional societies have published recommendations regarding patient selection criteria for screening. Multiple risk prediction models that include additional patient-specific risk factors have since been developed to more accurately predict risk of developing LC. Implementation of a new screening program requires thorough multidisciplinary planning and maintenance. Multisociety guidelines highlight 9 principal components to implement and maintain a successful program.

[Tobacco and work]

INTRODUCTION

Health indicators published over more than 15 years in France show differences in the prevalence of smoking in relation to activity status and socio-professional categories. However, the relationship between smoking and work is not limited to this.

BACKGROUND

Smoking by employees is traditionally regarded as entailing additional costs for businesses, but the actual costs of smoking in the workplace are difficult to assess. Co-exposure to tobacco and the toxic substances encountered in work areas carries an increased risk of developing lung disease, broncho-pulmonary cancer and chronic obstructive pulmonary disease in particular. The workplace can also be an area of exposure to passive smoking that affects employees unequally. In France, the use of tobacco and e-cigarettes in the workplace has been regulated since 2006 and 2016, respectively.

OUTLOOK

Workplace smoking cessation programs and smoking bans seem to encourage cessation of smoking. Smoking cessation advice by occupational physicians could work in the same manner. Subjects exposed to occupational carcinogens and tobacco could benefit from low-dose CT screening after a trial period to validate this approach.

CONCLUSION

Workplaces can be areas for the prevention and cessation of smoking.

Lung cancer risk and do-it-yourself activities. A neglected risk factor for lung cancer

BACKGROUND

The aim of this study was to assess the relationship between do-it-yourself activities entailing the exposure to carcinogenic substances and the risk of lung cancer.

METHODS

We pooled individual data from different case-control studies conducted in Northwestern Spain which investigated residential radon and lung cancer. Cases had an anatomopathologically confirmed primary lung cancer and controls were selected at the pre-surgery unit with uncomplicated surgeries. Both cases and controls were older than 30 years with no previous cancer history. All participants were interviewed face-to-face using a specific questionnaire. Painting, model building, furniture refinishing and woodworking or home carpentry were the do-it-yourself activities considered risky due to exposure to carcinogenic agents.

RESULTS

We included 1528 cases and 1457 controls. Practicing do-it-yourself risk activities was more frequent among cases: 16.0% were exposed to carcinogenic exposures during leisure time, compared to 11.8% for controls. The overall adjusted OR for lung cancer risk among individuals who practiced do-it-yourself risk activities, was 1.77 (95% CI: 1.36-2.31); this was 2.17 (95% CI: 1.51-3.11) when the analysis was restricted to individuals who performed these activities for at least 10 years. These risks were greater when the analyses were carried out exclusively among never-smokers, with the respective ORs being 2.04 (95% CI: 1.38-3.01) and 3.10 (95% CI: 1.78-5.40).

CONCLUSION

These results support the hypothesis that do-it-yourself activities involving exposure to certain carcinogens are associated with an increased risk of lung cancer, both in ever and never-smokers.

Lung Cancer Screening, Version 3.2018, NCCN Clinical Practice Guidelines in Oncology

Lung cancer is the leading cause of cancer-related mortality in the United States and worldwide. Early detection of lung cancer is an important opportunity for decreasing mortality. Data support using low-dose computed tomography (LDCT) of the chest to screen select patients who are at high risk for lung cancer. Lung screening is covered under the Affordable Care Act for individuals with high-risk factors. The Centers for Medicare & Medicaid Services (CMS) covers annual screening LDCT for appropriate Medicare beneficiaries at high risk for lung cancer if they also receive counseling and participate in shared decision-making before screening. The complete version of the NCCN Guidelines for Lung Cancer Screening provides recommendations for initial and subsequent LDCT screening and provides more detail about LDCT screening. This manuscript focuses on identifying patients at high risk for lung cancer who are candidates for LDCT of the chest and on evaluating initial screening findings.

Association between the risk of lung cancer and influenza: A population-based nested case-control study

BACKGROUND

Previous animal studies have shown that certain respiratory oncoviruses can lead to tumorigenesis, especially influenza virus. However, no clinical studies other than animal studies have been conducted to test this hypothesis.

OBJECTIVE

To investigate the association between influenza and the risk of lung cancer using the Taiwan Cancer Registry Database (TCRD) and Taiwan's National Health Insurance Research Database (NHIRD).

METHODS

We identified a study cohort consisting of patients aged 40 years or above who were enrolled in the NHIRD between 1 January 2012 and 31 December 2014. Among them, we identified patients with lung cancer (cases) and their matched controls (matched by age, sex, and disease risk score (DRS) at a ratio of 1:10). Multivariate conditional logistic regression models were used to evaluate the association between exposure to influenza (timing and cumulative number) and risk of lung cancer.

RESULTS

We identified 32,063 cases and 320,627 matched controls. Influenza was associated with a 1.09-fold increased risk of lung cancer (aOR 1.09, 95% CI 1.04-1.14, p<0.0001). The risk of lung cancer increased slightly with cumulative exposure to influenza (1-2 exposures: aOR 1.05, 95% CI 1.00-1.11; 3-4 exposures: aOR 1.12, 95% CI 1.00-1.25; 5+ exposures: aOR 1.25, 95% CI 1.13-1.39).

CONCLUSION

Exposure to influenza was associated with an increased risk of lung cancer and the risk increased with cumulative exposure to influenza. However, the lack of valid information on smoking could lead to confounding, and future studies collecting patients' smoking histories are warranted to validate the association between influenza and lung cancer.

A case-control study of trace-element status and lung cancer in Appalachian Kentucky

Appalachian Kentucky (App KY) leads the nation in lung cancer incidence and mortality. Trace elements, such as As, have been associated with lung cancers in other regions of the country and we hypothesized that a population-based study would reveal higher trace element concentrations in App KY individuals with cancer compared to controls. Using toenail and drinking water trace element concentrations, this study investigated a possible association between lung cancer incidence and trace-element exposure in residents of this region. This population-based case-control study had 520 subjects, and 367 subjects provided toenail samples. Additionally, we explored the relationship between toenail and fingernail trace-element concentrations to determine if fingernails could be used as a surrogate for toenails when patients are unable to provide toenail samples. We found that, contrary to our initial hypothesis, trace element concentrations (Al, As, Cr, Mn, Co, Fe, Ni, Cu, Se, and Pb) were not higher in cancer cases than controls with the exception of Zn where concentrations were slightly higher in cases. In fact, univariate logistic regression models showed that individuals with lower concentrations of several elements (Al, Mn, Cr, and Se) were more likely to have lung cancer, although only Mn was significant in multivariate models which controlled for confounding factors. While drinking water concentrations of Al, Cr and Co were positively related to cancer incidence in univariate models, only Co remained significant in multivariate models. However, since the drinking water concentrations were extremely low and not reflected in the toenail concentrations, the significance of this finding is unclear. We also found that fingernail concentrations were not consistently predictive of toenail concentrations, indicating that fingernails should not be used as surrogates for toenails in future studies.

Burden of lung cancer attributable to occupational diesel engine exhaust exposure in Canada

Objective

To estimate the population attributable fraction (PAF) and number of incident and fatal lung cancers in Canada from occupational exposure to diesel engine exhaust (DEE).

Methods

DEE exposure prevalence and level estimates were used with Canadian Census and Labour Force Survey data to model the exposed population across the risk exposure period (REP, 1961–2001). Relative risks of lung cancer were calculated based on a meta-regression selected from the literature. PAFs were calculated using Levin’s equation and applied to the 2011 lung cancer statistics obtained from the Canadian Cancer Registry.

Results

We estimated that 2.4% (95% CI 1.6% to 6.6%) of lung cancers in Canada are attributable to occupational DEE exposure, corresponding to approximately 560 (95% CI 380 to 1570) incident and 460 (95% CI 310 to 1270) fatal lung cancers in 2011. Overall, 1.6 million individuals alive in 2011 were occupationally exposed to DEE during the REP, 97% of whom were male. Occupations with the highest burden were underground miners, truck drivers and mechanics. Half of the attributable lung cancers occurred among workers with low exposure.

Conclusions

This is the first study to quantify the burden of lung cancer attributable to occupational DEE exposure in Canada. Our results underscore a large potential for prevention, and a large public health impact from occupational exposure to low levels of DEE.

Epidemiology of Lung Cancer

Lung cancer has been transformed from a rare disease into a global problem and public health issue. The etiologic factors of lung cancer become more complex along with industrialization, urbanization, and environmental pollution around the world. Currently, the control of lung cancer has attracted worldwide attention. Studies on the epidemiologic characteristics of lung cancer and its relative risk factors have played an important role in the tertiary prevention of lung cancer and in exploring new ways of diagnosis and treatment. This article reviews the current evolution of the epidemiology of lung cancer.

The decline in kidney function with chromium exposure is exacerbated with co-exposure to lead and cadmium

Environmental factors contribute significantly to the pathogenesis of chronic kidney disease. However, these factors, and particularly the toxic effects of heavy metals, have not been completely evaluated. Chromium is a widespread industrial contaminant that has been linked to nephrotoxicity in animal and occupational population studies. Nevertheless, its role in population renal health and its potential interactions with other nephrotoxic metals, such as lead and cadmium, remain unknown. We assessed the association between exposure to chromium, lead, and cadmium with renal function using estimated glomerular filtration rate (eGFR) in an analysis of 360 Taiwanese adults aged 19-84 years from the National Nutrition and Health Survey in Taiwan (2005-2008). Doubling of urinary chromium or lead decreased the eGFR by -5.99 mL/min/1.73 m² (95% confidence interval -9.70, -2.27) and -6.61 (-9.71, -3.51), respectively, after adjusting for age, sex, body mass index, hypertension, diabetes, cigarette smoking, sodium intake, education, urinary volume, and other metals. For those in the highest tertile of cadmium exposure, the eGFR decreased by -12.68 mL/min/1.73 m² (95% confidence interval -20.44, -4.93) and -11.22 mL/min/1.73 m² (-17.01, -5.44), as urinary chromium or lead levels doubled, respectively. Thus, there is a significant and independent association between chromium exposure and decreased renal function. Furthermore, co-exposure to chromium with lead and cadmium is potentially associated with additional decline in the glomerular filtration rate in Taiwanese adults.

Medical follow-up of workers exposed to lung carcinogens: French evidence-based and pragmatic recommendations

Background

The aim of this work was to establish recommendations for the medical follow-up of workers currently or previously exposed to lung carcinogens.

Methods

A critical synthesis of the literature was conducted. Occupational lung carcinogenic substances were listed and classified according to their level of lung cancer risk. A targeted screening protocol was defined.

Results

A clinical trial, National Lung Screnning Trial (NLST), showed the efficacy of chest CAT scan (CT) screening for populations of smokers aged 55–74 years with over 30 pack-years of exposure who had stopped smoking for less than 15 years. To propose screening in accordance with NLST criteria, and to account for occupational risk factors, screening among smokers and former smokers needs to consider the types of occupational exposure for which the risk level is at least equivalent to the risk of the subjects included in the NLST. The working group proposes an algorithm that estimates the relative risk of each occupational lung carcinogen, taking into account exposure to tobacco, based on available data from the literature.

Conclusion

Given the lack of data on bronchopulmonary cancer (BPC) screening in occupationally exposed workers, the working group proposed implementing a screening experiment for bronchopulmonary cancer in subjects occupationally exposed or having been occupationally exposed to lung carcinogens who are confirmed as having high risk factors for BPC. A specific algorithm is proposed to determine the level of risk of BPC, taking into account the different occupational lung carcinogens and tobacco smoking at the individual level.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4114-1) contains supplementary material, which is available to authorized users.

Modification of association between prior lung disease and lung cancer by inhaled arsenic: A prospective occupational-based cohort study in Yunnan, China

Arsenic and prior lung diseases have been shown to increase lung cancer risk; however, little is known about their joint effects. The aim of our study was to analyze the joint effects of inhaled arsenic and prior lung diseases on lung cancer risk within a occupational cohort. The interactions of prior lung diseases and inhaled arsenic were analyzed based on multiplicative and additive scales in the Cox proportional hazards model. Compared with low arsenic exposure and no history of asthma, the hazard ratios (HRs) of high arsenic exposure with asthma, high arsenic exposure without asthma and low arsenic exposure with asthma were 2.61 (95% CI: 1.71-4.00), 2.60 (95% CI: 1.93-3.51) and 2.49 (95% CI: 1.53-4.06), respectively. Based on the multiplicative scale in the Cox proportional hazards model, the HR of the interaction of asthma and arsenic on lung cancer risk was 0.45 (95% CI: 0.25-0.80). Based on the additive scale, the relative excess risk due to interaction between asthma and arsenic was -1.41 (95% CI: -2.81 to -0.02). Our study provides strong evidence that arsenic exposure is associated with lung cancer risk. A significant negative interaction between asthma and arsenic on lung cancer risk is observed.

Bladder cancer and occupational exposure to diesel and gasoline engine emissions among Canadian men

The International Agency for Research on Cancer has classified diesel exhaust as a carcinogen based on lung cancer evidence; however, few studies have investigated the effect of engine emissions on bladder cancer. The purpose of this study was to investigate the association between occupational exposure to diesel and gasoline emissions and bladder cancer in men using data from the Canadian National Enhanced Cancer Surveillance System; a population‐based case–control study. This analysis included 658 bladder cancer cases and 1360 controls with information on lifetime occupational histories and a large number of possible cancer risk factors. A job‐exposure matrix for engine emissions was supplemented by expert review to assign values for each job across three dimensions of exposure: concentration, frequency, and reliability. Odds ratios (OR) and their corresponding 95% confidence intervals were estimated using logistic regression. Relative to unexposed, men ever exposed to high concentrations of diesel emissions were at an increased risk of bladder cancer (OR = 1.64, 0.87–3.08), but this result was not significant, and those with >10 years of exposure to diesel emissions at high concentrations had a greater than twofold increase in risk (OR = 2.45, 1.04–5.74). Increased risk of bladder cancer was also observed with >30% of work time exposed to gasoline engine emissions (OR = 1.59, 1.04–2.43) relative to the unexposed, but only among men that had never been exposed to diesel emissions. Taken together, our findings support the hypothesis that exposure to high concentrations of diesel engine emissions may increase the risk of bladder cancer.

[Complications of metal-on-metal tribological pairing]

BACKGROUND

Metal-on-metal (MoM) tribological pairing results in less volumetric abrasion than pairing with the conventionally used polyethylene and is associated with a lower risk of material failure compared to other hard-hard pairings. An increased frequency of problem cases in recent years has led to a great increase in uncertainty. Against this background in this article the current aspects of epidemiology, etiology, diagnostics and treatment of complications in MoM hip joint endoprostheses will be discussed.

EPIDEMIOLOGY AND ETIOLOGY

Based on the results from national endoprosthesis registers and selected clinical studies an evaluation of the rate of local complications from MoM tribological pairings was undertaken. A differentiation was made between MoM pairings in pedicled small head prostheses (≤ 32 mm), large head (> 32 mm) and surface replacement (OFE) endoprostheses. Each year MoM endoprostheses release on average 10(12)-10(14) cobalt (Co) and chromium (Cr) nanoparticles per patient. This release of metal ions and particles can lead to a variety of tissue reactions.

DIAGNOSTICS

A differentiation must be made between regular routine diagnostics within the framework of implant follow-up screening and specific investigations due to the occurrence of complaints. The diagnostics for patients treated with MoM hip endoprostheses consists of a standardized step-wise approach considering possible differential diagnoses and the utilization of modern laboratory chemical and radiological methods. When problems occur, a differentiation should preferentially be made between complaints not caused by metal and mechanical problems (e.g. prosthesis loosening and impingement) and symptoms due to periprosthetic infections.

THERAPY OF COMPLICATIONS

The normal standards for hip endoprosthetics are also valid for periprosthetic infections, fractures and other general complications. Specific measures are, however, necessary for complications due to metal-specific risks.

Estimating the social cost of respiratory cancer cases attributable to occupational exposures in France

PURPOSE

The objective of this article was to estimate the social cost of respiratory cancer cases attributable to occupational risk factors in France in 2010.

METHODS

According to the attributable fraction method and based on available epidemiological data from the literature, we estimated the number of respiratory cancer cases due to each identified risk factor. We used the cost-of-illness method with a prevalence-based approach. We took into account the direct and indirect costs. We estimated the cost of production losses due to morbidity (absenteeism and presenteeism) and mortality costs (years of production losses) in the market and nonmarket spheres.

RESULTS

The social cost of lung, larynx, sinonasal and mesothelioma cancer caused by exposure to asbestos, chromium, diesel engine exhaust, paint, crystalline silica, wood and leather dust in France in 2010 were estimated at between 917 and 2,181 million euros. Between 795 and 2,011 million euros (87-92%) of total costs were due to lung cancer alone. Asbestos was by far the risk factor representing the greatest cost to French society in 2010 at between 531 and 1,538 million euros (58-71%), ahead of diesel engine exhaust, representing an estimated social cost of between 233 and 336 million euros, and crystalline silica (119-229 million euros). Indirect costs represented about 66% of total costs.

CONCLUSION

Our assessment shows the magnitude of the economic impact of occupational respiratory cancers. It allows comparisons between countries and provides valuable information for policy-makers responsible for defining public health priorities.

Demonstration program of population-based lung cancer screening in China: Rationale and study design

BACKGROUND

Lung cancer is the leading cause of cancer-related death and has become an enormous economic burden in China. Low-dose spiral computed tomography (LDCT) screening could reduce lung cancer mortality. The feasibility of conducting a population-based lung cancer screening with LDCT in China is uncertain.

METHODS

In 2010, a demonstration program of lung cancer screening was initiated in China. High-risk individuals were enrolled in a cluster sampling design in different centers. Participants received baseline and annual screening with spiral CT and follow-up information was collected. The objective of this program is to evaluate the feasibility of conducting population-based LDCT lung cancer screening in the Chinese context. The rates of detection, early diagnosis and treatment are defined as indicators of program performance. The optimal management strategies for nodules are explored in the Chinese context based on experiences in other studies overseas.

RESULTS

A demonstration program of ongoing prospective, multi-center, population-based lung cancer screening is being performed in China.

CONCLUSIONS

This demonstration program will provide opportunities to explore the feasibility of LDCT lung cancer screening in the Chinese setting.

Whole adult organism transcriptional profiling of acute metal exposures in male zebrafish

Background

A convergence of technological breakthroughs in the past decade has facilitated the development of rapid screening tools for biomarkers of toxicant exposure and effect. Platforms using the whole adult organism to evaluate the genome-wide response to toxicants are especially attractive. Recent work demonstrates the feasibility of this approach in vertebrates using the experimentally robust zebrafish model. In the present study, we evaluated gene expression changes in whole adult male zebrafish following an acute 24 hr high dose exposure to three metals with known human health risks. Male adult zebrafish were exposed to nickel chloride, cobalt chloride or sodium dichromate concentrations corresponding to their respective 96 hr LC₂₀, LC₄₀ and LC₆₀. Histopathology was performed on a subset of metal-exposed zebrafish to phenotypically anchor transcriptional changes associated with each metal.

Results

Comparative analysis identified subsets of differentially expressed transcripts both overlapping and unique to each metal. Application of gene ontology (GO) and transcription factor (TF) enrichment algorithms revealed a number of key biological processes perturbed by metal poisonings and the master transcriptional regulators mediating gene expression changes. Metal poisoning differentially activated biological processes associated with ribosome biogenesis, proteosomal degradation, and p53 signaling cascades, while repressing oxygen-generating pathways associated with amino acid and lipid metabolism. Despite appreciable effects on gene regulation, nickel poisoning did not induce any morphological alterations in male zebrafish organs and tissues. Histopathological effects of cobalt remained confined to the olfactory system, while chromium targeted the gills, pharynx, and intestinal mucosa. A number of enriched transcription factors mediated the observed gene response to metal poisoning, including known targets such as p53, HIF1α, and the myc oncogene, and novel regulatory factors such as XBP1, GATA6 and HNF3β.

Conclusions

This work uses an experimentally innovative approach to capture global responses to metal poisoning and provides mechanistic insights into metal toxicity.

[Survey and analysis of awareness of lung cancer prevention and control in a LDCT lung cancer screening project in Tianjin Dagang Oilfield of China]

背景与目的

已有的研究表明提高人群对肺癌防治知识的认识水平，有助于肺癌高危人群肺癌筛查项目的参与度。本研究的目的是调查卫生部肺癌早诊早治大港项目点低剂量螺旋（low dose CT, LDCT）肺癌筛查人群肺癌防治知识知晓情况及个体因素对其的影响，为肺癌高发现场的综合防治提供依据。

方法

通过整群抽样和自愿参加方法对参加LDCT筛查的大港油田肺癌高发现场职工进行问卷调查。

结果

本次调查共获得有效问卷1, 633份，调查对象的平均年龄为60.08±6.58，男性1, 343人（82.2%），女性290（17.8%）。对肺癌的知晓率、危险因素、筛查方法，体检意愿以及治疗的知晓率分别为：64.5%、77.1%、43.7%、49.6%、52.8%。多因素Logistic回归分析结果表明：教育、年龄、吸烟包年、疾病史是调查对象肺癌防治知识知晓的影响因素，教育和年龄的OR值分别为0.567（95%CI: 0.439-0.733）和1.373（95%CI: 1.084-1.739）。调查人群中80.3%的人群能接受1年1次的体检，人群体检费用承受能力不高。对被调查者体检意愿进行多因素分析得出，性别、年龄、癌症知识知晓情况以及家庭年平均收入是筛查意愿的影响因素。

结论

教育程度和吸烟影响人群对肺癌防治知识的认知情况，应加强对低教育水平人群的癌症健康教育。在肺癌高发现场，肺癌的筛查应与戒烟和健康教育紧密结合，实行肺癌的综合防治。

[A cohort study on risk factors of lung cancer in Yunnan tin miners]

背景与目的

吸烟是肺癌的主要病因, 在矿工肺癌病因的研究中发现, 职业暴露因素也起重要作用。本研究旨在分析氡暴露、吸烟等危险因素对云锡矿工肺癌的影响, 为预防和控制肺癌高发提供科学依据。

方法

利用前瞻性队列研究方法, 对云锡矿工肺癌高危人群暴露因素对肺癌死亡的影响进行Cox多因素分析; 分析矿工肺癌危险与初始氡暴露年龄及氡暴露率的关系, 分析不同吸烟、氡暴露水平下肺癌死亡的危险, 并对吸烟和累积氡暴露量之间的交互作用进行分析。

结果

进入研究时的年龄、吸烟量、累积氡砷暴露、既往慢性支气管炎为云锡矿工肺癌的独立危险因素, 教育程度是矿工肺癌的保护性因素; 肺癌危险与氡暴露率间存在逆剂量率效应, 但与初始氡暴露年龄无明显关联; 吸烟和氡暴露对肺癌危险有显著的相加交互作用。

结论

云锡矿工肺癌高死亡率是多种因素共同作用的结果, 危险因素间的交互作用值得进一步深入研究。

Occupational exposures to aluminum and iron and risk of lung epithelium atypia in sudan

This study investigated the risk of lung cytological atypical changes in regards to occupational exposure to aluminum and iron. Detailed job histories were elicited from 130 incident cases with confirmed exposure to aluminum (50) or iron (80) and 157 population controls (nonexposed). Cytological atypia in sputum (dysplasia) was identified in four cases and none of controls (RR =10.8550; 95% CI = 0.5898 to 199.7815, P = 0.1086), hence, metaplasia was observed among 15 (11.5%) of the cases and 10 (6%) of controls (RR = 1.8115; 95% CI = 0.8424-3.8956; P = 0.1283). Evidences of viral infection were observed in 18 (14%) of the cases and 8 (5%) of controls (RR = 2.7173; 95% CI = 1.2213-6.0460; P = 0.0143). Moniliasis was observed in 28 (22%) of the cases and 19 (12%) of controls (RR = 1.6632; 95% CI = 0.9728-2.8435; P = 0.06). Cross-categorizations of aluminum exposure and iron use suggest greater risk associated with iron exposure than aluminum in these workers.

Variations of lung cancer risk from asbestos exposure: impact on estimation of population attributable fraction

The purpose of this study is to investigate the potential impact of differing lung cancer risks in study populations on estimating population attributable fraction (PAF) from asbestos exposure. Studies were identified via a MEDLINE search up to September 2009 and from the reference lists of publications about asbestos exposure and lung cancer risk. Relative risk estimates were extracted from 160 studies and meta-relative risks were calculated according to random-effect models. Hypothetical PAFs were calculated based on the meta results and on the difference exposure scenarios. The risks for lung cancer from asbestos exposure were variable according to the region as well as other study characteristics. The risk estimates proved higher in Asian countries (RR=3.53), in studies with 500 or fewer subjects (RR=2.26), and papers published in the 1990s or earlier (RR=1.91), than did those for European or North American countries, studies with more than 500 subjects, and papers published in the 2000s, respectively. The differences in PAFs between Asian and North American studies were 15.5%, 30.3%, and 36.2% when the exposure prevalence was 10%, 30%, and 50%, respectively. This study suggested that it is important to apply appropriate lung cancer estimates to each study population when calculating PAF from asbestos exposure.

Estimated burden of disease attributable to selected occupational exposures in the United Arab Emirates

BACKGROUND

As part of an effort to strengthen occupational safety and health programs, the United Arab Emirates (UAE) commissioned a study to estimate the burden of disease attributable to occupational exposure to carcinogens, particulate matter, and noise.

METHODS

We developed an innovative simulation model to estimate the occupational disease burden and facilitate future assessments as more field-based quantitative data become available.

RESULTS

We determined that, in 2008, an estimated 46 deaths (95% CI: 27-71) and 17,000 health-care facility visits (95% CI: 16,000-18,000), along with 4,500 cases of noise-induced hearing loss, were attributable to the occupational risk factors covered in this study. Lung cancer and leukemia were associated with the highest number of deaths (38), whereas asthma and chronic obstructive pulmonary disease contributed most to the health-care facility visits (nearly 16,900). The highest estimated occupational disease burden is in construction.

CONCLUSION

These results will help the UAE to institute new policies for environment, health, and safety management.

Lung cancer screening: a review of available data and current guidelines

Lung cancer is the leading cause of cancer mortality worldwide. A lack of clinical symptoms in early-stage disease frequently leads to diagnosis at a late stage, and a 15% 5-year survival rate in all patients so diagnosed. This has led to significant interest in effective screening methods to detect early-stage cancers, particularly for high-risk groups, such as current or former smokers. Early clinical trials focused on chest radiograph with or without sputum cytology and failed to show an improvement in mortality with screening. A meta-analysis also failed to show a difference in all-cause mortality. Subsequent protocols compared low-dose computed tomography (LDCT) scan with chest radiograph and documented increased detection of early-stage disease; however, they were not designed to prove a reduction in mortality. The most recent trials have focused on LDCT scans, including the National Lung Screening Trial. Data released from the National Lung Screening Trial demonstrated a statistically significant reduction in lung cancer deaths in patients screened with LDCT scans. When data from the study, including cost-effectiveness, are completely analyzed, they may lead to revision of current lung cancer screening recommendations to include LDCT scans in specific populations at high risk of developing lung cancer.

Investigation of occupational and environmental causes of respiratory cancers (ICARE): a multicenter, population-based case-control study in France

BACKGROUND

Occupational causes of respiratory cancers need to be further investigated: the role of occupational exposures in the aetiology of head and neck cancers remains largely unknown, and there are still substantial uncertainties for a number of suspected lung carcinogens. The main objective of the study is to examine occupational risk factors for lung and head and neck cancers.

METHODS/DESIGN

ICARE is a multi-center, population-based case-control study, which included a group of 2926 lung cancer cases, a group of 2415 head and neck cancer cases, and a common control group of 3555 subjects. Incident cases were identified in collaboration with cancer registries, in 10 geographical areas. The control group was a random sample of the population of these areas, with a distribution by sex and age comparable to that of the cases, and a distribution by socioeconomic status comparable to that of the population. Subjects were interviewed face to face, using a standardized questionnaire collecting particularly information on tobacco and alcohol consumption, residential history and a detailed description of occupational history. Biological samples were also collected from study subjects. The main occupational exposures of interest are asbestos, man-made mineral fibers, formaldehyde, polycyclic aromatic hydrocarbons, chromium and nickel compounds, arsenic, wood dust, textile dust, solvents, strong acids, cutting fluids, silica, diesel fumes, welding fumes. The complete list of exposures of interest includes more than 60 substances. Occupational exposure assessment will use several complementary methods: case-by-case evaluation of exposure by experts; development and use of algorithms to assess exposure from the questionnaires; application of job-exposure matrices.

DISCUSSION

The large number of subjects should allow to uncover exposures associated with moderate increase in risks, and to evaluate risks associated with infrequent or widely dispersed exposures. It will be possible to study joint effects of exposure to different occupational risk factors, to examine the interactions between occupational exposures, tobacco smoking, alcohol drinking, and genetic risk factors, and to estimate the proportion of respiratory cancers attributable to occupational exposures in France. In addition, information on many non-occupational risk factors is available, and the study will provide an excellent framework for numerous studies in various fields.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Exploring geographic variation in lung cancer incidence in Kentucky using a spatial scan statistic: elevated risk in the Appalachian coal-mining region

OBJECTIVES

We examined geographic patterns of lung cancer incidence in Kentucky. Recent research has suggested that the coal-mining industry contributes to lung cancer risk in Appalachia. We focused on the southeastern portion of the state, which has some of the highest lung cancer rates in the nation.

METHODS

We implemented a spatial scan statistic to identify areas with lung cancer incidence rates that were higher than expected, after adjusting for age, gender, and smoking. The Kentucky Cancer Registry supplied information on cases (1995-2007). The U.S. Census (2000) and several years of Behavioral Risk Factor Surveillance System data (1996-2006) provided county-level population and smoking data. We compared the results with coal-mining data from the Mining Safety and Health Administration and public water utility data from the Kentucky Division of Water.

RESULTS

We identified three clusters of counties with higher-than-expected rates. Cluster 1 (relative risk [RR] = 1.21, p<0.01) included 12 counties in southeastern Kentucky. Cluster 2 (RR=1.17, p<0.01) included three nearby counties in the same region. Several of the 15 counties in Cluster 3 (RR=1.04, p=0.01) were part of the Louisville, Kentucky, or Cincinnati, Ohio, metropolitan areas. All of the counties in Clusters 1 and 2 produced significant amounts of coal.

CONCLUSION

Environmental exposures related to the coal-mining industry could contribute to the high incidence of lung cancer in southeastern Kentucky. Lack of evidence for this effect in western Kentucky could be due to regional differences in mining practices and access to public water utilities. Future research should collect biological specimens and environmental samples to test for the presence of trace elements and other lung carcinogens.

Occupational lung cancer

Lung cancer is a multifactorial disease. Hereditary, genetic, and environmental factors interact in its genesis. The principal risk factor for lung cancer is smoking. However, the workplace provides an environment in which there is a risk of exposure to carcinogens. The International Agency for Research on Cancer currently lists 19 substances/work situations/occupations that have been proven to be associated with lung cancer (group 1). Thorough occupational history taking is not widely practiced in patients with lung cancer, which has a negative impact on the investigation of causality and, consequently, on the identification of cases of occupational cancer. The objectives of this review were to list the agents that are recognized as causes of lung cancer, to discuss the contribution of occupation to the development of the disease, to cite national studies on the subject, and to propose a list of procedures that are essential to the appropriate investigation of causality between lung cancer and occupation.

Crystalline silica and lung cancer: a critical review of the occupational epidemiology literature of exposure-response studies testing this hypothesis

IARC (2009; Metals, Particles and Fibres. IARC Monographs on the Evaluaton of Carcinogenic Risks to Humans. Volume 100C. Lyon, France: IARC) concluded that crystalline silica in occupational settings is a lung carcinogen. This conclusion is based primarily on studies with exposure-response (E-R) analyses and a pooled analysis of 10 major studies with about 1000 lung cancer cases. The purpose of this review is to critically assess this cancer classification based on E-R analyses in 18 studies from eight countries with about 2000 lung cancer cases and the same database used by IARC (2009) . The most appropriate exposure-response analysis is selected from latest study with least effect from bias, confounding, and presented graphically to assist individual assessment of the weight of evidence. Strength of association is consistently weak in the majority of studies. At the highest exposure level the mean relative risk (RR) is 1.5; four studies have strong associations (RRs > 2), three have moderate strong associations (RRs 1.5-2.0), six have weak-negligible associations (RRs 1-1.5), and five have no associations (RRs ≤1.0). Biological gradients were an inconsistent finding. Three studies had clear positive E-R trends; 3 had suggestive trends; and 12 had no E-R trends, 9 of which were flat or negative. There was a negative ER slope using RRs at the highest exposure of each study. Consistent findings of weak associations and lack of E-R trends does not support a causal association. Weight of evidence from occupational epidemiology does not support a causal association of lung cancer and silica exposure, which is contrary to the IARC conclusion using essentially the same data.

Prior lung disease and lung cancer risk in an occupational-based cohort in Yunnan, China

We used the data from a prospective cohort study among tin miners in Yunnan, China to investigate whether prior lung disease is a risk factor for lung cancer. Information on prior lung disease was obtained from baseline questionnaires. The Cox proportional hazards model was used to examine the relationship between prior lung disease and lung cancer risk. From 1992 to 2001, a total of 502 lung cancer cases were confirmed among 9295 cohort participants. Prior chronic bronchitis was associated with an increase in lung cancer risk with an adjusted HR of 1.50 (95% CI: 1.24-1.81). There was an increased risk of developing squamous cell carcinoma in the setting of prior chronic bronchitis and small cell carcinoma in association with asthma with an adjusted HRs of 1.57 (95% CI: 1.19-2.09) and 2.56 (95% CI: 1.38-4.75), respectively. This prospective study provides further evidence that prior chronic bronchitis correlates with increased lung cancer risk, especially for squamous cell carcinoma. Asthma is associated with increased risk of small cell lung carcinoma.

Occupational lung cancer in US women, 1984-1998

BACKGROUND

Lung cancer is the leading cause of cancer death in US women, accounting for 72,130 deaths in 2006. In addition to smoking cessation, further reduction of the burden of lung cancer mortality can be made by preventing exposure to occupational lung carcinogens. Data for occupational exposures and health outcomes of US working women are limited.

METHODS

Population-based mortality data for 4,570,711 women who died between 1984 and 1998 in 27 US States were used to evaluate lung cancer proportionate mortality over time by the usual occupation and industry reported on death certificates. Lung cancer proportionate mortality ratios were adjusted for smoking, using data from the National Health Interview Survey (NHIS) and the American Cancer Society's Cancer Prevention Study II.

RESULTS

Analyses revealed that 194,382 white, 18,225 Black and 1,515 Hispanic women died 1984-1998 with lung cancer reported as the underlying cause of death. Following adjustment for smoking, significant excess proportionate lung cancer mortality was observed among US women working in the US manufacturing; transportation; retail trade; agriculture, forestry, and fishing; and nursing/personal care industries. Women employed in precision production, technical, managerial, professional specialty, and administrative occupations experienced some of the highest significantly excess proportionate lung cancer mortality during 1984-1998.

CONCLUSIONS

The results of our study point to significantly elevated risks for lung cancer after adjustment for smoking among women in several occupations and industries. Because 6-17% of lung cancer in US males is attributable to known exposures to occupational carcinogens, and since synergistic interactions between cigarette smoke and other occupational lung carcinogens have been noted, it is important to continue research into the effects of occupational exposures on working men and women.

Knowns and unknowns on burden of disease due to chemicals: a systematic review

BACKGROUND

Continuous exposure to many chemicals, including through air, water, food, or other media and products results in health impacts which have been well assessed, however little is known about the total disease burden related to chemicals. This is important to know for overall policy actions and priorities. In this article the known burden related to selected chemicals or their mixtures, main data gaps, and the link to public health policy are reviewed.

METHODS

A systematic review of the literature for global burden of disease estimates from chemicals was conducted. Global disease due to chemicals was estimated using standard methodology of the Global Burden of Disease.

RESULTS

In total, 4.9 million deaths (8.3% of total) and 86 million Disability-Adjusted Life Years (DALYs) (5.7% of total) were attributable to environmental exposure and management of selected chemicals in 2004. The largest contributors include indoor smoke from solid fuel use, outdoor air pollution and second-hand smoke, with 2.0, 1.2 and 0.6 million deaths annually. These are followed by occupational particulates, chemicals involved in acute poisonings, and pesticides involved in self-poisonings, with 375,000, 240,000 and 186,000 annual deaths, respectively.

CONCLUSIONS

The known burden due to chemicals is considerable. This information supports decision-making in programmes having a role to play in reducing human exposure to toxic chemicals. These figures present only a number of chemicals for which data are available, therefore, they are more likely an underestimate of the actual burden. Chemicals with known health effects, such as dioxins, cadmium, mercury or chronic exposure to pesticides could not be included in this article due to incomplete data and information. Effective public health interventions are known to manage chemicals and limit their public health impacts and should be implemented at national and international levels.

Occupational lung cancer surveillance in South Korea, 2006-2009

Objectives

The lung cancer mortality in Korea has increased remarkably during the last 20 years, and has been the first leading cause of cancer-related deaths since 2000. The aim of the current study was to examine the time trends of occupational lung cancer and carcinogens exposure during the period 2006-2009 in South Korea, by assessing the proportion of occupational burden.

Methods

We defined occupational lung cancer for surveillance, and developed a reporting protocol and reporting website for the surveillance of occupational lung cancer. The study patients were chosen from 9 participating university hospitals in the following 7 areas: Seoul, Incheon, Wonju, Daejeon, Daegu, Busan, and Gwangju.

Results

The combined proportion of definite and probable occupational lung cancer among all lung cancers investigated in this study was 10.0%, 8.6%, 10.7%, and 15.8% in the years 2006 to 2009, respectively, with an average of 11.7% over the four-year study period. The main carcinogens were asbestos, crystalline silica, radon, polyaromatic hydrocarbons (PAHs), diesel exhaust particles, chromium, and nickel.

Conclusion

We estimated that about 11.7% of the incident lung cancer was preventable. This reveals the potential to considerably reduce lung cancer by intervention in occupational fields.

Antioxidant therapy attenuates oxidative stress in the blood of subjects exposed to occupational airborne contamination from coal mining extraction and incineration of hospital residues

Coal mining and incineration of solid residues of health services (SRHS) generate several contaminants that are delivered into the environment, such as heavy metals and dioxins. These xenobiotics can lead to oxidative stress overgeneration in organisms and cause different kinds of pathologies, including cancer. In the present study the concentrations of heavy metals such as lead, copper, iron, manganese and zinc in the urine, as well as several enzymatic and non-enzymatic biomarkers of oxidative stress in the blood (contents of lipoperoxidation = TBARS, protein carbonyls = PC, protein thiols = PT, α-tocopherol = AT, reduced glutathione = GSH, and the activities of glutathione S-transferase = GST, glutathione reductase = GR, glutathione peroxidase = GPx, catalase = CAT and superoxide dismutase = SOD), in the blood of six different groups (n = 20 each) of subjects exposed to airborne contamination related to coal mining as well as incineration of solid residues of health services (SRHS) after vitamin E (800 mg/day) and vitamin C (500 mg/day) supplementation during 6 months, which were compared to the situation before the antioxidant intervention (Ávila et al., Ecotoxicology 18:1150-1157, 2009; Possamai et al., Ecotoxicology 18:1158-1164, 2009). Except for the decreased manganese contents, heavy metal concentrations were elevated in all groups exposed to both sources of airborne contamination when compared to controls. TBARS and PC concentrations, which were elevated before the antioxidant intervention decreased after the antioxidant supplementation. Similarly, the contents of PC, AT and GSH, which were decreased before the antioxidant intervention, reached values near those found in controls, GPx activity was reestablished in underground miners, and SOD, CAT and GST activities were reestablished in all groups. The results showed that the oxidative stress condition detected previously to the antioxidant supplementation in both directly and indirectly subjects exposed to the airborne contamination from coal dusts and SRHS incineration, was attenuated after the antioxidant intervention.

Assessing environmental and occupational risk factors for lung cancer in Mexican-Americans

BACKGROUND

We investigated environmental and occupational exposures and smoking history (while controlling for demographics) in a population of Mexican-American lung cancer cases and controls from the Houston metropolitan area.

METHODS

Data were collected between 1991 and 2005 as part of an on-going multi-racial/ethnic, lung cancer case-control study. Cases included 212 Mexican-American lung cancer cases from UT MD Anderson Cancer Center. Controls (n = 328) were recruited from Houston's largest multispecialty group practice and frequency matched to the cases by age (± 5 years), sex, and ethnicity. Environmental and occupational factors were analyzed and odds ratios and 95% confidence intervals were calculated using logistic regression.

RESULTS

We detected elevated risks of lung cancer associated with pesticide exposure and found conventional and antimicrobial (e.g., sterilizers, disinfectants, antiseptics) pesticides were associated with an increased risk of lung cancer in Mexican-Americans (conventional pesticides and antimicrobial pesticides combined: OR = 1.80, 95% CI 1.13-2.86; conventional pesticides: OR = 2.05, 95% CI 1.23-2.39; antimicrobial pesticides: OR = 2.48, 95% CI 1.46-4.21).

CONCLUSIONS

Although we found over a two-fold increased risk of lung cancer among Mexican-Americans for pesticides, we could not identify individual pesticides. Our findings are an important preliminary step in identifying factors that are specifically associated with lung cancer risk among Mexican Americans.

Analysis of multiple exposures: an empirical comparison of results from conventional and semi-bayes modeling strategies

BACKGROUND

Analysts of epidemiologic data often contend with the problem of estimating the independent effects of many correlated exposures. General approaches include assessing each exposure separately, adjusting for some subset of other exposures, or assessing all exposures simultaneously in a single model such as semi-Bayes modeling. The optimal strategy remains uncertain, and it is unclear to what extent different reasonable approaches influence findings. We provide an empirical comparison of results from several modeling strategies.

METHODS

In an occupational case-control study of lung cancer with 184 exposure substances, we implemented 6 modeling strategies to estimate odds ratios for each exposure-cancer association. These included one-exposure-at-a-time models with various confounder selection criteria (such as a priori selection or a change-in-the-estimate criterion) and semi-Bayes models, one version of which integrated information on previous evidence and chemical properties.

RESULTS

While distributions of odds ratios were broadly similar across the 6 analytic strategies, there were some differences in point estimates and in substances manifesting statistically significant odds ratios, particularly between strategies with few or no occupational covariates and those with many. Semi-Bayes models produced fewer statistically significant odds ratios than other methods. A simple semi-Bayes model that shrank all the 184 estimates to a common mean yielded nearly identical results to one that integrated considerable prior information.

CONCLUSION

Different modeling strategies can lead to different results. Considering the conceptual and pragmatic difficulties of identifying confounders, these results suggest that it would be unwise to place uncritical reliance on any single strategy.

Lung cancer and occupation in a population-based case-control study

The authors examined the relation between occupation and lung cancer in the large, population-based Environment And Genetics in Lung cancer Etiology (EAGLE) case-control study. In 2002-2005 in the Lombardy region of northern Italy, 2,100 incident lung cancer cases and 2,120 randomly selected population controls were enrolled. Lifetime occupational histories (industry and job title) were coded by using standard international classifications and were translated into occupations known (list A) or suspected (list B) to be associated with lung cancer. Smoking-adjusted odds ratios and 95% confidence intervals were calculated with logistic regression. For men, an increased risk was found for list A (177 exposed cases and 100 controls; odds ratio = 1.74, 95% confidence interval: 1.27, 2.38) and most occupations therein. No overall excess was found for list B with the exception of filling station attendants and bus and truck drivers (men) and launderers and dry cleaners (women). The authors estimated that 4.9% (95% confidence interval: 2.0, 7.8) of lung cancers in men were attributable to occupation. Among those in other occupations, risk excesses were found for metal workers, barbers and hairdressers, and other motor vehicle drivers. These results indicate that past exposure to occupational carcinogens remains an important determinant of lung cancer occurrence.

Tobacco, Genetic Susceptibility and Lung cancer

Exposure to tobacco smoke is an established risk factor for lung cancer, although a possible role for genetic susceptibility in the development of lung cancer has been inferred from familial clustering of the disease and segregation analysis. Findings of familial aggregation and statistical evidence for a major susceptibility gene have led to the search for high penetrant, rare, single genes and low penetrant, high frequency susceptibility genes for lung cancer. The relatively small number of linkage studies conducted to date, have identified potential lung cancer susceptibility loci on chromosomes 6q, 12p, and 19q. A variety of studies have examined single nucleotide polymorphisms of several low penetrant, high frequency genes encoding for enzymes involved in the metabolism of carcinogens and DNA damage repair, as likely candidate susceptibility genes. These studies have produced somewhat conflicting findings and, when significant, only modest associations have been reported. Relatively few studies have looked for potential gene-environment interactions, explored associations between two or more genetic polymorphisms or evaluated interactions between genetic polymorphisms and endogenous risk factors. Few large scale genome wide association studies conducted recently have provided evidence that common variation on chromosome 15q25.1, 5p15.33 and 6p21.33 influences lung cancer risk and cancer types with strong environmental risk factors. It is hoped that newer research strategies, selecting candidate genes within pathways and genotype at multiple markers within a gene, employing new technologies, may allow complete coverage of the variation within candidate genes in multiple pathways and to unravel the genetic susceptibility to lung cancer. This knowledge could, in turn, be used to identify persons at risk, to individualize treatments such as chemoprevention, to personalize harms of smoking and to motivate cessation.

Occupational airborne contamination in south Brazil: 1. Oxidative stress detected in the blood of coal miners

Reactive oxygen species and nitrogen species have been implicated in the pathogenesis of coal dust-induced toxicity. The present study investigated several oxidative stress biomarkers (Contents of lipoperoxidation = TBARS, reduced = GSH, oxidized = GSSG and total glutathione = TG, alpha-tocopherol, and the activities of glutathione S-transferase = GST, glutathione reductase = GR, glutathione peroxidase = GPx, catalase = CAT and superoxide dismutase = SOD), in the blood of three different groups (n = 20 each) exposed to airborne contamination associated with coal mining activities: underground workers directly exposed, surface workers indirectly exposed, residents indirectly exposed (subjects living near the mines), and controls (non-exposed subjects). Plasma TBARS were increased and whole blood TG and GSH levels were decreased in all groups compared to controls. Plasma alpha-tocopherol contents showed approximately half the values in underground workers compared to controls. GST activity was induced in workers and also in residents at the vicinity of the mining plant, whilst CAT activity was induced only in mine workers. SOD activity was decreased in all groups examined, while GPx activity showed decreased values only in underground miners, and GR did not show any differences among the groups. The results showed that subjects directly and indirectly exposed to coal dusts face an oxidative stress condition. They also indicate that people living in the vicinity of the mine plant are in health risk regarding coal mining-related diseases.

Estimating the incidence of lung cancer attributable to occupational exposure in Iran

OBJECTIVE

The aim of this study was to estimate the fraction of lung cancer incidence in Iran attributed to occupational exposures to the well-established lung cancer carcinogens, including silica, cadmium, nickel, arsenic, chromium, diesel fumes, beryllium, and asbestos.

METHODS

Nationwide exposure to each of the mentioned carcinogens was estimated using workforce data from the Iranian population census of 1995, available from the International Labor Organization (ILO) website. The prevalence of exposure to carcinogens in each industry was estimated using exposure data from the CAREX (CARcinogen EXposure) database, an international occupational carcinogen information system kept and maintained by the European Union. The magnitude of the relative risk of lung cancer for each carcinogen was estimated from local and international literature. Using the Levin modified population attributable risk (incidence) fraction, lung cancer incidence (as estimated by the Tehran Population-Based Cancer Registry) attributable to workplace exposure to carcinogens was estimated.

RESULTS

The total workforce in Iran according to the 1995 census identified 12,488,020 men and 677,469 women. Agriculture is the largest sector with 25% of the male and 0.27% of female workforce. After applying the CAREX exposure estimate to each sector, the proportion exposed to lung carcinogens was 0.08% for male workers and 0.02% for female workers. Estimating a relative risk of 1.9 (95% CI of 1.7-2.1) for high exposure and 1.3 (95% CI 1.2-1.4) for low exposure, and employing the Levin modified formula, the fraction of lung cancer attributed to carcinogens in the workplace was 1.5% (95% CI of 1.2-1.9) for females and 12% (95% CI of 10-15) for males. These fractions correspond to an estimated incidence of 1.3 and 0.08 cases of lung cancer per 100,000 population for males and females, respectively.

CONCLUSION

The incidence of lung cancer due to occupational exposure is low in Iran and, as in other countries, more lung cancer is due to occupational exposure among males than females.

The burden of exposure-related diffuse lung disease

Estimating the burden of exposure-related diffuse lung disease in terms of health effects and economic burden remains challenging. Labor statistics are inadequate to define the scope of the problem, and few studies have analyzed the prevalence of exposure-related illnesses and the subsequent health care cost. Well-defined exposures, such as those associated with coal mines, asbestos mines, and stonecutting, have led to more accurate assessment of prevalence and cost. As governmental regulation of workplace exposure has increased, the prevalence of diseases such as silicosis and coal workers' pneumoconiosis has diminished. However, the health and economic effects of diseases with long latency periods, such as asbestosis and mesothelioma, continue to increase in the short term. Newer exposures, such as those related to air pollution, nylon flock, and the World Trade Center collapse, have added to these costs. As a result, estimates of cost for occupational diseases, including respiratory illnesses, exceed $26 billion annually, and the true economic burden is likely much higher.