Mortality studies of machining fluid exposure in the automobile industry IV; a case-control study of lung cancer

Machining fluids are diverse products that contain numerous additives and contaminants, including polycyclic aromatic hydrocarbons. Studies treating machining fluids as an aggregate exposure have found both positive and negative associations with lung cancer. In this nested case-control study of automotive workers (667 cases and 3,041 matched controls), individual estimates of exposure quantity and duration for specific classes of machining fluids were derived. An inverse dose-response relationship was found between synthetic machining fluids and lung cancer mortality, with an odds ratio of 0.6 (95%Cl = 0.4, 0.8) for the highest level of lifetime exposure. The relationship was strongest for recent exposures. There was little evidence of an association with soluble or straight oil machining fluids. Risks were inconsistently elevated in workers exposed to aluminum. Results from this study provide strong evidence that exposure to machining fluids is not associated with an increased risk of lung cancer mortality in automotive workers. Am. J. Ind. Med. 31:525–533, 1997. © 1997 Wiley-Liss, Inc.     

Mortality studies of machining fluid exposure in the automobile industry V: A case-control study of pancreatic cancer

Results are presented from a case-control study of 97 cases of pancreatic cancer nested in a cohort of workers from three automobile manufacturing plants. Risk was examined for lifetime exposure to straight, soluble, and synthetic metalworking fluids, as used in specific machining or grinding operations, as well as for constituents of the fluids. Pancreatic cancer was associated with exposure to synthetic fluids in grinding operations, with an odds ratio of 3.0 (95% CI: 1.2–7.5) among those with more than 1.4 mg/m³-years of exposure. We were unable to examine synthetic exposure in the absence of grinding because there was virtually no exposure to synthetics in machining operations in this study population. Although a disproportionately high percent of the cases were black, no black workers had any exposure to synthetic fluids, and no other measured exposure was found to be related to risk. Thus, the previously documented excess risk of pancreatic cancer among blacks in this cohort remains unexplained. Am. J. Ind. Med. 32:240-247, 1997. © 1997 Wiley-Liss, Inc.     

Mortality studies of machining fluid exposure in the automobile industry I: A standardized mortality ratio analysis.

Machining fluids are widely used in a variety of common industrial metalworking operations to lubricate and cool both the tool and the working surfaces. Previous studies have suggested elevated respiratory, digestive, and skin cancers in exposed populations. This cohort study was initiated to assess whether long-term exposure to machining fluids in the course of machining, grinding, and other cutting operations is associated with excess cancer mortality. The cohort includes more than 45,000 automobile production workers from 3 plants, almost 1 million years of follow-up, over 10,000 deaths, and an extensive exposure assessment component. Standardized mortality ratios (SMRs) have been estimated for each of the 3 plants, using both U.S. as well as local populations as reference. Relative risks of 1.2-3.1 have been observed for several specific respiratory and digestive cancers of a priori interest, including cancer of the stomach, large intestine, pancreas, lung, and larynx. In addition, elevated risks for leukemia and asthma were noted. Future exposure-response analyses will provide the opportunity to identify relatively modest excesses in cause-specific mortality risk associated with exposure to specific types (straight, soluble, or synthetic), additives, or components of machining fluids.     

Mortality studies of metalworking fluid exposure in the automobile industry: VI. A case-control study of esophageal cancer

Background Results are reported from a nested case-control study of 60 esophageal cancer deaths among 46,384 automobile manufacturing workers potentially exposed to metalworking fluids (MWF) in machining and grinding operations. Methods By using incidence-density sampling, controls were selected with a sampling ratio of 20:1 from among co-workers who remained at risk by the age of death of the case, matched on race, gender, plant, and year of birth. Conditional logistic regression was used to evaluate the risk associated with cumulative exposure (mg/m³-years) to each of three types of metalworking fluid (straight, soluble, and synthetic MWF), as well as with years of exposure to selected components of MWF, including nitrosamines, sulfur, biocides, and several metals. Results Esophageal cancer was found to be significantly associated with exposure to both soluble and synthetic MWF in grinding operations. The odds ratios (ORs) for grinding with soluble MWF were elevated at 2.5 or greater in all categories of cumulative exposure, although the exposure-response trend was statistically significant only when exposure was measured as duration. Those with 12 or more years exposure to soluble MWF in grinding operations experienced a 9.3-fold relative risk of esophageal cancer mortality (95% CI = 2.1–42.1). The OR for ever grinding with synthetic MWF was 4.1 (95% CI = 1.1–15.0). Elevated risk was also associated with two agents found in both synthetic and soluble fluids, nitrosamines, and biocides. For exposure to nitrosamines, the OR was 5.4 (95% CI = 1.5–19.9); for biocides the OR was 3.8 (95% CI = 0.8–18.9). However, because the same workers were exposed to grinding with synthetics, nitrosamines and biocides, it was not possible to separate the specific risks associated with these components. Am. J. Ind. Med. 34:36–48, 1998. © 1998 Wiley-Liss, Inc.     

短链氯化石蜡毒性效应及检测技术研究进展

金属加工液（MWFs)在机械制造行业用量巨大,接触人数众多,其既可简单分为油基切削液和水基切削液2类,也可按性质分为纯矿物油、可溶性油、合成液和半合成液4类。在加工和磨削操作时,由于机械喷溅作用、转动工件力的作用、雾化和蒸发、金属切削工件表面温升高导致燃烧或热解等多种方式,将MWFs油雾直接喷射到操作者手部或面部的暴露皮肤上,或散放至生产环境空气中被操作人员吸入,均可导致职业健康危害。MWFs对皮肤、呼吸系统的健康危害已较为明确,但对其致癌性的问题尚存在争论。为此,本文从MWFs暴露与癌症关系、MWFs种类与癌症关系、MWFs致癌因素等方面对MWFs的致癌性进行了综述,旨在为进一步深入研究MWFs的健康危害提供参考依据。     

Bladder cancer among workers in the textile industry: results of a Spanish case-control study

This paper presents results from a case-control study carried out in the county of Mataro, Spain. The study was designed to investigate the possible causes of an unusually high mortality rate from bladder cancer in Mataro county as compared to Spain as a whole, and this report focuses on occupational exposures. The study is based on 57 cases who were hospitalized for or died from bladder cancer between 1978 and 1981. Two controls per case were matched for sex, age, residence, and date of either hospitalization or death. Information was collected on smoking, coffee drinking, and occupation. Occupational histories were then evaluated and coded blind by a group of occupational health physicians. Analyses were carried out by means of conditional logistic regression. Among a group of common occupational sectors, an increased risk for past employment in the textile industry (OR = 2.2; p = .038) was found. Further analyses indicated that the risk is particularly elevated (OR = 4.41; 95% confidence limits; 1.15-16.84) for subjects who worked in dyeing or printing and who were most probably exposed to azo-dyes. Exposure in the textile industry may be responsible for 16% of the bladder cancers in the Mataro area. A list of dyes commonly used in the Mataro textile industries was compiled and cross-checked with lists of substances tested or evaluated for carcinogenesis.     

Paternal occupation and brain cancer in offspring: a mortality-based case-control study

A mortality-based case-control study of selected risk factors for childhood brain tumors was undertaken. Ohio-born children who died from brain cancer during the 1959-1978 vicennium were compared to control children (of the same age, race, and sex) by using information obtained from the subjects' birth certificates. Differences between the case and the control children with respect to paternal occupation, the focus of the study, were examined. Controlling for the potentially confounding effects of several nonoccupational factors, case fathers were found more likely than control fathers to have been employed (at the time of birth of their children) in agriculture, in metal-related jobs, in structural work jobs in the construction industry, and in electrical assembling, installing, and repairing occupations in the machinery industry. Although the results must be interpreted with caution, the findings lend support to the hypothesis that parental occupation is a potential risk factor for childhood brain tumors.     

Sinonasal cancer and occupation. Results from the reanalysis of twelve case-control studies

A pooled reanalysis of twelve case-control studies on sinonasal cancer and occupation from seven countries was conducted in order to study associations with occupations other than wood- and leather-related occupations. The pooled data set included a total of 930 cases (680 men and 250 women) and 3,136 controls (2,349 men and 787 women). All the studies included a detailed occupational history for cases and controls. Each job was coded using the same classifications for occupation and industry. Two approaches were used in the analysis: systematic analysis of occupations; a priori analysis using a preestablished list of occupations and industries. The results confirmed associations observed in several studies not included in this analysis. For agricultural workers, significant excesses were observed for squamous cell carcinoma among women (OR = 1.69) and men (OR = 3.72 for ten years or more of employment as an orchard worker), and adenocarcinomas among men (OR = 2.98 for ten years or more of employment). Associations with textile occupations were observed for adenocarcinoma among women (OR = 2.60) and squamous cell carcinoma among men (OR = 5.09 for fiber preparers, 3.01 for bleachers). Elevated risks for both histologic types were observed among men employed in food manufacturing (OR = 3.25, adenocarcinoma), or as food preservers (OR = 13.9, squamous cell carcinoma), and among men employed as cooks (OR = 1.99, squamous cell carcinoma). A positive association with squamous cell carcinoma was observed for male transport equipment operators (OR = 1.21), and also with adenocarcinoma for male motor-vehicle drivers (OR = 2.50). A number of other associations were observed in the systematic analysis. Am. J. Ind. Med. 31:153–165, 1997. © 1997, Wiley-Liss Inc.     

Alcohol, smoking, and occupational factors in cancer of the larynx: a case-control study.

A hospital-based case-control study of laryngeal cancer was conducted in Bremen in 1986 and 1987 with 100 prevalent male laryngeal cancer patients and 100 male hospital controls with diseases not considered to be related to smoking, alcohol, or occupational exposures, who were frequency matched by age. The odds ratio for heavy smoking (more than 30 pack-years) reached a value of 3.5 (95% confidence limits (CL) 1.1, 7.9). Ex-smokers showed a significant decrease in risk; this reached the level of those who had never smoked about 15 years after smoking cessation. For daily consumers of alcohol an odds ratio of 3.2 (95% CL 1.4, 7.5) was observed. Among the 17 occupations in which at least ten subjects had worked, excess risks were observed for stock keeping and transportation workers, and for leather and textile workers. The odds ratio was significantly increased for the latter (p less than 0.05). Among all those persons ever employed in a priori defined-risk occupations, an odds ratio of 2.74 (95% CL 1.23, 6.06) was observed. Considering responses to an exposure check-list, no increased risks could be shown for exposure to asbestos, coal tar, or welding fumes. On the other hand, excess risks were observed for exposures to diesel oil, gasoline, and mineral oil, controlling for smoking and alcohol. The findings in occupational and exposure subgroups were based on small numbers of cases and controls and, consequently, were subject to large sampling errors. Many of the results are consistent, however, with occupational risk factors reported from other studies.     

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.     

Mortality studies of machining-fluid exposure in the automobile industry. II. Risks associated with specific fluid types.

Excesses of digestive and respiratory cancers have been reported previously in association with exposure to machining fluids, agents in widespread use as coolants and lubricants in machining operations. Previous studies have had limited power to distinguish the effects of the different types of machining fluids in use. In a cohort of over 30,000 workers employed at two automotive plants in Michigan, mortality patterns were studied in relation to exposure to each of the three major fluid types--straight oils, soluble oils, and synthetic fluids. Standardized mortality ratios were estimated for subgroups of the cohort ever exposed to each of the three fluid types, and Poisson regression analyses were used to assess trends in risk with duration of exposure. The data suggest modest positive associations between exposure to straight oils and rectal, laryngeal, and prostatic cancer and a negative association between soluble and synthetic fluid exposure and lung cancer.     

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.     

Occupational respiratory cancer and exposure to asbestos: A case-control study in a cohort of workers in the electricity and gas industry

Cancers of the pleura, lung, and larynx between 1978 and 1989 among active male workers of Electricité de France-Gaz de France were studied in association with asbestos exposure using a case-control design nested within the cohort of workers of the company. The cohort included about 1,400,000 person-years, corresponding to a mean of 117,000 men per year. Exposure to asbestos and to some potential occupational confounders selected among agents from groups I, IIa, and IIb of the International Agency for Research on Cancer was assessed by a job-exposure matrix specific to the company. During the observation period, 12 cases of pleural cancer, 310 cases of lung cancer, and 116 cases of larynx cancer were registered in the cancer register of the company social security department. Four controls per case, matched for year of birth, were randomly selected among the cohort. Conditional logistic regression was used to estimate the odds ratios. A first analysis was conducted in order to assess the validity of the job-exposure matrix by investigating already known relationships between asbestos exposure and asbestosis. For asbestosis, a strong exposure-response relation was found with an odds ratio (OR) of 57.4 [95% confidence interval (CI): 17.0–194.0] in the highest exposure group. There was an elevated risk of pleural cancer (OR, 4.8, CI, 1.2–19.8). For lung cancer, significant ORs of 2.0 (CI, 1.3–3.2) and 1.9 (CI, 1.2–3.0) were found among the two highest cumulative exposure groups; adjustement for confounders slightly decreased the ORs. Squamous cell neoplasm of the lung was associated with asbestos exposure. The association between larynx cancer and asbestos exposure showed a tendency towards a nonsignificant increase in ORs in the highest cumulative exposure categories; this tendency disappeared when adjusting for occupational confounders. This study showed that occupational exposure to asbestos could increase the risk of pleural and lung cancer in a sector in which exposure levels are not considered to be high compared with other industrial settings.     

Lung cancer mortality in stainless steel and mild steel welders: A nested case-referent study

The association between welding and lung cancer has been studied in a nested case-referent study within a cohort of 8,372 metal workers. Lifetime exposure data on welding and other occupational exposures, as well as alcohol and smoking habits, were obtained by interviews of spouses and colleagues. Analysis was based on 439 deceased referents and 94 deceased cases. There was 70% excess of lung cancer associated with “welding exposure ever” (OR ± 95% C.I.: 1.68, 1.02–2.78). Overall OR “mild steel (MS) welding ever” was 1.64, 0.99-2.72. The risk estimates for welding exposures showed an increasing tendency up to 15 years of exposure. The pattern of stainless steel (SS) welding resembles that of mild steel with an estimated OR of 1.65, 0.88–3.0. The general conclusion is that MS welding as well as SS welding seems to be associated with an increased risk of lung cancer. Further followup of the cohort will enhance precision of the estimates. © 1996 Wiley-Liss, Inc.     

Practical and analytical aspects of using friend controls in case-control studies: experience from a case-control study of childhood cancer

We report empirical data on the use of friend controls, specifically response rates, case-control concordance and analytical approaches. The data derive from a North American multi-institutional study of childhood cancer that was conducted in 2002-07 and that focused on paternal exposures. Case parents nominated friends as potential controls; up to three controls participated per case. For 137 (69%) of the 199 case families, at least one control parent participated. Of 374 potential controls contacted, 247 (66%) participated. Case fathers with controls were markedly more likely to be non-Hispanic White, college graduates and non-smokers compared with case fathers without controls. Odds ratios adjusted for demographic characteristics were generally similar but occasionally differed between analyses that included only members of matched sets and those that included all participants, i.e., controls and cases with and without controls. For demographic characteristics, simulations demonstrated that the observed concordance of cases and controls within matched sets exceeded that expected under random ascertainment, indicating probable overmatching. However, the observed concordance of smoking and other exposures was similar to the expectation under random ascertainment, suggesting little overmatching on exposures. Although not ideal, friend controls were convenient, had a reasonably high response rate and provided controls closely matched on race/ethnicity, education and age.     

Use of organic solvents and potential worker exposure in the motor vehicle manufacturing industry

This survey was designed to assist with planning epidemiologic studies of the effects of solvent exposure among motor vehicle manufacturing workers. The objectives were to identify subgroups of workers with solvent exposure, and to evaluate the availability of data for a job-exposure matrix (JEM). Of 65 plants selected, 31 (48%) participated. Participant plants represent all production activities initially included in the survey, and employ 97,655 hourly workers. About 14% of these workers use organic solvents (direct exposure), and 19% work in the proximity of solvent-using operations (indirect exposure). However, only 3% have direct exposure, and 6% have indirect exposure to large-volume (≥ 100 gallons/month)/high-frequency (hourly)-use solvents. The highest solvent exposure prevalence occurs in plants manufacturing engines and power train components and in metal degreasing/cleaning and painting tasks, and entails exposure to petroleum fractions, aromatic hydrocarbons, alcohols, and ketones. A JEM can be developed using plant records on job titles, work histories, production scheduling, and plant engineering, and using the corporate computerized personnel and industrial hygiene databases. However, information on solvent use and on exposure is adequate only for recent time periods. © 1993 Wiley-Liss, Inc.     

A pilot study of take-home lead exposure in new jersey

Studies in various industries have found an association between worker exposure to lead and elevated blood lead levels in workers' children, but the magnitude of this problem is unknown. In an effort to characterize this problem further, a pilot study was undertaken to obtain blood lead levels of children of lead-exposed workers with elevated blood lead levels who had been reported by laboratories to the New Jersey Department of Health. Fifteen workers' families participated in this study, including 28 children. Thirty-two percent of the children were found to have blood lead levels ≧ 10 μg/dl, the level of concern set by the Centers for Disease Control and Prevention for medical monitoring. This finding is in contrast to population-based data collected from the Third National Health and Nutrition Survey, where the overall prevalence of blood lead levels ≧ 10 μg/dl was only 4.5%.     

Occupational exposure to machining fluids and laryngeal cancer risk: Contrasting results using two separate control groups

This death certificate-based case-control study linked Connecticut Tumor Registry and Connecticut Division of Vital Statistics death data to determine whether machining fluid exposure is associated with laryngeal cancer risk. Laryngeal cancer cases were compared with oral cancer controls and general population controls. Level of exposure to machining fluids was imputed from the usual occupation and industry on the death certificate. Because exposure was infrequent among females, analysis was limited to males. When cases were compared to oral cancer controls, high exposure to machining fluids was associated with laryngeal cancer (odds ratio = 1.48; 95% confidence interval = 1.01–2.16), with a p–value for trend of 0.08. When cases were compared to population controls, no association between machining fluid exposure and laryngeal cancer was observed. A possible reason for the contrasting results, other than chance, is that exposure data quality for the cases and oral cancer controls may have differed from that of the population controls. Am. J. Ind. Med. 31:166–171, 1997. © 1997 Wiley-Liss, Inc.     

A strategy to reduce healthy worker effect in a cross-sectional study of asthma and metalworking fluids

This report describes the reanalysis of a cross-sectional study of asthma in a large cohort of autoworkers with exposure to metalworking fluids (MWF). There is strong evidence from case reports, clinical studies, and medical surveillance data that exposure to MWF can cause asthma, yet no association was found in the original analysis. The central hypothesis of the reanalysis was that the absence of an association between asthma and MWF exposure was the result of bias caused by the self-selection of asthmatics out of exposed jobs. We addressed the potential job transfer bias by redefining exposure and disease status at the time of asthma onset, rather than at the time of the health survey. This permitted us to treat the cross-sectional study as if it were a historical cohort study, despite the fact that the population was a biased sample of the full cohort. This approach resulted in a significantly elevated incidence rate ratio of 3.2 (95% CI: 1.2–8.3) for synthetic MWF estimated in a Cox proportional hazards model. Although the cross-sectional design makes it impossible to document or control for differential selection out of the workforce, the approach described here provides a strategy for reducing the healthy-worker effect due to job transfer bias in cross-sectional studies. Am. J. Ind. Med. 31:671–677, 1997. © 1997 Wiley-Liss, Inc.     

Evaluation of risks for non-Hodgkin's Lymphoma by occupation and industry exposures from a case-control study

The etiology of non-Hodgkin's lymphoma (NHL) is not well understood. To develop hypotheses on causes of this tumor, data from a population-based case-control interview study of 1,867 white men (622 cases and 1,245 controls) in Iowa and Minnesota conducted during 1980–1983 were examined. Subjects, or their next of kin, were interviewed to obtain information on agricultural exposures, work history, medical conditions, and family history. This analysis focuses on risks of NHL by occupation, by industry, and by selected exposures. Although many comparisons were made, few significant associations were observed. Small numbers and limitations in exposure assessment, however, would tend to reduce opportunities to detect associations. The strongest finding was with various occupations that work in metals and metal products. The analysis by exposure estimates also uncovered a significant association with metals, but risks did not increase with estimated intensity of exposure. Slightly elevated risks were also noted among persons employed as painters and construction workers, agricultural and forestry workers, printers and typesetters, funeral directors and embalmers, and dry cleaners. Although the overall risks for benzene and other solvents were small, they increased slightly with level of assigned exposure. Although some associations may be due to chance, several of these occupations and industries have been linked to lymphoma in other investigations and deserve further attention. © 1993 Wiley-Liss, Inc.