A case-control study of the relationship between the risk of colon cancer in men and exposures to occupational agents

BACKGROUND: We conducted a population-based case-control study in Montreal, Canada, to explore associations between hundreds of occupational circumstances and several cancer sites, including colon. METHODS: We interviewed 497 male patients with a pathologically confirmed diagnosis of colon cancer, 1514 controls with cancers at other sites, and 533 population-based controls. Detailed job histories and relevant potential confounding variables were obtained, and the job histories were translated by a team of chemists and industrial hygienists into a history of occupational exposures. RESULTS: We found that there was reasonable evidence of associations for men employed in nine industry groups (adjusted odds ranging from 1.1 to 1.6 per a 10-year increase in duration of employment), and in 12 job groups (OR varying from 1.1 to 1.7). In addition, we found evidence of increased risks by increasing level of exposures to 21 occupational agents, including polystyrene (OR for "substantial" exposure (OR(subst)) = 10.7), polyurethanes (OR(subst) = 8.4), coke dust (OR(subst) = 5.6), mineral oils (OR(subst) = 3.3), polyacrylates (OR(subst) = 2.8), cellulose nitrate (OR(subst) = 2.6), alkyds (OR(subst) = 2.5), inorganic insulation dust (OR(subst) = 2.3), plastic dusts (OR(subst) = 2.3), asbestos (OR(subst) = 2.1), mineral wool fibers (OR(subst) = 2.1), glass fibers (OR(subst) = 2.0), iron oxides (OR(subst) = 1.9), aliphatic ketones (OR(subst) = 1.9), benzene (OR(subst) = 1.9), xylene (OR(subst) = 1.9), inorganic acid solutions (OR(subst) = 1.8), waxes, polishes (OR(subst) = 1.8), mononuclear aromatic hydrocarbons (OR(subst) = 1.6), toluene (OR(subst) = 1.6), and diesel engine emissions (OR(subst) = 1.5). Not all of these effects are independent because some exposures occurred contemporaneously with others or because they referred to a group of substances. CONCLUSIONS: We have uncovered a number of occupational associations with colon cancer. For most of these agents, there are no published data to support or refute our observations. As there are few accepted risk factors for colon cancer, we suggest that new occupational and toxicologic studies be undertaken focusing on the more prevalent substances reported herein.     

Contribution of biological markers to occupational health.

Occupational diseases are now being assessed at the cellular and molecular levels; this presents new opportunities for prevention and control [Calleman et al., 1978; Ong et al., 1987; Stejskal et al., 1989; Welch and Cullen, 1988; Garry et al., 1989]. The key to these opportunities is the ability to detect biological markers that reflect exposure, response, and susceptibility. Biological markers are not new, however. Biological markers such as blood lead, urinary phenol levels in benzene exposure, and liver function assays have long been used in occupational and public health research and practice. What distinguishes the current generation of markers from previous markers is a greater degree of analytical sensitivity and the ability to describe events that occur earlier in the progression between exposure and clinical disease. There are now new domains of response that were not known to exist 20 years ago. Accompanying this sensitivity is the increased requirement to consider the numerous factors that can influence the appearance of biological markers. It has been observed that all workers with similar exposures do not develop disease or markers indicative of exposure or disease. Various acquired and hereditary host factors are responsible for this variation in responses. The role of assessing the nature and degree of variation between individuals is of paramount importance. Finally, the use of biological markers in occupational health research and practice also brings new ethical and legal considerations into high profile. This paper presents my personal opinions on how biological markers can contribute to occupational health efforts and the new requirements that they bring to the field. As with any technological change, the more we can anticipate the impact, the better our ability to adjust.     

Estimates of the extent of morbidity and mortality due to occupational diseases in Canada

Objective: To estimate the extent of occupational disease morbidity and mortality in Canada by comparing and contrasting four different data sources. Data Sources: 1) Canadian National Workers' Compensation Boards Statistics, 2) U.S. Bureau of Labor Statistics adjusted to Canadian Workforce, 3) California Physician's First Reports adjusted to the Canadian Workforce, and 4) proportionate model of overall disease incidence obtained through literature review. Main Findings: Each data source was limited in its ability to provide a true estimate of the extent of morbidity and mortality due to occupational disease in Canada. Collectively, an estimate of between 77,900 and 112,000 new cases of occupational diseases and 2,381 to 6,010 occupational disease deaths were obtained. Conclusions: Occupational diseases are a significant and underestimated cause of morbidity and mortality in Canada. © 1994 Wiley-Liss, Inc.     

Social disparities in the burden of occupational exposures: results of a cross-sectional study

BACKGROUND: Most occupational studies evaluate a single exposure in relation to a particular disease. However, workers typically experience multiple exposures simultaneously. There is also increasing evidence of disparities in health by sociodemographic characteristics, mostly related to social position such as gender, race/ethnicity, immigration status, income, and education. Little information exists on the worker experience of multiple occupational exposures as they vary among social groups. The objectives of this article were to: assess the burden of exposures reported within 1 year by a socially diverse population working in a range of industries; and evaluate whether sociodemographic characteristics affected the patterns of these exposures. METHODS: Study participants were from 14 unionized worksites in meat processing, electrical lighting manufacturing, retail grocery stores, and school bus driving. A cross-sectional study design used a self-administered, computer-assisted questionnaire (English and Spanish) to assess sociodemographic characteristics and nine workplace exposures, within the past year. An interviewer-administered job history also was collected. RESULTS: Twelve hundred eighty-two workers (72%) completed the survey: 36% women, 23% Latino, 39% black, 24% white, and 48% born outside the US. The prevalence of high exposures ranged from 21% (chemicals) to 39% (neck strain). Forty-six percent reported three or more high exposures. Exposure reporting varied among sociodemographic groups. Some of the disparities were explained by the jobs held by different groups, but after statistically controlling for job, many disparities remained. CONCLUSIONS: Sociodemographic characteristics should be considered when conducting exposure assessments using questionnaires. More research is needed to understand how social characteristics may influence exposures.     

Case-control study of exposure to carbon black in the occupational setting and risk of lung cancer

Although it has been hypothesized that carbon black exposure may carry an excess risk of lung cancer, evidence to date is insufficient to assess the hypothesis properly. The relationship between workplace exposure to carbon black and lung cancer risk was examined in a population-based case-control study carried out in Montreal, Canada. Detailed job histories were elicited from 857 incident cases with histologically confirmed lung cancer as well as from 1,360 cancer controls and 533 population controls. Job histories were evaluated by a team of hygienists and chemists for evidence of exposure to a host of occupational substances, including carbon black. Logistic regression analyses adjusting for smoking and other nonoccupational and occupational potential confounders suggested no significant increase in risk with relatively low exposure to carbon black. Some increase in risk for all lung cancers was apparent with relatively high exposure using cancer controls (OR = 2.17; 95% CI = 0.95–4.91) and population controls (OR = 1.52; 95% CI = 0.58–3.97). Individuals with relatively high exposure had a significantly greater risk of oat-cell carcinoma using either control series (OR = 5.05; 95% CI = 1.72–14.87 using cancer controls and OR = 4.82; 95% CI = 1.36–17.02 using population controls). These results provide some evidence for an association between exposure to carbon black and lung cancer. © 1996 Wiley-Liss, Inc.     

Characterization of the airborne concentrations of lead in U.S. industry

Occupational exposure to lead represents a continuing problem of significant magnitude in the United States. To characterize the problem for surveillance purposes, an analysis of the airborne concentrations of lead identified in OSHA compliance inspections was conducted for the years 1979 to 1985. The five specific objectives of the study were: 1) to examine the distribution of air lead concentration in industrial environments; 2) to determine the secular trends in air lead concentrations for high lead industries; 3) to assess which job titles had excessive airborne lead concentrations; 4) to evaluate whether there was a relationship between lead overexposure and company size, unionization, or type of inspection; and 5) to investigate the prevalence of respirator violations for lead. Fifty-two industries were identified which had more than 1/3 of their inspection medians greater than the permissible exposure limit. These included primary and secondary lead smelting, battery manufacture, pigment manufacture, brass/bronze foundries, as well as 46 other industries. There has been little if any improvement in the prevalence and severity of airborne lead concentrations for the high lead industries, battery manufacture, secondary smelting, pigment manufacture, and brass/bronze foundries. Specific high exposure job titles are identified for certain high lead industries. The job title of painting stands out as an especially problematical job title across a number of industries. The prevalence of respirator violations is approximately 20% of all lead inspections.     

Pleural malignant mesothelioma in Tuscany, Italy (1970-1988): II. Identification of occupational exposure to asbestos.

Following the finding of an unexpected cluster of mesotheliomas in textile workers, a surveillance system of malignant mesotheliomas was implemented in the region of Tuscany, Italy. This article reports on the investigation of 124 cases of mesothelioma diagnosed and reviewed by the Institutes of Morbid Anatomy and Histopathology at the Universities of Florence, Pisa, and Siena between 1970 and 1988. A complete occupational and asbestos exposure history was assessed through a semi-structured questionnaire directly administered to resident cases of Tuscany or, if deceased, to their closest living relatives, for a total of 100 interviews. The hypothesis of past occupational asbestos exposure was verified and documented. Seventy-two cases have been classified as occupationally exposed to asbestos; four were classified in the category of "possible domestic" exposure to asbestos. For two others, the role of other risk factors was stressed, and for 22 cases, either no asbestos exposure was found or the available data were not adequate to define it. The present study allowed identification of some unknown or scarcely known occupational asbestos exposures in the study area.     

Congenital defects of the central nervous system and occupational factors during pregnancy. A case-referent study

The possible impact of occupational factors on the furtherance of congenital defects has been under study at our department for the past four years, and it has assumed a special interest because of the importance to understand the etiology of these disorders and a good possibility for prevention by elimination of the causative factor from the work environment. In connection with a register based case-referent study utilizing supplementary information, acquired by a single interviewer, we analyzed various occupational factors related to pregnancy. We found that organic solvent exposure and exposure to various dusts during the pregnant period were more common among the case mothers than among their matched referents. These findings may offer further rough guidance in the quest for the identification of possibly embryotoxic agents that may occur in occupational life.     

Disease clusters in occupational medicine: a protocol for their investigation in the workplace.

Disease clusters have been an important source of epidemiologic and medical information in the history of occupational medicine. Many accepted disease-exposure linkages were first observed and investigated as disease clusters in the workplace setting. Recent interest in disease cluster methodology has focused on traditional environmental settings. There has been very little work on a similar methodology for the investigation of disease clusters in the workplace, despite the many advantages of workplace cluster investigations for recognizing new etiologic associations. In this paper, a protocol is proposed and discussed which can be implemented in both acute and chronic disease cluster outbreaks in the workplace, where no obvious previously recognized cause is identified. A standardized approach to occupational disease cluster investigation will lead to increased efficiency, decreased social-political tensions, and a greater yield of scientific information.     

广西2002年职业病发病报告与分析

目的 了解广西2002年职业病发病现状。方法 对广西2002年职业病构成、行业分布、接触职业有害因素工人健康监护情况进行分析。结果 广西2002年度报告职业病159例。其中，尘肺新发病人66例，占报告职业病的41．51％，居各种职业病之首；急性职业中毒56人，占35．22%，发病率仅次于尘肺；广西尘肺病主要分布在煤炭、冶金及有色金属、水电工程和建筑材料行业；急性职业中毒主要分布在化学品生产及运输、食品加工、农药生产和销售部门的个体承包、私营企业；由于职业健康检查率低，78．92%的接触有害因素作业工人没有得到职业健康检查，可能尚有患职业病的病人没有被发现。结论 尘肺病和急性职业中毒是广西当前主要的职业病，应着重对这两类职业病发病的重点行业进行职业病危害防治；广西职业病发病实际情况严峻，有关部门对此应有充分认识，采取有效措施，彻实做好职业病防治工作。