Determining the hazards of work place chemicals.
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Air Pollutants, Occupational↗
Biomedical subjects
P Boffetta
Publications and source records attributed to P Boffetta.
Carcinogenicity of mercury and mercury compounds.
Mercury and mercury compounds are widely used in modern society, but only sparse data are available on their carcinogenicity. Methylmercury chloride causes kidney tumors in male mice. Mercury chloride has shown some carcinogenic activity in male rats, but the evidence for female rats and male mice is equivocal. Other mercury compounds and metallic mercury have not been tested adequately in experimental animals. Epidemiologic data are available for chloralkali workers, dentists and dental nurses, and nuclear weapons workers, three groups occupationally exposed to low levels of mercury and its compounds, but those highly exposed in the past, such as miners, or populations which have suffered massive environmental exposure have not been adequately studied. However, the sparse epidemiologic data point toward the possibility of a risk of lung, kidney, and central nervous system tumors. Better data are needed on the carcinogenicity of mercury and mercury compounds in humans and experimental animals.
Animals↗
Carcinogenicity of trace elements with reference to evaluations made by the International Agency for Research on Cancer.
The monograph program of the International Agency for Research of on Cancer has evaluated many trace elements for their carcinogenicity to humans. Five groups of compounds were considered human carcinogens: arsenic and arsenic compounds, beryllium and beryllium compounds, cadmium and cadmium compounds, hexavalent chromium compounds, and nickel compounds. Antimony trioxide, cobalt and cobalt compounds, lead and inorganic lead compounds, methylmercury compounds, and metallic nickel were considered possibly carcinogenic to humans. Antimony trisulfide, trivalent chromium compounds, metallic chromium, ferric oxide, organolead compounds, metallic mercury, inorganic mercury compounds, selenium and selenium compounds, and titanium dioxide were not classifiable. Trace elements studied to a limited extent include copper, manganese, tin, vanadium, and zinc. Among the problems are the lack of relevant data, the definition of active species, the extrapolation of the results of experimental studies to humans, the methodological problems of epidemiologic studies, and the possible anticarcinogenic activity of some trace elements.
Humans↗
Occupational cancer in developing and newly industrialized countries.
Cancer is a worldwide public health problem, accounting for an increasing proportion of all deaths. It is the second leading cause of death in most of the industrialised world, and developing countries appear to be launched on a cancer epidemic, similar to that in industrialised countries. In developing countries, most cancer deaths are due to tumours of the stomach, oesophagus, lung, liver and uterine cervix; occupational cancers account for an undetermined number of these cases. Occupationally associated neoplasms may either be related directly to specific exposures within a workplace, e.g., bladder cancer in benzidine-exposed workers, or reflect indirect factors, including socioeconomic status and conditions of life. Asbestos-induced pneumoconiosis is recognised as an occupational disease in many developing countries, whereas asbestos-related malignancies draw less attention. The rising prevalence of cigarette smoking in these countries greatly magnifies the effect of asbestos in inducing lung cancer. Transplantation of industries from developed to developing countries is often accompanied by a reduction in the standard of working conditions. The rising unemployment in developing countries is unlikely to incite workers to claim better conditions.
Animals↗
Carcinogenic effect of tobacco smoking and alcohol drinking on anatomic sites of the oral cavity and oropharynx.
A series of 359 male patients with 424 cancer lesions of the oral cavity and oropharynx identified at a US Department of Veterans Affairs Medical Center were divided according to site of origin of the lesion and compared with 2,280 controls from the same hospital with respect to exposure to tobacco smoking and alcohol drinking. Sites of origin were: floor of the mouth (153), oral tongue (50), anterior tonsillar pillar (49), soft palate (44), lingual aspect of retromolar trigone (11), alveolar ridge (5), buccal mucosa (4), and hard palate (2). Forty-one patients had cancers in multiple sites. Tobacco smoking was more strongly associated with soft-palate lesions than with lesions in more anterior sites. Patients with cancer of floor of the mouth and oral tongue had higher odds ratios for alcohol drinking than subjects with cancers of other sites. This study supports the hypothesis of the carcinogenic effect of tobacco smoke and alcoholic beverages on the oral mucosa through direct contact.
Adult↗
Risk factors for fatal colon cancer in a large prospective study.
BACKGROUND: Diet, physical activity, obesity, aspirin use, and family history may all modify the risk of colon cancer, but few epidemiologic studies are large enough to examine these factors simultaneously. PURPOSE: We prospectively assessed the relationship of diet and other factors to risk of fatal colon cancer. METHODS: Using data from Cancer Prevention Study II--an ongoing prospective mortality study--we studied 764,343 adults who, in 1982, completed a questionnaire on diet and other risk factors and did not report cancer or other major illness. We assessed mortality through August 1988 and identified 1150 deaths from colon cancer (611 men and 539 women). Multivariate analyses were used to compare these case patients with 5746 matched control subjects drawn from the cohort. RESULTS: Risk of fatal colon cancer decreased with more frequent consumption of vegetables and high-fiber grains (P for trend = .031 in men and .0012 in women). The relative risk (RR) for the highest versus lowest quintile of vegetable intake was 0.76 in men (95% confidence interval [CI] = 0.57-1.02) and 0.62 in women (95% CI = 0.45-0.86). Dietary consumption of vegetables and grains and regular use of aspirin were the only factors having an independent and statistically significant association with fatal colon cancer. Participants who consumed the least vegetables and grains and no aspirin had a higher risk compared with those who consumed the most vegetables and used aspirin 16 or more times per month. For men in the former category, the RR was 2.4 (95% CI = 1.1-5.3); for women, it was 2.9 (95% CI = 1.3-6.7). Weaker associations were seen for physical inactivity, obesity, total dietary fat, and family history. No associations were seen with consumption of red meat or total or saturated fat in either sex, but this finding must be interpreted cautiously. CONCLUSIONS: These findings support recommendations that increased consumption of vegetables and grains may reduce the risk of fatal colon cancer. Regular use of low doses of aspirin may prove to be an important supplemental measure.
Adult↗
Soft-tissue sarcoma.
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Agricultural Workers' Diseases↗
Comparison of questionnaire-derived and tumour registry-derived smoking histories.
Information on cigarette smoking, an exposure of great epidemiological interest, is occasionally obtained from tumour registry data. We compared smoking histories from a hospital tumour registry with those from a questionnaire administered to 94 lung cancer patients. Reliability of tumour registry data was good for classifying individuals as ever-smokers and non-smokers (sensitivity 0.96, specificity 0.86). There was higher discrepancy in classifying smokers as current or former smokers. Current smokers had lower reliability for amount of smoking than former smokers, whereas both groups had high reliability for duration of smoking. These results suggest that tumour registry derived data on smoking must be used with caution.
Age Factors↗
Lung cancer mortality among workers in the European production of man-made mineral fibers--a Poisson regression analysis.
One hundred and eighty-one lung cancer deaths among workers during 301,085 person-years in European man-made mineral fiber production between 1930-1955 and 1982 were analyzed according to Poisson regression models including age, calendar period, country, and exposure variables. Time since first employment was the variable most strongly associated with lung cancer risk in both the rock-slag wool and glass wool subcohorts. Workers in the early technological phase were at higher risk than those in other categories, particularly in rock-slag wool production. No clear trend with duration of employment was suggested. No major changes occurred in the interpretation of the results when workers with less than one year of employment or less than 20 years since first exposure were excluded. The original results, based on analyses for standardized mortality ratios, were confirmed, and workers with a short duration of employment or a short time since first employment did not need to be excluded from the analysis.
Air Pollutants, Occupational↗
Methodological aspects of the epidemiological association between cadmium and cancer in humans.
The main epidemiological evidence of an association between cadmium exposure and human cancer comes from studies on occupational groups such as smelter and nickel-cadmium battery workers. Lung and prostate are the sites more frequently reported to be at increased risk of cancer, but the various epidemiological studies do not enable any definite conclusion to be reached. Methodological problems in the interpretation of these studies include: (i) the assessment of exposure to cadmium; (ii) the dose-response relationship between indicators of cadmium exposure and cancer risk; (iii) concomitant exposure to occupational carcinogens, mainly nickel and arsenic; (iv) confounding by non-occupational risk factors, such as smoking and diet; and (v) interaction between cadmium and other exposures. The confounding effect of smoking and diet is particularly interesting since they may act both as additional uncontrolled sources of cadmium and as independent cancer risk factors.
Cadmium↗
Relationship between histologic features, DNA flow cytometry, and clinical behavior of squamous cell carcinomas of the larynx.
Flow cytometric analysis of DNA content was done on 133 primary squamous cell carcinomas of the larynx. Overall, 76 tumors (57.1%) were not diploid (aneuploid or tetraploid). The DNA index (DI) was calculated and grouped into three levels. Fifty-seven cases had a DI in a range of 1.85 to 2.15 (44 diploid and 13 tetraploid). The cases were grouped in relation to ploidy, proliferative index, and the tumor-node-metastasis (TNM) system. Every group was analyzed with respect to survival rate. Ploidy was related to histocytologic grade. In well-differentiated tumors (G1) survival rates at 48 months were 41.7% in diploid cases and 27.7% in nondiploid ones (relative risk [RR], 2.01; 95% confidence interval [CI], 0.89, 4.52). In NO cases that underwent surgery, survival rates at 48 months were, respectively, 81.8% and 49.2% (RR, 5.07; 95% CI, 0.76, 33.93). These results suggest that ploidy may be a new independent parameter of prognosis in squamous cell carcinoma of the larynx. This is useful in clinical practice because it allows the clinician to recognize those cases with poorer prognosis among the early tumors at a stage where other prognostic parameters are not yet available.
Aneuploidy↗
Cancer risks related to electricity production.
The International Agency for Research on Cancer has previously evaluated the cancer risks associated with fossil fuel-based industrial processes such as coal gastification and coke production, substances and mixtures such as coal tars, coal tar pitch and mineral oils, and a number of substances emitted from fossil-fuelled plants such as benzo[a]pyrene and other polycyclic aromatic hydrocarbons, arsenic, beryllium, cadmium, chromium, nickel, lead and formaldehyde. Based on these evaluations and other evidence from the literature, the carcinogenic risks to the general population and occupational groups from the fossil fuel cycle, the nuclear fuel cycle and renewable cycles are reviewed. Cancer risks from waste disposal, accidents and misuses, and electricity distribution are also considered. No cycle appears to be totally free from cancer risk, but the quantification of the effects of such exposures (in particular of those involving potential exposure to large amounts of carcinogens, such as coal, oil and nuclear) requires the application of methods which are subject to considerable margins of error. Uncertainties due to inadequate data and unconfirmed assumptions are discussed. Cancer risks related to the operation of renewable energy sources are negligible, although there may be some risks from construction of such installations. The elements of knowledge at our disposal do not encourage any attempt toward a quantitative comparative risk assessment. However, even in the absence of an accurate quantification of risk, qualitative indication of carcinogenic hazards should lead to preventive measures.
Accidents, Occupational↗
A cohort mortality study and a case-control study of workers potentially exposed to styrene in the reinforced plastics and composites industry.
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Case-Control Studies↗
Occupation and cancer of the oral cavity or oropharynx in Turin, Italy.
In a population-based case-referent study, the occupational experience of 86 men with oral or oropharyngeal cancer and 373 referents was analyzed with respect to employment in 41 occupations and 40 industries, as well as to exposure to 16 chemicals, as estimated via a job-exposure matrix. Among the occupations and industries at higher risk were machinery operator (odds ratio [OR] 2.0; 95% confidence interval [95% CI] 1.0-4.0), plumber (OR 5.0, 95% CI 1.2-21.5), building industry (OR 2.5; 95% CI 1.3-4.5), textile industry (OR 2.5; 95% CI 0.6-4.6), and electricity production (OR 2.8; 95% CI 0.7-12.1). All the OR estimates were adjusted for age, education, area of birth, tobacco smoking, and alcohol consumption. An association between formaldehyde exposure and oral cancer was suggested (OR for any exposure 1.6, 95% CI 0.9-2.8; OR for probable or definite exposure 1.8, 95% CI 0.6-5.5). No other chemical included in the matrix showed any risk pattern. The evidence of an association between formaldehyde exposure and oral or oropharyngeal cancer is strengthened by the results of this study.
Case-Control Studies↗
Topographic classification, clinical characteristics, and diagnostic delay of cancer of the larynx/hypopharynx in Torino, Italy.
The case series of a population-based case-control study of laryngeal and hypopharyngeal cancers in Torino, Italy, included 281 men with clinical and anamnestic data. Two hundred fifteen, 28, and 38 cancers originated from the endolarynx, epilarynx, and hypopharynx, respectively. Regions invaded by the tumor were divided into 26 subsites. A classification based on the number of invaded subsites was proposed, which agreed well with the T classification of the TNM system. Cancers originating from the hypopharynx invaded more subsites than cancers from the endolarynx, and among the latter, supraglottic were more invasive than glottic lesions. The number of invaded subsites was strongly associated with nodal involvement. Among symptoms at onset of disease and at diagnosis, patients with endolaryngeal lesions reported dysphonia and dyspnea more frequently, and patients with lesions from other regions had a higher prevalence of dysphagia, odynophagia, otalgia, and adenopathia. Clinical and epidemiologic results of this study suggest considering the endolarynx, epilarynx, and hypopharynx as separate anatomic entities. Diagnostic delay was not associated with tumor size and showed a negative trend with involvement of cervical lymph nodes, suggesting that stage at diagnosis is due to intrinsic differences in tumor aggressiveness.
Carcinoma, Squamous Cell↗
Association between smoking and leukemia in two American Cancer Society prospective studies.
The association between smoking and leukemia in men and women was analyzed from the data of two prospective studies. Myeloid leukemia was positively associated with smoking in men in both studies (standardized mortality ratios [SMR], 2.44 and 1.32; P less than 0.05), but not with smoking in women. Lymphatic leukemia showed no elevation in risk in men and women in both studies. Animal studies suggest a real biologic difference in leukemogenic effect between the sexes, but further analyses are needed to characterize the smoking effect of leukemia in women.
Adult↗
Case-control study on occupational exposure to diesel exhaust and lung cancer risk.
The association between lung cancer and occupations with probable exposure to diesel exhaust (DE) was studied among 2,584 cases and 5,099 hospital controls. The crude odds ratio (OR) for probable exposure was 1.31 (95% confidence interval [CI] 1.09-1.57), but adjustment for smoking and other confounders reduced the estimate to 0.95 (95% CI = 0.78-1.16). Similar results were observed for truck drivers, the only occupational category large enough for separate analysis. Data on self-reported exposure for 477 cases and 946 controls revealed a crude OR of 1.45 (95% CI = 0.93-2.27), which was reduced to 1.21 (95% CI = 0.78-2.02) after controlling for smoking and other confounders. The present results and a review of the literature do not definitively support an etiologic association between DE exposure and elevated lung cancer risk.
Adult↗
Leisure time physical activity in a hospital-based population.
The epidemiology of self-reported leisure time physical activity (LTPA) has been studied among 3381 men and 1664 women enrolled in a hospital-based case-control study. 51% of men and 36% of women reported LTPAs during a lifetime, and 23% of men and 22% of women reported LTPAs after 44 years of age. Brisk walking, swimming, cycling and tennis accounted for the majority of LTPAs after 44 years of age. Only 13% of men and 9% of women reported LTPA practice for more than 20 years and more than 3 hours/week; and 0.6% of men and 0.1% of women reported running or jogging for the same duration. LTPA practice was related to age, education, smoking status, and body mass index. Specifically, ex-smokers reported more frequently LTPA practice than current smokers. Despite the effort to identify aerobic exercise, results from the present analysis suggest that LTPA practice might be over-reported, as a result of a "wish" bias. Problems arising from the use of data on self-reported LTPA practice are discussed in detail.
Adolescent↗