Occupation and histopathology of lung cancer: A case-control study in Rosario, Argentina

Dose-response-relationship between occupational exposure to diesel engine emissions and lung cancer risk: A systematic review and meta-analysis

BACKGROUND

In 2012, the International Agency for Research on Cancer (IARC) concluded that diesel engine emissions (DEE) emissions cause cancer in humans. However, there is still controversy surrounding this conclusion, due to several studies since the IARC decision citing a lack of evidence of a dose-response relationship.

OBJECTIVES

Through a systematic review, we aimed to evaluate all evidence on the association between occupational DEE and lung cancer to investigate whether there is an increased risk of lung cancer for workers exposed to DEE and if so, to describe the dose-response relationship.

METHODS

We registered the review protocol with PROSPERO and searched for observational studies in relevant literature databases. Two independent reviewers screened the studies' titles/abstracts and full texts, and extracted and assessed their quality. Studies with no direct DEE measurement but with information on length of exposure for high-risk occupations were assigned exposure values based on the DEE Job-Exposure-Matrix (DEE-JEM). After assessing quality and informativeness, we selected appropriate studies for the dose-response meta-analysis.

RESULTS

Sixty-five reports (from thirty-seven studies) were included in the review; one had a low risk of bias (RoB) (RR per 10 μg/m3-years: 1.014 [95%CI 1.007-1.021]). There was an increased, statistically significant risk of lung cancer with increasing DEE exposure for all studies (RR per 10 μg/m3-years = 1.013 [95%CI 1.004-1.021]) as well as for studies with a low RoB in the exposure category (RR per 10 μg/m3-years = 1.008 [95% CI1.001-1.015]). We obtained a doubling dose of 555 μg/m3-years for all studies and 880 μg/m3-years for studies with high quality in the exposure assessment.

DISCUSSION

We found a linear positive dose-response relationship for studies with high quality in the exposure domain, even though all studies had an overall high risk of bias. Current threshold levels for DEE exposure at the workplace should be reconsidered.

Risk of lung cancer among welders and flame cutters: A systematic review and meta-analysis of case controlled studies

OBJECTIVES

The process of flame-cutting and welding is believed to be highly hazardous for workers involved in related industries. The study aims to provide a comprehensive quantitative effect of the risk of lung cancer due to exposure to welding fumes.

METHODS

A systematic review was conducted to extract published estimates of Odd's Ratio (OR) of the association of lung cancer and exposure to welding fumes, till 2022. Studies were extracted from the PubMed and Cochrane database and Google Scholar. Studies from all parts of the world were considered. Through a meta-analysis conducted with random effects model, a forest plot was created, and publication bias was checked using a funnel plot.

RESULTS

The meta-analysis yielded an OR of 1.28 (95% CI 1.055-1.55), with a moderately high heterogeneity between the studies [I2=72%; T2=0.0524;Q=36.12(P<0.001)]. The sensitivity and influence analysis confirmed the absence of highly influential studies that may have led to potentially distorted outcomes. The funnel plot showed no evidence of publication bias among the studies included in this analysis.

CONCLUSION

As the association between lung cancer and occupational hazards from exposure to welding fumes is certain, there is a need to control and regulate industrial activities that involve welding and flame cutting. Already, restrictions on safe levels of fume in the workplace are in operation.

The effect of occupational exposure to welding fumes on trachea, bronchus and lung cancer: A systematic review and meta-analysis from the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury

BACKGROUND

The World Health Organization (WHO) and the International Labour Organization (ILO) are the producers of the WHO/ILO Joint Estimates of the Work-related Burden of Disease and Injury (WHO/ILO Joint Estimates). Welding fumes have been classified as carcinogenic to humans (Group 1) by the WHO International Agency for Research on Cancer (IARC) in IARC Monograph 118; this assessment found sufficient evidence from studies in humans that welding fumes are a cause of lung cancer. In this article, we present a systematic review and meta-analysis of parameters for estimating the number of deaths and disability-adjusted life years from trachea, bronchus, and lung cancer attributable to occupational exposure to welding fumes, to inform the development of WHO/ILO Joint Estimates on this burden of disease (if considered feasible).

OBJECTIVES

We aimed to systematically review and meta-analyse estimates of the effect of any (or high) occupational exposure to welding fumes, compared with no (or low) occupational exposure to welding fumes, on trachea, bronchus, and lung cancer (three outcomes: prevalence, incidence, and mortality).

DATA SOURCES

We developed and published a protocol, applying the Navigation Guide as an organizing systematic review framework where feasible. We searched electronic databases for potentially relevant records from published and unpublished studies, including Medline, EMBASE, Web of Science, CENTRAL and CISDOC. We also searched grey literature databases, Internet search engines, and organizational websites; hand-searched reference lists of previous systematic reviews; and consulted additional experts.

STUDY ELIGIBILITY AND CRITERIA

We included working-age (≥15 years) workers in the formal and informal economy in any Member State of WHO and/or ILO but excluded children (<15 years) and unpaid domestic workers. We included randomized controlled trials, cohort studies, case-control studies, and other non-randomized intervention studies with an estimate of the effect of any (or high) occupational exposure to welding fumes, compared with occupational exposure to no (or low) welding fumes, on trachea, bronchus, and lung cancer (prevalence, incidence, and mortality).

STUDY APPRAISAL AND SYNTHESIS METHODS

At least two review authors independently screened titles and abstracts against the eligibility criteria at a first review stage and full texts of potentially eligible records at a second stage, followed by extraction of data from qualifying studies. If studies reported odds ratios, these were converted to risk ratios (RRs). We combined all RRs using random-effects meta-analysis. Two or more review authors assessed the risk of bias, quality of evidence, and strength of evidence, using the Navigation Guide tools and approaches adapted to this project. Subgroup (e.g., by WHO region and sex) and sensitivity analyses (e.g., studies judged to be of "high"/"probably high" risk of bias compared with "low"/"probably low" risk of bias) were conducted.

RESULTS

Forty-one records from 40 studies (29 case control studies and 11 cohort studies) met the inclusion criteria, comprising over 1,265,512 participants (≥22,761 females) in 21 countries in three WHO regions (Region of the Americas, European Region, and Western Pacific Region). The exposure and outcome were generally assessed by job title or self-report, and medical or administrative records, respectively. Across included studies, risk of bias was overall generally probably low/low, with risk judged high or probably high for several studies in the domains for misclassification bias and confounding. Our search identified no evidence on the outcome of having trachea, bronchus, and lung cancer (prevalence). Compared with no (or low) occupational exposure to welding fumes, any (or high) occupational exposure to welding fumes increased the risk of acquiring trachea, bronchus, and lung cancer (incidence) by an estimated 48 % (RR 1.48, 95 % confidence interval [CI] 1.29-1.70, 23 studies, 57,931 participants, I² 24 %; moderate quality of evidence). Compared with no (or low) occupational exposure to welding fumes, any (or high) occupational exposure to welding fumes increased the risk dying from trachea, bronchus, and lung cancer (mortality) by an estimated 27 % (RR 1.27, 95 % CI 1.04-1.56, 3 studies, 8,686 participants, I² 0 %; low quality of evidence). Our subgroup analyses found no evidence for difference by WHO region and sex. Sensitivity analyses supported the main analyses.

CONCLUSIONS

Overall, for incidence and mortality of trachea, bronchus, and lung cancer, we judged the existing body of evidence for human data as "sufficient evidence of harmfulness" and "limited evidence of harmfulness", respectively. Occupational exposure to welding fumes increased the risk of acquiring and dying from trachea, bronchus, and lung cancer. Producing estimates for the burden of trachea, bronchus, and lung cancer attributable to any (or high) occupational exposure to welding fumes appears evidence-based, and the pooled effect estimates presented in this systematic review could be used as input data for the WHO/ILO Joint Estimates. PROTOCOL IDENTIFIER: https://doi.org/10.1016/j.envint.2020.106089.

[Primary lung cancer and occupational exposure in a North African population]

Les cancers broncho-pulmonaires (CBP) sont parmi les cancers les plus fréquents, de pronostic redoutable, l´origine professionnelle est fréquente, mais souvent sous-estimés. L'objectif était d´évaluer la proportion des Cancers Broncho-pulmonaires (CBP) présumés d´origine professionnelle et de rechercher la relation entre la nature de l´exposition et le type histologique du CBP. Cette étude épidémiologique rétrospective, a été réalisée au service de pneumologie de l´Etablissement Public Hospitalier (EPH) de Rouïba. Entre janvier 2014 et juin 2019, nous avons colligé 357 cas atteints de CBP avec preuve histologique. Le recueil des histoires médicales et professionnelles fut effectué. Les matrices emploi-exposition ont été utilisées pour le repérage des différentes expositions professionnelles. La population d´étude comprenait 357 patients dont la moyenne d´âge était de 63,9±11,1 ans et un sex-ratio de 7,4 hommes pour une femme. Il y avait 76,5% des sujets qui fumaient ou avaient fumé en moyenne 42 P/A. Le type histologique était dans 88,8% un carcinome bronchique non à petite cellule. L'ensemble des professions étudiées seraient responsables de 50,7% des cancers bronchiques primitifs, dont 26,5% pour les professions de chauffeurs poids lourds et conducteurs d´engins. L´imputabilité des cancers broncho-pulmonaires (CBP) à l´origine professionnelle est loin d´être négligeable mais souvent méconnue; du fait du caractère multifactoriel et du temps de latence entre l´exposition et l´apparition de la maladie, avec un impact sur le type histologique du cancer broncho-pulmonaire.

Welding fumes and lung cancer: a meta-analysis of case-control and cohort studies

BACKGROUND

An estimated 110 million workers are exposed to welding fumes worldwide. Welding fumes are classified by the International Agency for Research on Cancer as carcinogenic to humans (group 1), based on sufficient evidence of lung cancer from epidemiological studies.

OBJECTIVE

To conduct a meta-analysis of case-control and cohort studies on welding or exposure to welding fumes and risk of lung cancer, accounting for confounding by exposure to asbestos and tobacco smoking.

METHODS

The literature was searched comprehensively in PubMed, reference lists of relevant publications and additional databases. Overlapping populations were removed. Meta-relative risks (mRRs) were calculated using random effects models. Publication bias was assessed using funnel plot, Eggers's test and Begg's test.

RESULTS

Forty-five studies met the inclusion criteria (20 case-control, 25 cohort/nested case-control), which reduced to 37 when overlapping study populations were removed. For 'ever' compared with 'never' being a welder or exposed to welding fumes, mRRs and 95% CIs were 1.29 (1.20 to 1.39; I2=26.4%; 22 studies) for cohort studies, 1.87 (1.53 to 2.29; I2=44.1%; 15 studies) for case-control studies and 1.17 (1.04 to 1.38; I2=41.2%) for 8 case-control studies that adjusted for smoking and asbestos exposure. The mRRs were 1.32 (95% CI 1.20 to 1.45; I2=6.3%; 15 studies) among 'shipyard welders', 1.44 (95% CI 1.07 to 1.95; I2=35.8%; 3 studies) for 'mild steel welders' and 1.38 (95% CI 0.89 to 2.13; I2=68.1%; 5 studies) among 'stainless steel welders'. Increased risks persisted regardless of time period, geographic location, study design, occupational setting, exposure assessment method and histological subtype.

CONCLUSIONS

These results support the conclusion that exposure to welding fumes increases the risk of lung cancer, regardless of the type of steel welded, the welding method (arc vs gas welding) and independent of exposure to asbestos or tobacco smoking.

Lung cancer risk and occupational exposures in crop farming: results from the AGRIculture and CANcer (AGRICAN) cohort

Objectives

Farmers are considered at lower risk of lung cancer. However, specific tasks can expose them to hazardous air contaminants such as pesticides, diesel exhaust and mineral dust. This study aimed to assess the associations between various crops and related tasks and the risk of lung cancer, overall and by histological subtypes.

Methods

AGRIculture and CANcer is a prospective French cohort of individuals affiliated to the agricultural health insurance scheme. Incident lung cancers (n=897) were identified by cancer registries from enrolment (2005–2007) to 2013. Data on crop and livestock exposure during lifetime were obtained from the enrolment questionnaire. We used a Cox model with attained age as timescale, adjusted for gender, smoking history and exposure to cattle and horses. Effects of duration and surface were assessed and analyses stratified on gender and smoking status were performed.

Results

Winegrowers were at higher risk of adenocarcinoma (HR=1.27 (95% CI 0.94 to 1.72)). We also found an association between pea growing and small cell lung cancer: significant effect of duration (ptrend=0.04) and the suggestion of a surface–effect relationship (ptrend=0.06); increased risk (HR=2.38 (95% CI 1.07 to 5.28)) for pesticide users; and significant effect of duration (ptrend=0.01) for harvesters. The risk of squamous cell carcinoma was increased for sunflower growing (HR=1.59 (95% CI 0.97 to 2.62), fruit-tree pruning (HR=1.44 (95% CI 0.92 to 2.27)) and pesticide use on beets (HR=1.47 (95% CI 0.92 to 2.34)). Corn and/or wheat/barley growers were at lower risk of lung cancer.

Conclusions

Our results suggest associations between lung cancer and several crop-related tasks, even if we cannot rule out some chance findings due to multiple comparisons.

Cancer Risks among Welders and Occasional Welders in a National Population-Based Cohort Study: Canadian Census Health and Environmental Cohort

BACKGROUND

Welders are exposed to many known and suspected carcinogens. An excess lung cancer risk among welders is well established, but whether this is attributable to welding fumes is unclear. Excess risks of other cancers have been suggested, but not established. We investigated welding cancer risks in the population-based Canadian Census Health and Environmental Cohort.

METHODS

Among 1.1 million male workers, 12,845 welders were identified using Standard Occupational Classification codes and followed through retrospective linkage of 1991 Canadian Long Form Census and Canadian Cancer Registry (1992-2010) records. Hazard ratios (HRs) were calculated using Cox proportional hazards models based on estimated risks of lung cancer, mesothelioma, and nasal, brain, stomach, kidney, and bladder cancers, and ocular melanoma. Lung cancer histological subtypes and risks by industry group and for occasional welders were examined. Some analyses restricted comparisons to blue-collar workers to minimize effects of potential confounders.

RESULTS

Among welders, elevated risks were observed for lung cancer [HR: 1.16, 95% confidence interval (CI): 1.03-1.31], mesothelioma (HR: 1.78, 95% CI: 1.01-3.18), bladder cancer (HR: 1.40, 95% CI: 1.15-1.70), and kidney cancer (HR: 1.30, 95% CI: 1.01-1.67). When restricted to blue-collar workers, lung cancer and mesothelioma risks were attenuated, while bladder and kidney cancer risks increased.

CONCLUSION

Excess risks of lung cancer and mesothelioma may be partly attributable to factors including smoking and asbestos. Welding-specific exposures may increase bladder and kidney cancer risks, and particular sources of exposure should be investigated. Studies that are able to disentangle welding effects from smoking and asbestos exposure are needed.

Occupational exposure to endotoxins and lung cancer risk: results of the ICARE Study

Objectives

To investigate the role of occupational exposure to endotoxins in lung cancer in a French population-based case–control study (ICARE (Investigation of occupational and environmental causes of respiratory cancers)).

Methods

Detailed information was collected on the occupational history and smoking habits from 2926 patients with histologically confirmed lung cancer and 3555 matched controls. We evaluated each subject’s endotoxin exposure after cross referencing International Standard Classification of Occupations (ISCO) codes (for job tasks) and Nomenclature d'Activités Françaises (NAF) codes (for activity sectors). Endotoxin exposure levels were attributed to each work environment based on literature reports. ORs and 95% CIs were estimated using unconditional logistic regression models and controlled for main confounding factors.

Results

An inverse association between exposure to endotoxins and lung cancer was found (OR=0.80, 95% CI 0.66 to 0.95). Negative trends were shown with duration and cumulative exposure, and the risk was decreased decades after exposure cessation (all statistically significant). Lung cancer risk was particularly reduced among workers highly exposed (eg, in dairy, cattle, poultry, pig farms), but also in those weakly exposed (eg, in waste treatment). Statistically significant interactions were shown with smoking, and never/light smokers were more sensitive to an endotoxin effect than heavy smokers (eg, OR=0.14, 95% CI 0.06 to 0.32 and OR=0.80, 95% CI 0.45 to 1.40, respectively, for the quartiles with the highest cumulative exposure, compared with those never exposed). Pronounced inverse associations were shown with adenocarcinoma histological subtype (OR=0.37, 95% CI 0.25 to 0.55 in the highly exposed).

Conclusions

Our findings suggest that exposure to endotoxins, even at a low level, reduces the risk of lung cancer.

Lung cancer risk among workers in the construction industry: results from two case-control studies in Montreal

BACKGROUND

Given the large number of workers in the construction industry, it is important to derive accurate and valid estimates of cancer risk, and in particular lung cancer risk. In most previous studies, risks among construction workers were compared with general populations including blue and white collar workers. The main objectives of this study were to assess whether construction workers experience excess lung cancer risk, and whether exposure to selected construction industry exposures carries excess risks. We wished to address these objectives within the sub-population of blue collar workers.

METHODS

Two case-control studies were conducted in Montreal. Combined, they included 1593 lung cancer cases and 1427 controls, of whom 1304 cases and 1081 controls had been blue collar workers. Detailed lifetime job histories were obtained and translated by experts into histories of exposure to chemical agents. The two key analyses were to estimate odds ratio (OR) estimates of lung cancer risk: a) for all blue-collar construction workers compared with other blue-collar workers, and b) for construction workers exposed to each of 20 exposure agents found in the construction industry compared with construction workers unexposed to those agents. All analyses were conducted using unconditional logistic regression adjusted for socio-demographic factors and smoking history.

RESULTS

The OR for all construction workers combined was 1.11 (95 % CI: 0.90-1.38), based on 381 blue collar construction workers. Analyses of specific exposures were hampered by small numbers and imprecise estimates. While none of 20 occupational agents examined was significantly associated with lung cancer, the following agents manifested non-significantly elevated ORs: asbestos, silica, Portland cement, soil dust, calcium oxide and calcium sulfate.

CONCLUSIONS

Compared with other blue collar workers, there was only a slight increased risk of lung cancer for subjects who ever held an occupation in the construction industry. The analyses of agents within the construction industry produced imprecise estimates of risk, but nevertheless pointed to some plausible associations. Excess risks for asbestos and silica were in line with previous knowledge. The possible excess risks with the other inorganic dusts require further corroboration.

Using the Negative Exponential Model to Describe Changes in Risk of Smoking-Related Diseases following Changes in Exposure to Tobacco

Recently published analyses for four smoking-related diseases show that the declining excess relative risk by time quit is well fitted by the negative exponential model. These analyses estimated the half-life of this excess, that is, the time after quitting when the excess relative risk reaches half that for continuing smokers. We describe extensions of the simple model. One quantifies the decline following an exposure reduction. We show that this extension satisfactorily predicts results from studies investigating the effect of reducing cigarette consumption. It may also be relevant to exposure reductions following product-switching. Another extension predicts changes in excess relative risk occurring following multiple exposure changes over time. Suitable published epidemiological data are unavailable to test this, and we recommend its validity to be investigated using large studies with data recorded on smoking habits at multiple time points in life. The basic formulae described assume that the excess relative risk for a continuing smoker is linearly related to exposure and that the half-life is invariant of age. We describe model adaptations to allow for nonlinear dose-response and for age-dependence of the half-life. The negative exponential model, though relatively simple, appears to have many potential uses in epidemiological research for summarizing variations in risk with exposure changes.

Traffic-related air pollution and lung cancer: A meta-analysis

Background

We conducted a meta-analysis to evaluate the association between traffic-related air pollution and lung cancer in order to provide evidence for control of traffic-related air pollution.

Methods

Several databases were searched for relevant studies up to December 2013. The quality of articles obtained was evaluated by the Strengthening the Reporting of Observational Studies in Epidemiology checklist. Statistical analysis, including pooling effective sizes and confidential intervals, was performed.

Results

A total of 1106 records were obtained through the database and 36 studies were included in our analysis. Among the studies included, 14 evaluated the association between ambient exposure to traffic-related air pollution and lung cancer and 22 studies involved occupational exposure to air pollution among professional drivers. Twenty-two studies were marked A level regarding quality, 13 were B level, and one was C level. Exposure to nitrogen dioxide (meta-odds ratio [OR]: 1.06, 95% confidence interval [CI]: 0.99–1.13), nitrogen oxide (meta-OR: 1.04, 95% CI: 1.01–1.07), sulfur dioxide (meta-OR: 1.03, 95% CI: 1.02–1.05), and fine particulate matter (meta-OR: 1.11, 95% CI: 1.00–1.22) were positively associated with a risk of lung cancer. Occupational exposure to air pollution among professional drivers significantly increased the incidence (meta-OR: 1.27, 95% CI: 1.19–1.36) and mortality of lung cancer (meta-OR: 1.14, 95% CI: 1.04–1.26).

Conclusion

Exposure to traffic-related air pollution significantly increased the risk of lung cancer.

Systematic review with meta-analysis of the epidemiological evidence in the 1900s relating smoking to lung cancer

BACKGROUND

Smoking is a known lung cancer cause, but no detailed quantitative systematic review exists. We summarize evidence for various indices.

METHODS

Papers published before 2000 describing epidemiological studies involving 100+ lung cancer cases were obtained from Medline and other sources. Studies were classified as principal, or subsidiary where cases overlapped with principal studies. Data were extracted on design, exposures, histological types and confounder adjustment. RRs/ORs and 95% CIs were extracted for ever, current and ex smoking of cigarettes, pipes and cigars and indices of cigarette type and dose-response. Meta-analyses and meta-regressions investigated how relationships varied by study and RR characteristics, mainly for outcomes exactly or closely equivalent to all lung cancer, squamous cell carcinoma ("squamous") and adenocarcinoma ("adeno").

RESULTS

287 studies (20 subsidiary) were identified. Although RR estimates were markedly heterogeneous, the meta-analyses demonstrated a relationship of smoking with lung cancer risk, clearly seen for ever smoking (random-effects RR 5.50, CI 5.07-5.96) current smoking (8.43, 7.63-9.31), ex smoking (4.30, 3.93-4.71) and pipe/cigar only smoking (2.92, 2.38-3.57). It was stronger for squamous (current smoking RR 16.91, 13.14-21.76) than adeno (4.21, 3.32-5.34), and evident in both sexes (RRs somewhat higher in males), all continents (RRs highest for North America and lowest for Asia, particularly China), and both study types (RRs higher for prospective studies). Relationships were somewhat stronger in later starting and larger studies. RR estimates were similar in cigarette only and mixed smokers, and similar in smokers of pipes/cigars only, pipes only and cigars only. Exceptionally no increase in adeno risk was seen for pipe/cigar only smokers (0.93, 0.62-1.40). RRs were unrelated to mentholation, and higher for non-filter and handrolled cigarettes. RRs increased with amount smoked, duration, earlier starting age, tar level and fraction smoked and decreased with time quit. Relationships were strongest for small and squamous cell, intermediate for large cell and weakest for adenocarcinoma. Covariate-adjustment little affected RR estimates.

CONCLUSIONS

The association of lung cancer with smoking is strong, evident for all lung cancer types, dose-related and insensitive to covariate-adjustment. This emphasises the causal nature of the relationship. Our results quantify the relationships more precisely than previously.

Exposure to welding fumes increases lung cancer risk among light smokers but not among heavy smokers: evidence from two case-control studies in Montreal

We investigated relationships between occupational exposure to gas and arc welding fumes and the risk of lung cancer among workers exposed to these agents throughout the spectrum of industries. Two population-based case-control studies were conducted in Montreal. Study I (1979-1986) included 857 cases and 1066 controls, and Study II (1996-2001) comprised 736 cases and 894 controls. Detailed job histories were obtained by interview and evaluated by an expert team of chemist-hygienists to estimate degree of exposure to approximately 300 substances for each job. Gas and arc welding fumes were among the agents evaluated. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) of lung cancer using logistic regression, adjusting for smoking history and other covariates. The two studies provided similar results, so a pooled analysis was conducted. Among all subjects, no significant association was found between lung cancer and gas welding fumes (OR = 1.1; 95% CI = 0.9-1.4) or arc welding fumes (OR = 1.0; 95% CI = 0.8-1.2). However, when restricting attention to light smokers, there was an increased risk of lung cancer in relation to gas welding fumes (OR = 2.9; 95% CI = 1.7-4.8) and arc welding fumes (OR = 2.3; 95% CI = 1.3-3.8), with even higher OR estimates among workers with the highest cumulative exposures. In conclusion, there was no detectable excess risk of lung cancer due to welding fumes among moderate to heavy smokers; but among light smokers we found an excess risk related to both types of welding fumes.

Lung cancer risk among construction workers in California, 1988-2007

BACKGROUND

Although lung cancer risks can vary by race/ethnicity and by construction occupation, these risks have not been examined extensively.

METHODS

This study analyzed 110,937 lung cancer cases identified from the California Cancer Registry between 1988 and 2007. Mean age at diagnosis, proportion diagnosed at an advanced stage, and proportion with 3-year survival were calculated for lung cancer cases employed in the construction industry. Case-control methodology was also used to assess the risk of lung cancer. Morbidity odds ratios (MORs) were estimated by conditional logistic regression.

RESULTS

Construction workers were found to have a significantly elevated risk for all lung cancer combined (MOR = 1.57) and for each lung cancer histologic subtype examined. All construction occupations, except managers/engineers and supervisors, had a significantly elevated risk for all lung cancer combined. Roofers and welders had the highest risks for total lung cancer and for each of the histologic subtypes. Construction workers in each of the four race/ethnicity groups also had significantly increased lung cancer risks. Compared to non-construction workers, construction workers were diagnosed at an earlier age, at a more advanced stage, and had significantly lower 3-year survival, though differences were modest.

CONCLUSION

These findings justify additional reductions in carcinogenic exposures in construction, and increased support for smoking cessation programs at construction sites.

Lung cancer risk in painters: a meta-analysis

We conducted a meta-analysis to quantitatively compare the association between occupation as a painter and the incidence or mortality from lung cancer. PubMed and the reference lists of pertinent publications were searched and reviewed. For the meta-analysis, we used data from 47 independent cohort, record linkage, and case-control studies (from a total of 74 reports), including > 11,000 incident cases or deaths from lung cancer among painters. Three authors independently abstracted data and assessed study quality. The summary relative risk (meta-RR, random effects) for lung cancer in paint-ers was 1.35 [95% confidence interval (CI), 1.29-1.41; 47 studies] and 1.35 (95% CI, 1.21-1.51; 27 studies) after controlling for smoking. The relative risk was higher in never-smokers (meta-RR = 2.00; 95% CI, 1.09-3.67; 3studies) and persisted when restricted to studies that adjusted for other occupational exposures (meta-RR = 1.57; 95% CI, 1.21-2.04; 5 studies). These results support the conclusion that occupational exposures in painters are causally associated with the risk of lung cancer.

Meta-analyses of occupational exposure as a painter and lung and bladder cancer morbidity and mortality 1950-2008

The International Agency for Research on Cancer (IARC) classified occupational painting as a human carcinogen based on lung and bladder cancers; however, no specific exposures were implicated. The authors conducted comprehensive meta-analyses of the epidemiological literature on occupational painting and these cancers. The authors abstracted study results and confounder information, and used quantile plots and regression models to evaluate heterogeneity and publication bias. Summary risk estimates were derived and sensitivity analyses performed to evaluate smoking, socioeconomic status (SES), and exposure variables. Where applicable, a Bayesian approach was used to externally adjust for smoking, a major risk factor for both cancers. For lung cancer cohort mortality studies, publication bias and heterogeneity were seen, and earlier studies reported higher risk estimates than later studies. Overall lung cancer summary risk estimates were 1.29 for case-control and 1.22 and 1.36 for cohort morbidity and mortality studies, respectively, and risk estimates for bladder cancer were 1.28 for case-control and 1.14 and 1.27 for cohort morbidity and mortality studies, respectively (all statistically significant). Risks did not differ between painters and mixed occupations. Nonsignificant summary estimates resulted for lung and bladder cancers when controlling for SES, or externally adjusting for smoking in lung cancer studies. Summary risks varied by control source for case-control studies. Residual confounding by smoking and SES, lack of exposure group effect, and publication bias limit the ability of the meta-analyses to explain associations observed between occupational painting and lung and bladder cancers. Given the long latencies for lung and bladder cancers, these weak associations, if real, may not be elucidated through studies of occupational painting today.

Lung cancer risk in painters: a meta-analysis

OBJECTIVE

We conducted a meta-analysis to quantitatively compare the association between occupation as a painter and the incidence or mortality from lung cancer.

DATA SOURCES

PubMed and the reference lists of pertinent publications were searched and reviewed. For the meta-analysis, we used data from 47 independent cohort, record linkage, and case control studies (from a total of 74 reports), including > 11,000 incident cases or deaths from lung cancer among painters.

DATA EXTRACTION

Three authors independently abstracted data and assessed study quality.

DATA SYNTHESIS

The summary relative risk (meta-RR, random effects) for lung cancer in painters was 1.35 [95% confidence interval (CI), 1.291.41; 47 studies] and 1.35 (95% CI, 1.211.51; 27 studies) after controlling for smoking. The relative risk was higher in never-smokers (meta-RR = 2.00; 95% CI, 1.093.67; 3 studies) and persisted when restricted to studies that adjusted for other occupational exposures (meta-RR = 1.57; 95% CI, 1.212.04; 5 studies). The results remained robust when stratified by study design, sex, and study location and are therefore unlikely due to chance or bias. Furthermore, exposure response analyses suggested that the risk increased with duration of employment.

CONCLUSION

These results support the conclusion that occupational exposures in painters are causally associated with the risk of lung cancer.

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.

Endotoxin exposure and lung cancer risk: a systematic review and meta-analysis of the published literature on agriculture and cotton textile workers

Objective

To examine the association between exposure to endotoxins and lung cancer risk by conducting a systematic review and meta-analysis of epidemiologic studies of workers in the cotton textile and agricultural industries; industries known for high exposure levels of endotoxins.

Methods

Risk estimates were extracted from studies published before 2009 that met predefined quality criteria, including 8 cohort, 1 case–cohort, and 2 case–control studies of cotton textile industry workers, and 15 cohort and 2 case–control studies of agricultural workers. Summary risk estimates were calculated using random effects meta-analyses. Potential sources of heterogeneity were explored through subgroup analyses.

Results

The summary risk of lung cancer was 0.72 (95% CI, 0.57–0.90) for textile workers and 0.62 (0.52–0.75) for agricultural workers. The relative risk of lung cancer was below 1.0 for most subgroups defined according to sex, study design, outcome, smoking adjustment, and geographic area. Two studies provided quantitative estimates of endotoxin exposure and both studies tended to support a dose–dependent protective effect of endotoxins on lung cancer risk.

Conclusion

Despite several limitations, this meta-analysis based on high-quality studies adds weight to the hypothesis that occupational exposure to endotoxin in cotton textile production and agriculture is protective against lung cancer.

Identification of occupational cancer risk in British Columbia: a population-based case-control study of 2,998 lung cancers by histopathological subtype

BACKGROUND

Few studies have investigated occupational lung cancer risk in relation to specific histopathological subtypes.

METHODS

A case-control study was conducted to evaluate the relationship between lung cancer and occupation/industry of employment by histopathological subtype. A total of 2,998 male cases and 10,223 cancer controls, diagnosed between 1983 and 1990, were identified through the British Columbia Cancer Registry. Matched on age and year of diagnosis, conditional logistic regression analyses were performed for two different estimates of exposure with adjustment for potentially important confounding variables, including tobacco smoking, alcohol consumption, marital status, educational attainment, and questionnaire respondent.

RESULTS

For all lung cancers, an excess risk was observed for workers in the primary metal (OR = 1.31, 95% CI, 1.01-1.71), mining (OR = 1.53, 95% CI, 1.20-1.96), machining (OR = 1.33, 95% CI, 1.09-1.63), transport (OR = 1.50, 95% CI, 1.08-2.07), utility (OR = 1.60, 95% CI, 1.22-2.09), and protective services (OR = 1.27, 95% CI, 1.05-1.55) industries. Associations with histopathological subtypes included an increased risk of squamous cell carcinoma in construction trades (OR = 1.25, 95% CI, 1.06-1.48), adenocarcinoma for professional workers in medicine and health (OR = 1.73, 95% CI, 1.18-2.53), small cell carcinoma in railway (OR = 1.62, 95% CI, 1.06-2.49), and truck transport industries (OR = 1.51, 95% CI, 1.00-2.28), and large cell carcinoma for employment in the primary metal industry (OR = 2.35, 95% CI, 1.11-4.96).

CONCLUSIONS

Our results point to excess lung cancer risk for occupations involving exposure to metals, polyaromatic hydrocarbons and asbestos, as well as several new histopathologic-specific associations that merit further investigation.

Occupations and lung cancer: a population-based case-control study in British Columbia

An investigation based on a large population-based case-control study in British Columbia, Canada, was conducted to identify high-risk occupations for lung cancer by histological subtypes. Subjects were 14,755 male incident cancer cases for whom lifetime occupational histories and information on smoking and relevant covariates were collected. Occupational associations for 2998 lung cancer cases, including histological subtypes, were assessed by logistic regression using other cancer cases, excluding smoking-related cancers, as controls. An excess risk of lung cancer was found among workers in metal processing, bakers, and ship deck crew for all histological subtypes, and construction workers, chefs and cooks, and medical workers for specific histological subtypes. Occupational associations that are unique to histological subtypes of lung cancer were identified. Owing to a scarcity of literature in this area, future research needs to focus on confirming these histological associations, and identifying the risk from key exposures found within these occupations (e.g., medical radiation, electromagnetic fields, and cooking fumes).

Sampling and analytical method development and hand wipe measurements of dermal exposures to polycyclic aromatic hydrocarbons

This article describes the laboratory assessment of a hand and surface wipe sampling method for polycyclic aromatic hydrocarbons (PAHs). The analytical method employed extraction of the wipe samples into dimethyl sulfoxide (DMSO) and high-performance liquid chromatography (HPLC) flourometric detection of pyrene, a predominant PAH in used gasoline engine oils (UGEO). Recovery of pyrene was evaluated for two different sampling media by first contaminating the hands of a small number of volunteers with UGEO, followed by applying a small amount of corn oil to the palms, and by wiping the skin with a Whatman cellulostic filter paper or a polyester fabric wipe (i.e., Alpha wipes). In summary, using either Whatman or Alpha wipes, the mean recovery of pyrene from the UGEO that was applied to the hands and contained within three consecutive wipes was 69% and 54%, respectively. However, the relative recovery of the first to second wipe was on average 47% and 75% for the two media, respectively. These results indicate that the Alpha wipes were more efficient at recovering pyrene in the first wipe but less efficient overall when all three consecutive samples were included. Even though this sampling was performed in a controlled laboratory environment, the minimum and maximum amount of pyrene recovered in the individual composite samples using either method spanned a range of twofold. Overall, intra-and interpersonal variability, as measured by coefficient of variation, were 22% and 19%, respectively, and were not statistically different by type of media used. This method was used in a pilot field survey to sample the hands of 18 automotive repair technicians and 18 office workers. Detectable amounts of pyrene (>0.2 microg/sample) were found on the hands of 61% and 0% of these two groups, respectively, with the highest measured quantity equal to 1.06 microg. Samples from the upper surfaces of automobile motors were generally low to nondetectable (<0.027 microg/sample), while the median value of 0.047 mkcrlg/50 cm(2)(CV = 160%) and up to 0.640 microg were found on the drip pans.

Occupational Exposures and Risk of Adenocarcinoma of the Lung in Uruguay

OBJECTIVES

To investigate occupational risks of lung adenocarcinoma in Uruguay and to confirm a previously reported increased risk among butchers.

METHODS

We conducted a case-control study among men in four major hospitals in Montevideo, based on interviews to 338 cases of lung adenocarcinoma and 1014 hospital-based controls. We calculated odds ratios (ORs) of lung adenocarcinoma for employment in 22 jobs, after adjustment for tobacco smoking and other potential confounders.

RESULTS

The OR was increased for employment as farmer, tractor driver, painter and medical worker, but no trend was suggested for duration of employment. Long-term employment as mason, glass worker or textile worker resulted in an increased OR. The OR for employment as butcher was 1.2 (95% confidence interval 0.7-2.1). The OR increased with increasing duration of self-reported exposure to formaldehyde.

CONCLUSIONS

Occupational exposures seem to play a limited role in causing lung adenocarcinoma among men in Uruguay. Employment as butcher was not confirmed as an important risk factor.

Occupational exposures and lung cancer in New Caledonia

AIMS

To study the associations between occupational exposures and the risk of lung cancer in New Caledonia.

METHODS

All cases diagnosed between January 1993 and December 1995 (228 lung cancers) and 305 population controls were included. Detailed information on lifetime job history, smoking, and other potential risk factors was collected by interview. Occupational exposures were assessed from the questionnaires by an industrial hygienist, without knowledge of case-control status.

RESULTS

No significant association was found with exposures related to nickel mining and refining, the main industrial activity in the territory. Among men, an excess risk of lung cancer was found for bus and truck drivers. Increased risks were also observed in men with the highest level of cumulative exposure to cleaning products and inorganic fertilisers. Exposure to field dust was associated with lung cancer risk in both sexes, and risk increased with cumulative exposure level. In some areas tremolite asbestos derived from local outcroppings was used as a whitewash. The association between exposure to field dust and lung cancer was limited to men and women exposed to this whitewash-that is, living in areas where the soil may contain tremolite.

CONCLUSION

This study shows several associations between occupational exposures and lung cancer. The findings suggest that exposure to tremolite fibres from cultivated fields may increase the risk of lung cancer in New Caledonia.

Occupation and smoking as risk factors for lung cancer: a population-based case-control study

BACKGROUND

Lung cancer is associated with occupation, but not much is known about the influence exerted on risk by length of exposure and the joint effect of occupational exposure and tobacco on risk of lung cancer.

METHODS

Through a population-based case-control study, we defined risk professions as those that have been associated previously with higher risk of lung cancer.

RESULTS

The relative risk seems to increase linearly and significantly with the number of years spent in risk occupations, rising significantly by 28% for every 10 years in a risk profession. Should such occupations be combined with exposure to a smoking habit, then in the case of heavy smokers, a working career spanning 20 years or more in risk occupations would mean tripling the possibility of developing lung cancer from occupation.

CONCLUSIONS

The high risks observed indicate a public health problem and indicate that joint exposure to risk professions and tobacco ought to be avoided. We must stress from these results the need for effective education for all workers.

Occupational exposures and lung cancer in Buenos Aires, Argentina

The main objective of this study was to analyze the risks associated with occupational exposures in an industrializing country where lung cancer is the primary neoplastic cause of death in men. A full occupational history was collected through interviewing 199 men with lung cancer and 393 control subjects. Exposure to arsenic, asbestos, chromium, dust, nickel, and polynuclear aromatic hydrocarbons was assessed by means of a job-exposure matrix. Elevated odds ratios were observed for employment in the alcoholic beverages industry (5.2; 95% confidence interval [CI], 1.1 to 23.1), sawmills and wood mills (4.8; 95% CI, 1.2 to 19.0), water transport (3.3; 95% CI, 1.1 to 12.1), and chemicals/plastics manufacturers (1.9; 95% CI, 1.1 to 3.3). A small, non-significant increased risk was observed after long-term exposure to arsenic and chromium, with a dose-response for chromium. Although some of the present results may result from chance, most are consistent with those of previous investigations in other countries.