Proportion of lung cancers due to occupational exposure

Towards a more effective REACH legislation in protecting human health

There is growing evidence indicating the substantial contribution of man-made products to an increase in the risk of diseases of civilization. In this article, the Belgian Scientific Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) Committee gives a critical view on the working of REACH. The current regulatory framework needs to further evolve taking into account data generated using modern science and technology. There is a need for improved assessment process not only before but also after entering the market. Objectivity, transparency, and the follow-up after market access can be optimized. Additionally, no guidance documents exist for regulation of mixture effects. Further, the lengthiness before regulatory action is a big concern. Decision-making often takes several years leading to uncertainties for both producers and end users. A first proposed improvement is the implementation of independent toxicity testing, to assure objectivity, transparency, and check and improve compliance. A "no data, no market" principle could prevent access of hazardous chemicals to the market. Additionally, the introduction of novel testing could improve information on endpoints such as endocrine disrupting abilities, neurotoxicity, and immunotoxicity. An adapted regulatory framework that integrates data from different sources and comparing the outputs with estimates of exposure is required. Fast toxicology battery testing and toxicokinetic testing could improve speed of decision-making. Hereby, several improvements have been proposed that could improve the current REACH legislation.

Incident Lung Cancer Survival. Long-Term Follow-Up of a Population-Based Study in Italy

The long-term survival of an incident lung cancer population was evaluated in relation to clinical stage, treatment modalities and other prognostic factors. The survey was carried out among the residents in the Local Sanitary Unit of Saronno, a highly industrialized area of northern Italy, where all the lung cancer cases diagnosed during the years 1976-79 had been identified and clinically studied. The overall survival of the 222 cases included in the analysis was 32% at 1 year, 10% at 3 years and 5% at 5 years; median survival was 7 months. A significantly better prognosis was associated with surgical resection (32% at 5 years; median, 42 mo), clinical stage I (16% at 5 years; median, 15 mo), and squamous cell carcinoma (13% at 5 years; median, 11 mo). Other factors such as age, sex, social class or cancer symptoms did not affect survival when treatment was taken into account. Our data show that surgical resection is the major determinant of survival, and suggest that suboptimal access to curative treatment, particularly in patients aged 60 to 75 with limited disease, might have compromised the overall survival.

Additive Synergism between Asbestos and Smoking in Lung Cancer Risk: A Systematic Review and Meta-Analysis

Smoking and asbestos exposure are important risks for lung cancer. Several epidemiological studies have linked asbestos exposure and smoking to lung cancer. To reconcile and unify these results, we conducted a systematic review and meta-analysis to provide a quantitative estimate of the increased risk of lung cancer associated with asbestos exposure and cigarette smoking and to classify their interaction. Five electronic databases were searched from inception to May, 2015 for observational studies on lung cancer. All case-control (N = 10) and cohort (N = 7) studies were included in the analysis. We calculated pooled odds ratios (ORs), relative risks (RRs) and 95% confidence intervals (CIs) using a random-effects model for the association of asbestos exposure and smoking with lung cancer. Lung cancer patients who were not exposed to asbestos and non-smoking (A-S-) were compared with; (i) asbestos-exposed and non-smoking (A+S-), (ii) non-exposure to asbestos and smoking (A-S+), and (iii) asbestos-exposed and smoking (A+S+). Our meta-analysis showed a significant difference in risk of developing lung cancer among asbestos exposed and/or smoking workers compared to controls (A-S-), odds ratios for the disease (95% CI) were (i) 1.70 (A+S-, 1.31-2.21), (ii) 5.65; (A-S+, 3.38-9.42), (iii) 8.70 (A+S+, 5.8-13.10). The additive interaction index of synergy was 1.44 (95% CI = 1.26-1.77) and the multiplicative index = 0.91 (95% CI = 0.63-1.30). Corresponding values for cohort studies were 1.11 (95% CI = 1.00-1.28) and 0.51 (95% CI = 0.31-0.85). Our results point to an additive synergism for lung cancer with co-exposure of asbestos and cigarette smoking. Assessments of industrial health risks should take smoking and other airborne health risks when setting occupational asbestos exposure limits.

Occupational asbestos exposure and lung cancer--a systematic review of the literature

The objective of this study was to evaluate the scientific literature concerning asbestos and lung cancer, emphasizing low-level exposure. A literature search in PubMed and Embase resulted in 5,864 citations. Information from included studies was extracted using SIGN. Twenty-one statements were evidence graded. The results show that histology and location are not helpful in differentiating asbestos-related lung cancer. Pleural plaques, asbestos bodies, or asbestos fibers are useful as markers of asbestos exposure. The interaction between asbestos and smoking regarding lung cancer risk is between additive and multiplicative. The findings indicate that the association between asbestos exposure and lung cancer risk is basically linear, but may level off at very high exposures. The relative risk for lung cancer increases between 1% and 4% per fiber-year (f-y)/mL, corresponding to a doubling of risk at 25-100 f-y/mL. However, one high-quality case-control study showed a doubling at 4 f-y/mL.

Population Attributable Risk for Occupational Gancer in Italy

Population studies estimating the proportion of cancer attributable to occupation (PAR) in different geographical areas in Italy are reviewed. Studies using lists of industrial activities and occupations which are known or suspected to entail exposure to lung carcinogens gave lung cancer PARs between 5% and 36%. Those using job-exposure matrices estimated PARs of 3%-53%, with most of the values ranging between 17 and 33%. For bladder cancer, PARs ranged between 4% and 24%. The uses and limitations of calculating population attribultable risk are discussed.

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.

Carcinogenicity of occupational nickel exposures: an evaluation of the epidemiological evidence

The health effects documented in recent epidemiological studies of nickel-exposed workers relate to past exposures, mostly of unknown magnitude and unknown nickel speciation. Major studies have been carried out at nickel smelters and refineries. Although each study suffers from some deficiencies, as is common in such retrospective studies, the findings in concert strongly indicate that nickel emitted from the calcining and sintering operations is a potent carcinogen resulting in nasal and pulmonary cancers. Some risk appears to be present in other refinery operations, such as Orford furnace, copper and nickel sulfate, and crushing departments, and one study has suggested a risk associated with soluble nickel compounds in the electrolysis department, although this finding has not been confirmed. Only one study demonstrated an exposure-response relationship, which, however, was not statistically significant. Other studies showed a relationship between increased exposure time and augmented cancer risk. In nickel-using industries, no excess cancer related to nickel exposures has been demonstrated beyond doubt; concurrent exposures to other potential carcinogens constitute a confounding variable that makes interpretation difficult. However, the studies have not excluded that a cancer hazard may be present outside the nickel-producing facilities. Further, case-referent studies of respiratory cancers suggest that a nickel-related etiology may well exist in the nickel-using industries. As the exact identity of the carcinogenic form or forms of nickel remains unknown, exposure to all nickel compounds should be kept as low as reasonably achievable.

A Bayesian approach to assess interaction between known risk factors: the risk of lung cancer from exposure to asbestos and smoking

We review the literature on the combined effect of asbestos exposure and smoking on lung cancer, and explore a Bayesian approach to assess evidence of interaction. Previous approaches have focussed on separate tests for an additive or multiplicative relation. We extend these approaches by exploring the strength of evidence for either relation using approaches which allow the data to choose between both models. We then compare the different approaches.

The sociobiologic integrative model (SBIM): enhancing the integration of sociobehavioral, environmental, and biomolecular knowledge in urban health and disparities research

Disentangling the myriad determinants of disease, within the context of urban health or health disparities, requires a transdisciplinary approach. Transdisciplinary approaches draw on concepts from multiple scientific disciplines to develop a novel, integrated perspective from which to conduct scientific investigation. Most historic and contemporary conceptual models of health were derived either from the sociobehavioral sciences or the biomolecular sciences. Those models deriving from the sociobehavioral sciences generally lack detail on involved biological mechanisms whereas those derived from the biomolecular sciences largely do not consider socioenvironmental determinants. As such, advances in transdisciplinary characterizations of health in complex systems like the urban environment or health disparities may be impeded. This paper suggests a sociobiologic organizing model that encourages a multilevel, integrative perspective in the study of urban health and health disparities.

Asbestos Exposure, Manganese Superoxide Dismutase (MnSOD) Genotype, and Lung Cancer Risk

To assess whether differences in genetic susceptibility to oxidative stress modify asbestos-related lung cancer risk (caused by lung inflammation, free radical production), we examined possible interactions between manganese superoxide dismutase (MnSOD) genotypes and asbestos in a hospital-based case-control study of 811 white lung cancer cases and 957 friend/spouse controls. Cumulative lifetime asbestos exposure score (AES) was calculated from self-reported duration and intensity of occupational and nonoccupational exposures. A total of 13.5% of cases and 10% of controls had "high" AES (determined by a priori cut point). The homozygous variant MnSOD genotype was associated with increased lung cancer risk among individuals with zero or "low" AES (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.52-3.01) and no association (OR = 1.00; 95% CI = 0.36-2.73) among the "high" AES group. We observed no statistically significant interaction between MnSOD genotype and asbestos exposure for lung cancer risk.

Relation between exposure to asbestos and smoking jointly and the risk of lung cancer

OBJECTIVES

To review evidence about the joint relation of exposure to asbestos and smoking on the risk of lung cancer to answer three questions: (1) does asbestos increase risk in non-smokers; (2) are the data consistent with an additive model; and (3) are the data consistent with a multiplicative model?

METHODS

Analysis of 23 studies reporting epidemiological evidence on the joint relation. Comparison of risk of lung cancer in subjects unexposed to asbestos or smoking, exposed to asbestos only, to smoking only, or to both. Estimation of the relative risk associated with asbestos exposure in non-smokers and of statistics testing for additivity and multiplicativity of risk.

RESULTS

Eight of the 23 studies provided insufficient data on the risk of lung cancer in non-smokers to test for possible effects of asbestos. Asbestos exposure was associated with a significantly (p<0.05) increased risk in non-smokers in six of the remaining studies and with a moderately increased, but not significant, increase in a further six. In two of the three studies that found no increase, asbestos exposure was insufficient to increase risks in smokers. In 30 of 31 data sets analysed, risk in the combined exposure group was greater than predicted by the additive model. There was no overall departure from the multiplicative model, the proportional increase in risk of lung cancer with exposure to asbestos being estimated as 0.90 (95% confidence interval (95% CI) 0.67 to 1.20) times higher in smokers than non-smokers. For two studies significant (p<0.05) departures from a multiplicative relation were found in some, but not all, analyses. Reasons are presented why these may not indicate true model discrepancies.

CONCLUSIONS

Asbestos exposure multiplies risk of lung cancer by a similar factor in non-smokers and smokers. The extent to which it multiplies risk varies between studies, no doubt depending on the type of asbestos involved, and the nature, extent, and duration of exposure.

Occupational risk factors of lung cancer: a hospital based case-control study

OBJECTIVES

To investigate the relation between lung cancer and exposure to occupational carcinogens in a highly industrialised region in western Europe.

METHODS

In a case-control study 478 cases and 536 controls, recruited from 10 hospitals in the Antwerp region, were interviewed. Cases were male patients with histologically confirmed lung cancer; controls were male patients without cancer or primary lung diseases. Data were collected by questionnaires to obtain information on occupations, exposures, and smoking history. Job titles were coded with the Office of Populations, Censuses and Surveys industrial classification. Exposure was assessed by self report and by job-task exposure matrix. Exposure odds ratios were calculated with logistic regression analysis adjusted for age, smoking history, and marital and socio-economic status.

RESULTS

A job history in the categories manufacturing of transport equipment other than automobiles (for example, shipyard workers), transport support services (for example, dockers), and manufacturing of metal goods (for example, welders) was significantly associated with lung cancer (odds ratios (ORs) 2.3, 1.6, and 1.6 respectively). These associations were independent of smoking, education, civil, and economic status. Self reported exposure to potential carcinogens did not show significant associations with lung cancer, probably due to nondifferential misclassification. When assessed by job-task exposure matrix, exposure to molybdenum, mineral oils, and chromium were significantly associated with lung cancer. A strong association existed between smoking and lung cancer: OR of ex-smokers 4.2, OR of current smokers 14.5 v non-smokers. However, smoking did not confound the relation between occupational exposure and lung cancer.

CONCLUSIONS

The study has shown a significant excess risk of lung cancer among workers in manufacturing of metal goods, manufacturing of transport equipment (other than automobiles), and transport support services. Assessment of exposure to specific carcinogens resulted in significant associations of chromium, mineral oils, and molybdenum with lung cancer. This study is, to our knowledge, the first study reporting a significant association between occupational exposure to molybdenum and lung cancer.

Lung cancer and occupational risk factors in Greece

This study estimated the proportion of lung cancer in Greece that was attributable to occupational exposure. Two hundred eighty-two patients with lung cancer and 494 controls were interviewed about their socioeconomic characteristics, sex, age, and occupational, smoking, and residential histories. Each subject was classified as exposed or unexposed to known occupational lung carcinogens. Because of the small number of females exposed, only males were included in the multivariate analyses. When the occupationally exposed subjects were compared with the unexposed subjects and an adjustment for smoking was made, the relative risk for lung cancer was 2.9 (95% confidence interval, 1.95-4.31). If 5% to 10% of the Greek population were occupationally exposed, the attributable risk would be 9.9% to 16.6%, respectively. Occupational exposures conferred an additional risk that was approximately threefold that of smoking alone. Risks increased in a dose-response fashion with increasing cigarette consumption.

Lung and bladder cancer in a Norwegian municipality with iron and steel producing industry: population based case-control studies

OBJECTIVES

To investigate the influence of occupation on the rising incidence of lung and bladder cancer among men in a Norwegian municipality where an iron and steel plant constituted the key industry between 1955 and 1989.

METHODS

Based on the lung cancer cases reported to the Cancer Registry of Norway from 1980 to 1992 a population based case-control study was performed, including 86 cases and 196 controls. Information on occupations and smoking habits was collected through interviews and from the personnel files from the industrial plants. A case-control study on bladder cancer with 52 cases and 156 controls was carried out to cast light on the role of polycyclic aromatic hydrocarbons (PAHs).

RESULTS

An odds ratio (OR) for lung cancer of 2.9 (95% confidence interval (95% CI) 1.2 to 6.7) was associated with exposure to PAHs. Based on data from personnel files, increased risk of lung cancer (OR 2.8 95% CI 1.1 to 7.0) was associated with work experience in the pig iron department at the ironworks. A non-significant OR of 1.8 was associated with exposure to asbestos. Bladder cancer was not associated with exposure to PAHs at the iron, steel, and coke plant, or with experience from any of the production departments at the plant.

CONCLUSIONS

One fifth of the lung cancer cases were attributed to exposure to PAHs or asbestos. More than 80% of the cases of lung cancer were attributed to tobacco smoking. The cancer risk in the pig iron department may be due to a combination of exposures to PAH, asbestos, or dust of mixed composition.

Socioeconomic status and lung cancer incidence in men in The Netherlands: is there a role for occupational exposure?

STUDY OBJECTIVE

To evaluate the influence of occupational exposure to carcinogens in explaining the association between socioeconomic status and lung cancer.

DESIGN

A prospective cohort study. Data on diet, other lifestyle factors, sociodemographic characteristics and job history were collected by means of a self administered questionnaire. Follow up for incident cancer was established by record linkage with a national pathology register and with regional cancer registries.

SETTING

Population originating from 204 municipalities in The Netherlands.

PARTICIPANTS

These comprised 58 279 men aged 55-69 years in September 1986. After 4.3 years of follow up there were 470 microscopically confirmed incident lung cancer cases with complete data on dietary habits and job history.

MEASUREMENTS AND MAIN RESULTS

Estimation of occupational exposure to asbestos, paint dust, polycyclic aromatic hydrocarbons, and welding fumes was carried out by two experts, using information on job history from the baseline questionnaire. Socioeconomic status was measured by means of highest attained level of education and two indicators based on occupation. In the initial multivariate analyses of socioeconomic status and lung cancer, adjustment was made for age, smoking habits, intake of vitamin C, beta-carotene and retinol, and history of chronic obstructive pulmonary disease or asthma. Additional adjustment for occupational exposure to the four carcinogens mentioned above did not change the inverse association between the level of education and lung cancer risk (initial model: RR highest/lowest level of education = 0.53; 95% CI 0.34, 0.82; additional model: RR highest/lowest level of education = 0.53; 95% CI 0.34, 0.84). Nor was the association between the two occupation based indicators of socioeconomic status and lung cancer risk influenced by occupational exposure to carcinogens. The effect of occupational exposure on the association between the level of education and lung cancer risk did not differ between ex-smokers and current smokers.

CONCLUSIONS

Occupational exposure to asbestos, paint dust, polycyclic aromatic hydrocarbons, and welding fumes could not explain the inverse association between socioeconomic status and lung cancer risk. More research which explicitly addresses possible explanations for the association between socioeconomic status and lung cancer risk is needed.

The epidemiology of lung cancer: review of risk factors and Spanish data

Lung cancer is the main form of cancer among men both in Spain and in the rest of europe. However, Spanish incidence rates are among the lowest of the European registries, especially for women. In this country, lung cancer mortality increased much more rapidly for men than for women between the fifties and the eighties. This increase was larger for lung cancer than for any other site. The trend of incidence, in Spain as well as in the greatest part of the world, is entirely explained by tobacco consumption, which remains the major risk factor for lung cancer. Occupational radon and asbestos exposures are other important but less extended determinants of lung cancer. Genetic factors could also play a role in the occurrence of the disease. On the other side, a high consumption of fruit and vegetables is protective, but, so far, no single dietary component has been found to be preventive. In this article, we review the major risk factors of lung cancer with an emphasis on Spanish and European data.

Differences in cancer incidence and mortality among socio-economic groups

OBJECTIVES

In this article studies on the association between socioeconomic status (SES) and risk for cancer at different sites are reviewed.

METHODS

The review is restricted to studies conducted in affluent societies, after 1970. Only studies using income, education and/or occupation as SES indicators are included.

RESULTS

A more or less consistent positive association between SES and cancer risk was found for colon and breast cancer. More or less consistent inverse associations were found for lung, stomach, oropharyngeal and esophageal cancer. Inconsistent associations were reported for cancer of the rectum and pancreas. Possible explanations for SES differences in cancer risk are discussed with special emphasis on lifestyle variables related to cancer risk.

CONCLUSIONS

It is concluded that it is still unclear whether the reported associations can be (partially) attributed to lifestyle related risk factors for cancer such as smoking, nutritional habits, drinking habits and reproductive factors.

Lung cancer: is there an association with socioeconomic status in The Netherlands?

STUDY OBJECTIVE

To evaluate if there are differences in lung cancer incidence between socioeconomic groups in the Netherlands and if so, if smoking habits and other lifestyle characteristics could explain these differences.

DESIGN

Prospective cohort study. Baseline measurement included information on socioeconomic status, smoking habits, and other covariates by means of a self-administered questionnaire. Follow up was established by computerised record linkage to cancer registries and a pathology register.

SETTING

Population originating from 204 municipalities in The Netherlands.

PARTICIPANTS

58,279 men aged 55-69 years in September 1986. After 3.3 years of follow up 490 microscopically confirmed incident lung cancer cases were detected.

MAIN RESULTS

An inverse association between lung cancer risk and highest level of education was found, which persisted after adjustment for age, smoking, dietary intake of vitamin C, beta-carotene and retinol (rate ratio (RR) highest/lowest level of education = 0.52, 95% CI 0.33, 0.82, trend p < 0.001). Men with a lower white collar profession had a significantly lower relative rate of lung cancer compared with blue collar workers (RR = 0.66, 95% CI 0.47, 0.96), but after adjustment for smoking habits this difference was reduced (RR = 0.73, 95% CI 0.51, 1.08).

CONCLUSIONS

There is an inverse association between highest level of education and lung cancer, which is still apparent after adjustment for age, smoking, dietary intake of vitamin C, beta-carotene and retinol. The significantly lower lung cancer risk of lower white collar workers compared with the risk of blue collar workers could be partially explained by smoking habits.

Insulation, asbestos, smoking habits, and lung cancer cell types

The association between occupational exposure to asbestos and histological type of lung cancer was analyzed in a multicenter hospital-based case-control study (2,871 male cases and 5,240 male controls) conducted from 1981-1991. Twenty-two percent of cases and 18% of controls were employed in asbestos-related occupations for at least 1 year. Most of these asbestos jobs were in the construction field. The odds ratio (OR) among current smokers was 1.0 [95% confidence intervals (CI) 0.9 to 1.3]; for ex-smokers, the OR was 1.4 (95% CI 1.1 to 1.6). In contrast, 10% of cases and 5% of controls self-reported that they were chronically exposed to asbestos for at least 1 year. Self-reported asbestos exposure was significantly related to all lung cancer cell types among smokers and ex-smokers, although a trend in the ORs with duration of self-reported exposure was not found for current smokers. Among 48 cases and 52 controls reporting distinct exposure to building insulation, the OR was 2.2 (95% CI 1.2 to 4.3) for current smokers, and 1.8 (95% CI 0.9 to 3.6) for ex-smokers, compared to subjects who were not exposed to building insulation and asbestos. A nonsignificant association with self-reported exposure to asbestos was observed for a small number of never smokers (eight of 83 nonsmoking cases, OR = 2.0, 95% CI 0.9 to 4.6). When examining these results and their causal implications, possible misclassification and reporting biases need to be considered.

[Occupational exposure and lung cancer in smokers]

High male lung cancer incidence and mortality in Rosario city, Argentina, have been found in previous studies. A project was undertaken for the purpose of evaluating the life-time occupational history as well as the duration and intensity of cigarette smoking as determinants of histologic cell types in 211 male patients with primary lung cancer. Their histologic cell types were: squamous 39%, adenocarcinoma 29%, small cell 18%, and others and not specified 14%. An association was found between histologic cell types and occupations (p < 0.0001), adenocarcinoma being more prevalent in office personnel, teachers, accountants, lawyers, and squamous in the other, supposedly dirtier working environments, mainly in those men who had begun to work in farming and later transferred to mechanics and metallurgy. These latter ones were diagnosed at a younger age than those in other occupations, with a significant difference for squamous and small cell. No differences in the smoking intensity were found between the occupational groups. The mean age these patients began to smoke at was 15 years for those with squamous and small cell, and 17 years for those with adenocarcinoma (p < 0.001). An interesting finding was the difference at their mean-age at diagnosis, 58 years for smokers and 68 for ex-smokers (p < 0.0001). Studies are needed to elucidate the interplay of risk factors in the etiology of histologic subtypes of lung cancer.

Occupation and lung cancer risk among women in northern China

Lifetime occupational histories were obtained in a case-control study of 965 female lung cancer patients and 959 controls selected from the general population in Shenyang and Harbin, People's Republic of China, where most women have worked outside the home. After adjusting for smoking, we found a significantly increased risk of lung cancer associated with employment involving the manufacture of transportation equipment (OR = 1.6, 95% CI = 1.0, 2.6), in particular the manufacturing of automobiles (OR = 3.0, 95% CI = 1.4, 6.4). Metal smelting and treatment workers were at an increased risk of lung cancer (OR = 1.5, 95% CI = 1.0, 2.1); the highest risks were observed among metal surfacers (OR = 3.1, 95% CI = 1.1, 9.0) and currently employed foundry workers (OR = 13.0, 95% CI = 1.7, 99.4). On the other hand, about a 50% decreased risk of lung cancer was observed among those employed in textile industries or as leaders of state and party organizations. Based on self-reports, exposures to coal dust and smoke from burning fuel at the workplace were also significant risk factors. The findings were similar when the analyses were confined to nonsmokers and were comparable across the major cell types of lung cancer.

Occupational exposure and lung cancer risk in a coastal area of northeastern Italy

A case-control study of lung cancer and occupational exposure was conducted in a coastal area of Northeastern Italy where metallurgical and mechanical industries, docks and shipyards are located. Cases comprised 756 men who died of primary lung cancer in a 5-year period. Controls comprised 756 male subjects dying from other causes during the same period. Occupational exposures to lung carcinogens were assessed according to a job title-based approach, using two separate lists of industries/occupations recognized as being causally associated (list A) or suspected of being causally associated (list B) with lung cancer in humans. Exposure to asbestos was classified as absent, possible, or definite. After adjustment for cigarette smoking and place of residence, a significant association was found between lung cancer and occupations in both list A [relative risk (RR) = 2.25, 95% confidence interval (CI) = 1.68-3.03] and list B (RR = 1.33, 95% CI = 1.03-1.71). A significant excess risk was found for workers with definite exposure to asbestos as compared to those with no exposure to lung carcinogens (RR = 1.98, 95% CI = 1.42-2.75). Among occupations with recognized exposure to lung carcinogens other than asbestos, a significant excess risk for lung cancer was observed in iron and metalware workers. In occupational groups with definite exposure to asbestos, elevated risk estimates were found for shipyard workers, dockworkers, carpenters, and electricians. The combined effect of smoking and asbestos was found to be compatible with that expected under a multiplicative model. The overall population-attributable risk (ARp) for cigarette smoking was found to be 87.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Lung cancer and occupation: results of a multicentre case-control study

The objective of the current study was to estimate the risk of lung cancer attributable to occupational factors and not due to tobacco. At 24 hospitals in nine metropolitan areas in the United States, 1793 male lung cancer cases were matched for race, age, hospital, year of interview, and cigarette smoking (never smoker, ex-smoker, smoker (1-19 and > or = 20 cigarettes per day)) to two types of controls (cancer and non-cancer hospital patients). Information on usual occupation, exposure to specific potential carcinogens, and cigarette smoking was obtained by interview. Risk of lung cancer was increased significantly for electricians; sheetmetal workers and tinsmiths; bookbinders and related printing trade workers; cranemen, derrickmen, and hoistmen; moulders, heat treaters, annealers and other heated metal workers; and construction labourers. All of these occupations are potentially exposed to known carcinogens. Odds ratios (ORs) were increased for exposure to coal dust (adjusted OR = 1.5; 95% confidence interval (95% CI) 1.1-2.1). After stratification, this association was statistically significant only after 10 or more years of exposure. Lung cancer was also related to exposure to asbestos (adjusted OR = 1.8; 95% CI 1.5-2.2). The ORs increased with increasing duration of exposure to asbestos for all smoking categories except for current smokers of 1-19 cigarettes per day. The statistical power to detect ORs among occupations that were previously reported to be at increased risk of lung cancer but that failed to show an OR of at least 1.5 in the current study was small. The cumulative population attributable risk (PAR) of lung cancer due to occupation was 9.2%. It is concluded that occupational factors play an important part in the development of lung cancer independently of cigarette smoking. Because occupations at high risk of lung cancer were under-represented, the cumulative PAR of the present study is likely to be an underestimate of the true contribution of occupation to risk of lung cancer.

Proportion of lung and bladder cancers in males resulting from occupation: a systematic approach

Studies conducted in several countries that investigated the relationship of occupation and cancer in men were reviewed and compared. Estimates of the proportion of cancers due to occupational exposure that occurred in the general population were analyzed, and sources of variation were explored. A systematic and standardized evaluation of studies on lung and bladder cancer were undertaken, and only investigations that allowed for confounding from tobacco smoking were included. The proportion of lung cancers attributable to occupation ranged between 1 and 5% (when considering only exposure to asbestos) and 40% (in a study with a high proportion of subjects exposed to ionizing radiation); for bladder cancer, estimates were between 0 and 3% in a few studies and between 16 and 24% in several investigations. No similar attempt of systematic comparison was possible for other cancers.

A method for testing the significance of geographical correlations with application to industrial lung cancer in France

This paper discusses some of the problems encountered when testing significance in geographical epidemiology where variables typically exhibit some spatial autocorrelation. A test of partial correlation between spatially autocorrelated variables is presented. It is based on evaluation of an effective sample size which takes account of spatial structure. Performance is assessed by Monte Carlo simulation. The proposed method is used to study male lung cancer rates in specific industries in France.

Proportion of lung cancers in males, due to occupation, in different areas of the USA

Occupational data from 5 case-control studies in the United States involving 2,973 male cases and 3,210 controls were analyzed to estimate the percentage of lung cancer attributable to well-known and suspected lung carcinogens. The studies were conducted in areas heterogeneous in terms of industrial activities. The percentage of lung cancers attributable to occupations entailing potential exposure to well-recognized carcinogens ranged, by study area, from 3 to 17%. The further inclusion of occupational groups with suspect carcinogenic exposures changed these estimates very little. Exclusion of data derived from next-of-kin interviews influenced the estimates of attributable risks, but not in a systematic fashion. The estimates also varied according to ethnic group, smoking status and birth cohort, with higher values in non-whites, non-smokers and among members of more recent birth cohorts. Possible errors in exposure classification, which may make these estimates conservative, are discussed.

Occupation and lung cancer in two industrialized areas of northern Italy

A population-based case-control study on lung cancer was conducted in 2 industrialized areas of northern Italy. Cases (126) were all males who died from lung cancer between 1976 and 1980. Controls (384) were a random sample of males dying from other causes during the same period. Jobs held during working life have been analyzed according to a list of occupations already known to be causally associated with lung cancer (list A) and a list of occupations suspected of being so (list B). Attributable risk percentages in the population for occupations included in either list A or B were about 36% and 12% in the 2 areas. Welders or workers in industries in which welding is common showed elevated odds ratios: 2.9 for welders (95% CI 0.9-9.8); 4.9 (1.1-22.9) for structural metal workers; 11.4 (2.6-49.9) for workers in structural metal production. Other job categories associated with lung cancer included: electricians and workers in electrical machine production, woodworkers (in furniture or cabinet making, but not in carpentry or joinery) and cleaning services. Smoking did not seem to exert a substantial confounding effect. Attributable risk percentages for tobacco smoking were about 78% and 76% in the population of the 2 areas.

Occupation and male lung cancer: a case-control study in northern Sweden

Using a case-control study comprising about 600 men with lung cancer in northern Sweden the potential risk of different occupations and groups of occupations was studied. Longitudinal data concerning occupation, employment, and smoking habits were obtained by questionnaires. Some occupational groups (underground miners, copper smelter workers, electricians, and plumbers) exposed to previously known lung carcinogenic agents such as radon daughters, arsenic, and asbestos, had considerably increased odds ratios, which persisted after adjustment for smoking. A slightly raised odds ratio was observed in a group of blue collar workers potentially exposed to lung carcinogenic agents; this rise in the group as a whole mainly disappeared after adjustment for smoking. Farmers and foresters had strikingly low odds ratios, which could only partly be explained by their more moderate smoking habits. The population aetiological fraction attributable to occupation was estimated as 9%.

Comparison of regulations on occupational carcinogens in several industrialized countries

Regulations controlling the manufacture and use of carcinogens in the industrial setting of various countries are examined. In addition, the occupational exposure limits (OEL) of chemicals known or suspected to be carcinogenic in humans are listed, and criteria for the establishment of OELs are discussed. It is also stressed that control measures should not be confined to a few developed countries, and it is hoped that attracting attention to their unevenness will contribute to the implementation of a more efficient primary prevention of cancer.

Occupational exposure and lung cancer risk

The importance of occupation held longest as a risk factor for lung cancer was examined in a prospective study in Norway of 11,995 men, among whom 125 cases occurred in a follow-up from 1966 through 1978. Based on information about occupation held longest, the respondents were classified into 3 groups according to suspected exposure to respiratory carcinogens at the workplace. After stratification for age, place of residence and cigarette smoking, we found a highly significant relative risk of 2.6 for those judged to have experienced definite exposure versus the group with no workplace exposure. The apparent risk-enhancing effect of occupational exposure was observed for all histologic subtypes. Stratification including a socioeconomic factor score led to a moderate reduction in the relative risk estimate. High risk estimates still obtained, however, for a limited number of occupations, the highest for workers in the mining and quarrying industries. Although the interpretation of the observed effect associated with a crude index of occupational exposure may be difficult, our results suggest that between 13 and 27% of the lung cancer cases observed among Norwegian men in the relevant time period can be attributed to harmful work-place exposure.