Does occupational exposure to PAHs,diesel and aromatic amines interact with smoking and metabolic genetic polymorphisms to increase the risk on bladder cancer?; The Belgian case control study on bladder cancer risk

To investigate the association between occupational exposure to polycyclic aromatic hydrocarbons, aromatic amines and diesel and bladder cancer risk and the modification by smoking and metabolic polymorphisms, have we recruited 200 cases and 385 population controls. The adjusted OR of bladder cancer was 5.75 (95%CI 2.09-15.83) comparing the highest tertile of the cumulative probability of occupational exposure to aromatic amines with no occupational exposure. A possible interaction between occupational exposures to aromatic amines and smoking was found. The increased ORs of GSTM1, GSTT1, NAT2 and SULT1A1 among those ever occupational exposed was explored by estimating the false-positive report probability. We confirm that occupational exposure to aromatic amines is associated with an increase in bladder cancer risk.     

Occupation and Bladder Cancer Risk in a Population-based Case-control Study in New Hampshire

OBJECTIVE: To identify occupations with excess bladder cancer risk in New Hampshire, where bladder cancer mortality rates have been elevated for decades. METHODS: Lifetime occupational histories were obtained from interviews with 424 cases and 645 controls in a population-based case-control study.Unconditional logistic regression models were used to estimate odds ratios (Ors) and 95% confidence intervals (CI) for each occupation, adjusted for age and smoking. Analyses by duration of employment were carried out and interactions with smoking were examined. RESULTS: Male tractor-trailer truck drivers had an elevated risk for bladder cancer (OR = 2.4, CI = 1.4-4.1), with a significant positive trend in risk with increasing duration of employment (P (trend) = 0.0003). Male metal/plastic processing machine operators also had a significant excess (OR = 4.9, CI = 1.6-15.1), attributable mainly to molding/casting machine operators (OR = 16.6, CI = 2.1-131). Elevated risk was also observed for male fabricators, assemblers, and hand workers (OR = 1.8, CI = 1.0-3.4). Women in certain sales occupations (sales clerks, counter clerks, and cashiers) had a significant excess risk (OR = 2.2, CI = 1.3-3.9) and a significant trend with duration of employment (P (trend) = 0.016), as did female health service workers (OR = 4.1, CI = 1.6-10.7; P (trend) = 0.014). There was a positive interaction between smoking and employment as a health service worker (p = 0.036). CONCLUSIONS: These findings are generally consistent with previous studies. Elevated risks for male molding/casting machine operators, female salesworkers, and female health service workers, especially those with a history of smoking, require further investigation.     

GST, NAT, SULT1A1, CYP1B1 genetic polymorphisms, interactions with environmental exposures and bladder cancer risk in a high-risk population

Tobacco smoking and occupation are major risk factors of bladder cancer via exposure to polycyclic aromatic hydrocarbons (PAHs) and aromatic amines. Glutathione S-transferase (GST) M1, T1 and P1 are involved in the detoxification of PAH reactive metabolites. Two N-acetyltransferase isozymes, NAT2 and NAT1, have major roles in catalyzing the N-acetylation and O-acetylation of aromatic amines. Cytochrome p450 1B1 (CYP1B1) and sulfotransferase 1A1 (SULT1A1) are also involved in the metabolism of PAHs and aromatic amines. It is hypothesized that the genetic polymorphisms of these metabolic enzymes have an effect on the individual susceptibility to bladder cancer in particular by interacting with relevant environmental exposures. A hospital-based case-control study among men in Brescia, Northern Italy recruited 201 incidence cases and 214 controls from 1997-2000. Occupational exposures were blindly coded by occupational physicians. Genotyping of polymorphisms were carried out with PCR-RFLP method. Unconditional multivariate logistic regression was applied to model the association between genetic polymorphisms and bladder cancer risk. Effect modifications by age of onset, smoking and occupational exposures to PAHs and aromatic amines were evaluated. We also conducted an analysis of interaction between genetic factors. GSTM1 and GSTT1 null genotype were associated with an increased risk of bladder cancer with an odds ratio (OR) of 1.69 (95% confidence interval [CI] = 1.11-2.56) and 1.74 (95% CI = 1.02-2.95), respectively. The effect of GSTM1 null was seen particularly in heavy smokers, and there was a combined effect with occupational exposure of aromatic amines (OR = 2.77, 95% CI = 1.08-7.10). We observed a trend (p-value < 0.01) of increasing cancer risk comparing subjects with normal GSTM1 and T1 activity to subjects with one (OR = 1.82, 95% CI = 1.16-2.85) or both null genotypes (OR = 2.58, 95% CI = 1.27-5.23). NAT2 slow acetylator was associated with marginally increased risk of bladder cancer (OR = 1.50, 95% CI = 0.99-2.27), and the OR for the joint effect with occupational exposure of aromatic amines was 3.26 (95% CI = 1.06-9.95). SULT1A1 Arg213His polymorphism showed a marginal protective effect. These findings suggest that individual susceptibility to bladder cancer may be modulated by GSTM1, GSTT1 and NAT2 polymorphisms.     

Blood cadmium may be associated with bladder carcinogenesis: the Belgian case-control study on bladder cancer

BACKGROUND: The aim of this study was to assess the relationship between exposure to cadmium and bladder cancer risk. METHODS: We conducted a case-control study in Belgium and measured the blood levels of cadmium in 172 bladder cases and 359 population controls. The data were analyzed as tertiles after logarithmic transformation. Cut-off points were based on the levels among the controls. Logistic regression was performed to calculate odds ratios (ORs) for bladder cancer occurrence with corresponding 95% confidence intervals (95% CI). RESULTS: After adjustment for sex, age, and occupational exposure to PAHs or aromatic amines, the OR for cadmium was 8.3 (95% CI 5.0-13.8) comparing the highest to the lowest tertile (p for trend <0.001). Additional adjustment for smoking (current cigarette smoking status, years of cigarette smoking and number of cigarettes smoked per day) decreased the OR, however it remained strongly significant (OR: 5.7; 95% CI 3.3-9.9). CONCLUSION: Our study suggests that individuals with increased exposure to cadmium have an increased risk of bladder cancer. Future studies should expand on this investigation by studying a larger number of bladder cancer patients and by collecting extensive information on the lifetime occupational, residential, and environmental exposures to clarify the role of cadmium in bladder cancer.     

Occupation and bladder cancer among men in Western Europe

OBJECTIVES: We examined which occupations and industries are currently at high risk for bladder cancer in men. METHODS: We combined data from 11 case-control studies conducted between 1976-1996 in six European countries. The study comprised 3346 incident cases and 6840 controls, aged 30-79 years. Lifetime occupational and smoking histories were examined using common coding. RESULTS: Odds ratios for eight a priori defined high-risk occupations were low, and with the exception of metal workers and machinists (OR = 1.16, 95% CI = 1.02-1.32), were not statistically significant. Higher risks were observed for specific categories of painters, metal, textile and electrical workers, for miners, transport operators, excavating-machine operators, and also for non-industrial workers such as concierges and janitors. Industries entailing a high risk included salt mining, manufacture of carpets, paints, plastics and industrial chemicals. An increased risk was found for exposure to PAHs (OR for highest exposure tertile = 1.23, 95% CI = 1.07-1.4). The risk attributable to occupation ranged from 4.2 to 7.4%, with an estimated 4.3% for exposure to PAHs. CONCLUSIONS: Metal workers, machinists, transport equipment operators and miners are among the major occupations contributing to occupational bladder cancer in men in Western Europe. In this population one in 10 to one in 20 cancers of the bladder can be attributed to occupation.     

Primary liver cancer and occupation in men: a case-control study in a high-incidence area in Northern Italy.

The objective of our study was to evaluate the association between occupation and risk of liver cancer. A hospital-based case-control study was carried out during 1997-1999 in the Province of Brescia, a highly industrialized area in Northern Italy with a high incidence of this neoplasm. The cases were 144 male patients with incident liver cancer (96% hepatocellular carcinoma). Controls were 283 male patients, matched to cases on age (+/-5 years), period and hospital of admission. Information on lifetime occupational history and alcohol consumption was obtained via interview. Specific occupational exposures to pesticides, solvents and other suspected hepatocarcinogens were evaluated. A blood sample was collected to detect hepatitis B and C infections. Odds ratios (OR) of occupational exposure and 95% confidence intervals (CI), adjusted for age, residence, education, heavy alcohol intake, hepatitis B surface antigen and hepatitis C virus antibodies positivity were computed. A statistically significant increased OR was observed for employment in repair of motor vehicles (OR 3.7; 95% CI 1.1-12.3; 9 exposed cases, 10 exposed controls). Increased ORs, although not statistically significant, were found for field-crop farm workers, food and beverage processors, blacksmiths and machine-tool operators, electrical fitters, clerical workers, manufacture of industrial machinery and personal and household services. A slightly increased OR was noted in workers exposed to toluene and xylene (OR 1.4; 95% CI 0.7-3.0, 23 cases, 36 controls); the OR was 2.8 (95% CI 1.0-7.6, 11 cases, 12 controls) for 20 or more years of exposure and 2.0 (95% CI 0.9-4.1, 21 cases, 28 controls) for 30 or more years of time since first exposure. The increase in OR seemed to be independent from that of alcohol or viral infections. Our study showed that the role of occupational exposures in liver carcinogenesis is limited. However, prolonged exposure to organic solvents such as toluene and xylene may represent a risk factor for liver cancer.     

Aromatic amines and cancer

Epidemiological evidence on the relation between aromatic amines and cancer risk is reviewed. In particular, cancer risk in humans resulting from exposure to aromatic amines from occupational sources and tobacco smoking is assessed with reference to ecologic, cohort, and case-control studies. Seven arylamines have been classified by the International Agency for Research on Cancer: benzidine-based dyes and MOCA(4,4'-methylenebis 2-choloroaniline) were considered 'probably' carcinogenic, Group 2A, because of a high level of evidence in experimental animals; two occupational chemicals (2-naphthylamine and benzidine), one drug (Chlornaphazine), and two manufacturing processes (manufacture of auramine and magenta) were included in Group 1 on the basis of 'sufficient' evidence of carcinogenicity in humans. Occupational exposures to aromatic amines explain up to 25 percent of bladder cancers in some areas of Western countries; these estimates might be higher in limited areas of developing countries. Aromatic amines contaminate the ambient air as a component of environmental tobacco smoke. There is increasing evidence that the excess of bladder cancer in smokers is attributable to aromatic amines rather than to other contaminants of tobacco smoke such as polycyclic aromatic hydrocarbons (PAH). A modulating role in the risk of bladder cancer associated with exposure to aromatic amines is played by metabolic polymorphisms, such as the N-acetyltransferase genotype, raising important social and ethical issues. The consistent observation of a difference between men and women in bladder cancer risk, after allowing for known risk factors, suggests consideration of gender-related biological determinants for future investigation.     

Cancer risk from occupational and environmental exposure to polycyclic aromatic hydrocarbons

Epidemiologic evidence on the relationship between polycyclic aromatic hydrocarbons (PAH) and cancer is reviewed. High occupational exposure to PAHs occurs in several industries and occupations. Covered here are aluminum production, coal gasification, coke production, iron and steel foundries, tar distillation, shale oil extraction, wood impregnation, roofing, road paving, carbon black production, carbon electrode production, chimney sweeping, and calcium carbide production. In addition, workers exposed to diesel engine exhaust in the transport industry and in related occupations are exposed to PAHs and nitro-PAHs. Heavy exposure to PAHs entails a substantial risk of lung, skin, and bladder cancer, which is not likely to be due to other carcinogenic exposures present in the same industries. The lung seems to be the major target organ of PAH carcinogenicity and increased risk is present in most of the industries and occupations listed above. An increased risk of skin cancer follows high dermal exposure. An increase in bladder cancer risk is found mainly in industries with high exposure to PAHs from coal tars and pitches. Increased risks have been reported for other organs, namely the larynx and the kidney; the available evidence, however, is inconclusive. The results of studies addressing environmental PAH exposure are consistent with these conclusions.     

Animal-related occupations and the risk of leukemia,myeloma, and non-Hodgkin's lymphoma in Canada

Objective: There is some evidence to suggest that workers in animal-related occupations are at increased risk of developing lymphohematopoietic cancers. This study aimed to examine the risk of leukemia, non-Hodgkin's lymphoma (NHL), and multiple myeloma associated with occupational exposure to animals. Methods: We used data from a multi-site, population-based case–control study using mailed questionnaires which had taken place in eight of ten Canadian provinces, during 1994–1998. There were 1023 leukemia cases, 1577 NHL cases, and 324 multiple myeloma cases (all histologically confirmed) and 4688 population-based controls. Animal-related occupations were identified from a lifetime occupational history. Subjects in animal-related jobs were compared with others using logistic regression for the risk of leukemia, NHL, and multiple myeloma. Results: Compared to subjects without occupational exposure to animals, occupational exposure to beef cattle increased the risks of leukemia (odds ratio (OR) 2.0, 95% confidence interval (CI) 1.2–3.3) and NHL (OR 1.8, 95% CI 1.1–2.9). No other animal exposure was consistently associated with risk of lymphohematopoietic cancer. An unexpected protective association was observed between work as a fisherman and leukemia (OR 0.4, 95% CI 0.2–0.8) and NHL (OR 0.6, 95% CI 0.4–0.9). Conclusions: This population-based case–control study found that those individuals working in occupations associated with beef cattle are at increased risk for developing leukemia and lymphoma while those working in occupations requiring the handling of fish are at decreased risk of leukemia and lymphoma.     

Are the known bladder cancer risk-factors associated with more advanced bladder cancer?

Risk factors for superficial and invasive bladder cancer were examined in a case-control study of 470 cases Identified in 1967–68 in the Brockton and Boston Standard Metropolitan Areas (MA, United States) and of 500 population-based controls. Histologic specimens were reviewed and classified as superficial or invasive, following a standardized protocol. The tobacco-associated risk for superficial bladder cancer was odds ratio (OR)=2.6 (95 percent confidence interval [CI]=1.7–4.1) and the risk for invasive bladder cancer was OR=1.7 (CI=1.1–2.5). For subjects less than 60 years of age, the risks were greater for invasive tumors (OR=4.3, CI=1.2–15) than for superficial tumors (OR=0, CI=0.9–4.2), but this pattern for tobacco use was not found in older subjects. A strong trend of increased risk with increased amount of cigarettes smoked was shown only for invasive bladder tumors. No clear pattern of excess risk for invasive bladder tumors was seen for age at first use and years since last use of tobacco. The risk associated with occupational exposure to aromatic amine bladder carcinogens was OR=1.7 (CI=0.8–3.3) for superficial and OR=1.5 (CI=0.8–3.0) for invasive bladder cancer. For subjects less than 60 years of age, the risks were greater for invasive (OR=12.0, CI=2.1–65) than for superficial tumors (OR=4.3, CI=0.8–24), but this pattern for occupational exposure was not found in older subjects. Risk by age at first exposure to occupational aromaticamine, bladder carcinogens was similar for superficial and invasive tumors. Overall, there was no association between known bladder-cancer risk-factors and more advanced bladder cancer. The relative risk associated with cigarette smoking and occupational exposure to aromatic amines was higher for invasive than superficial cancer only for men less than 60 years of age.Drs Hayes and Zahm are with the Environmental Epidemiology Branch, National Cancer Institute, Bethesda, MD, USA. Authors are affiliated also with the Lucille P. Markey Cancer Center, Lexington, KN, USA (Dr Friedell) and the Department of Epidemiology, University of Alabama, Birmingham, AL, USA (Dr Cole). Address correspondence to Dr Hayes, Environmental Epidemiology Branch, National Cancer Institute, EPN 418, Bethesda, MD 20892, USA.     

Cancer risk among Finnish food industry workers

Occupational cancer risks suggested among food industry workers are inconclusive. The objective of our study was to assess associations between different cancers and working in the food industry in Finland. The carcinogenic exposures are mainly inhalatory, and we were therefore interested in respiratory cancers in particular. We followed up a cohort of all economically active Finns born between 1906 and 1945 for 30 million person-years during 1971-95. The 1970 Census data on occupations were linked with data on subsequent incident cancer cases. Standardized incidence ratios (SIR) and 95% confidence intervals (CI) were calculated for each occupation using the economically active population as the reference. A total of 2,526 incident cancer cases were observed. Elevated risks were observed among male food industry workers for pancreatic (SIR=1.50, CI=1.13-1.96) and kidney cancers (1.51, 1.16-1.94). With respect to specific occupations, there was an excess of lung cancer among female bakers (1.38, 1.01-1.85) and laryngeal cancer among male grain millers (2.60, 1.05-5.36). Occupational exposure is unlikely to be a major risk factor for cancer among Finnish workers employed in typical food industry occupations.     

A case–control study of occupational risk factors for bladder cancer in Canada

Objective: To investigate occupational risk factors for bladder cancer in seven Canadian provinces. Methods: We analysed a population-based case–control dataset of 887 individuals with incident, histologically confirmed bladder cancer between 1994 and 1997. Controls (2847) frequency matched for age and gender were surveyed in 1996. Questionnaires were returned by about 60% of subjects. Odds ratios (ORs) for occupations and self-reported exposures were adjusted for province, age, race, smoking, and several dietary factors, using unconditional logistic regression. Results: Statistically significant increased risks were observed among men employed as hairdressers (OR=3.42; 1.09–10.8), primary metal workers (OR = 2.40; 1.29–4.50), miners (OR = 1.94; 1.18–3.17), and automechanics (OR = 1.69; 1.02–2.82). Primary metal workers and automechanics showed evidence of an employment duration–response trend. Modest elevated risks that were not significant were also observed for male government inspectors, printers, firefighters, general labourers, and welders. A duration–response trend was evident for government inspectors and general labourers. For females, significant elevations were observed among lumber processors (OR = 8.78; 1.28–60.1), general labourers (OR = 2.18; 1.05–4.52), nurses (OR = 1.54; 1.03–2.31), and general clerks (OR = 1.48; 1.01–2.17). The latter showed a positive duration–response trend. Conclusions: This study found a statistically significant excess risk of bladder cancer, with a duration–response trend, among male primary metal workers and automechanics, and female office workers engaged in general clerical duties.     

Case-control study of high risk occupations for bladder cancer in New Zealand

We conducted a nationwide case-control study of bladder cancer in adult New Zealanders to identify occupations that may contribute to the risk of bladder cancer in the New Zealand population. A total of 213 incident cases of bladder cancer (age 25-70 years) notified to the New Zealand Cancer Registry during 2003 and 2004, and 471 population controls, were interviewed face-to-face. The questionnaire collected demographic information and a full occupational history. The relative risks for bladder cancer associated with ever being employed in particular occupations and industries were calculated by unconditional logistic regression adjusting for age, sex, smoking and socio-economic status. Estimates were subsequently semi-Bayes adjusted to account for the large number of occupations and industries being considered. An elevated bladder cancer risk was observed for hairdressers (odds ratio (OR) 9.15 95% Confidence Interval (95%CI) 1.60-62.22), and sewing machinists (OR 3.07 95%CI 1.35-6.96). Significantly increased risks were not observed for several other occupations that have been reported in previous studies, including sales assistants (OR 1.03 95%CI 0.64-1.67), painters and paperhangers (OR 1.42 95%CI 0.56-3.60), sheet metal workers (OR 0.39, 95%CI 0.15-1.00), printing trades workers (OR 1.11 95%CI 0.41-3.05) and truck drivers (OR 1.36 95%CI 0.60-3.09), although the elevated odds ratios for painters, printers and truck drivers are consistent with excesses observed in other studies. Nonsignificantly increased risks were observed for tailors and dressmakers (OR 2.84 95%CI 0.62-13.05), rubber and plastics products machine operators (OR 2.82 95%CI 0.75-10.67), building workers (OR 2.15, 95%CI 0.68-6.73), and female market farmers and crop growers (OR 2.05 95%CI 0.72-5.83). In conclusion, this study has confirmed that hairdressers and sewing machinists are high risk occupations for bladder cancer in New Zealand, and has identified several other occupations and industries of high bladder cancer risk that merit further study.     

Occupation and bladder cancer in European women

Objectives: We examined the importance of occupational exposures for bladder cancer in women.Methods: We combined data from 11 case-control studies conducted between 1976 and 1996 in six European countries. The pooled data comprised 700 incident female cases and 2425 population or hospital controls, aged 30–79 years. Lifetime occupational and smoking history were examined using common coding.Results: Excess risks were found in only a few of the occupations previously identified at high risk for bladder cancer. Statistically significant excess risks were observed for metal workers, particularly blacksmiths, toolmakers and machine tool operators (OR: 2.0, 95% CI: 1.1–3.6), tobacco workers (OR: 3.1, 95% CI: 1.1–9.3), field crop and vegetable farm workers (OR: 1.8, 95% CI: 1.0–3.1), tailors and dress makers (OR: 1.4, 95% CI: 1.0–2.1), saleswomen (OR: 2.6, 95% CI: 1.0–6.9), and mail sorting clerks (OR: 4.4, 95% CI: 1.0–19.5). About 8% (95% CI: 3.1–19.9) of all bladder cancers in women could be attributed to occupation after adjusting for smoking. The attributable risk was higher in women aged less than 65 years (12%), compared to older women (4%).Conclusions: The calculation of the attributable risk on the basis of results from this analysis may have caused some overestimation of the proportion of occupational bladder cancer in women. A significant proportion, however, of bladder cancer cases among European women less than 65years is likely to be attributed to occupation. This link between bladder cancer in women and occupational factors has received little recognition, probably because studies addressing these issues have predominantly been done in men.     

Genetic polymorphisms of MPO, COMT, MnSOD, NQO1, interactions with environmental exposures and bladder cancer risk

Tobacco smoking and occupational exposure are major risk factors of bladder cancer via exposure to polycyclic aromatic hydrocarbons (PAHs) and aromatic amines, which lead to oxidative stress and DNA damage. Several enzymes, which play key roles in oxidative stress are polymorphic in humans. Myeloperoxidase (MPO) produces a strong oxidant for microbicidal activity, and activates carcinogens in tobacco smoke. Catechol-O-methyltransferase (COMT) catalyzes the methylation of endo- and xenobiotics and prevents redox cycling. NAD(P)H:quinone oxidoreductase (NQO1) catalyzes the two-electron reduction of quinoid compounds, which also protects cells from redox cycling. Manganese superoxide dismutase (MnSOD) protects cells from free radical injury. To test the hypothesis that the risk of bladder cancer can be influenced by polymorphisms in the genes that modulate oxidative stress, in particular by interacting with environmental carcinogens, we conducted a hospital-based case-control study among men in Brescia, Northern Italy. We recruited and interviewed 201 incident cases and 214 controls from 1997 to 2000. Occupational exposures to PAHs and aromatic amines were coded blindly by occupational physicians. Unconditional multivariate logistic regression was applied to model the association between genetic polymorphisms and bladder cancer risk and the effect of modifications of smoking and occupational exposures were evaluated. MPO G-463A homozygous variant was associated with a reduced risk of bladder cancer with an OR of 0.31 (95% CI = 0.12-0.80). MnSOD Val/Val genotype increased the risk of bladder cancer with OR of 1.91 (95% CI = 1.20-3.04), and there was a combined effect with smoking (OR = 7.20, 95% CI = 3.23-16.1) and PAH (OR = 3.02, 95% CI = 1.35-6.74). We did not observe an effect of COMT Val108Met polymorphism. These findings suggest that individual susceptibility of bladder cancer may be modulated by MPO and MnSOD polymorphisms, and that the combination of genetic factors involved in oxidative stress response with environmental carcinogens may play an important role in bladder carcinogenesis.     

Occupational exposures as risk factors for gastric cancer in Italy

Occupational associations with gastric cancer were investigated in a multicenter case-control study in Italy involving interviews with 640 histologically confirmed male cases and 959 controls, randomly selected from the resident populations of the study areas. From information on the three jobs each person held the longest, risks were evaluated according to employment in 35 occupations (ever or 21+ years) and to estimated exposure (ever or 21+ years) to six chemicals using a job-exposure matrix. All risk estimates were adjusted by personal, demographic, and dietary variables identified as gastric-cancer risk factors in previous analyses. The only significantly increased risk was observed for sailors, seamen, and allied groups (ever employed: odds ratio [OR]=2.9; 95 percent confidence interval [CI]=1.1–8.0; 21+ years: OR=3.1, CI=0.8–13). Nonsignificant increases after 21+ years of employment were observed for forestry workers, miners, and janitors and cleaners. Crude ORs were elevated significantly among farmers, but adjusting for demographic and lifestyle factors largely eliminated the association: a nonsignificant 30 percent excess risk remained for farm laborers, but there was no rise in risk among long-term farm laborers and no excess among farm owners. Application of the job-exposure matrix revealed excess risks of borderline significance associated with potential exposure to mineral dusts and nitrogen oxides. For subjects with 21+ years of potential exposure, nonsignificantly increased risks were related to mineral dusts, asbestos, fertilizers, and nitrosamines. Although possibly incomplete occupational histories and use of broad occupational codes likely resulted in some exposure misclassification, the results of this study indicate that occupation in general is not a strong risk factor for gastric cancer. The findings, however, are consistent with previous reports suggesting that certain occupational exposures may influence gastric cancer risk.This work was made possible by the financial support of the International Union against Cancer, Geneva, Switzerland, and the National Research Council, Rome, Italy.     

Decreased risk of lung cancer in the cotton textile industry of Shanghai

The relationship between lung cancer risk and work in the cotton textile industry was investigated in a large population-based case-control study in urban Shanghai, where the industry is a major employer of men and women. Personal interviews obtained occupational, smoking, and other information from 1405 newly diagnosed lung cancer cases and 1495 controls. A significantly low risk of lung cancer was associated with cotton textile employment [odds ratio (OR) = 0.7,95% confidence interval (CI) = 0.6-0.9]. In men, the decreased risk was observed among both smokers (OR = 0.7, 95% CI = 0.5-1.1) and nonsmokers (OR = 0.3, 95% CI = 0.1-1.0). In women, the risk was also decreased regardless of smoking status (OR = 0.8, 95% CI = 0.4-1.6 among smokers; OR = 0.9, 95% CI = 0.6-1.2 among nonsmokers). In both sexes, the reductions in risk tended to be greater for lung cancer cell types other than adenocarcinoma. Low risks were found regardless of occupations within the cotton textile industry; the OR for workers in textile processing who potentially had greater dust exposure was 0.8 (95% CI = 0.6-1.2), whereas the OR for those in other industry jobs was 0.7 (95% CI = 0.4-1.0). There was little difference in risk according to self-reported exposure to textile dust, and no clear trend with duration of employment or dust exposure. Reasons for the reduced risk of lung cancer in cotton textile workers without a dose response are unclear, although several methodological explanations were considered. The findings, however, appear consistent with prior epidemiological studies and are interesting in light of speculation about tumor-inhibitory factors, such as bacterial endotoxins, that are found in dusts from cotton and other fiber crops.     

Schistosomiasis and the risk of bladder cancer in Alexandria, Egypt.

The relationship between history of schistosomiasis and bladder cancer risk was investigated using data from a case-control study conducted between January 1994 and July 1996 in Alexandria, Egypt. Cases were 190 subjects with incident, histologically confirmed invasive cancer of the bladder, and controls were 187 subjects admitted to hospital for acute, non-neoplastic, non-urinary tract conditions. Eighty-six cases (45%) vs 69 controls (37%) reported a history of urinary schistosomiasis. The corresponding multivariate odds ratio (OR) of bladder cancer -- after allowance for age, sex, education, smoking, other urinary infections and high-risk occupations -- was 1.72 (95% confidence interval (CI) 1.0-2.9). The ORs were 0.22 (95% CI 0.1-0.4) for intestinal schistosomiasis and 0.32 (95% CI 0.1-1.9) for schistosomiasis of other types. The OR for urinary schistosomiasis was higher in subjects who were younger at first diagnosis (OR of 3.3 for <15 years) and in those with a long time since first diagnosis (OR of 3.0 for > or = 35 years). The ORs were 15.8 for male ever-smokers with a history of urinary schistosomiasis, compared with never-smokers without such a history, and 3.2 for men ever-infected with urinary Schistosoma haematobium and ever-employed in high-risk occupations, compared with those never-infected and with no high-risk occupational history. This study confirms that clinical history of urinary schistosomiasis is significantly, but modestly, associated with increased bladder cancer risk, explaining some 16% of bladder cancer cases in this Egyptian population.     

Nested Case-control Study of Occupational Radiation Exposure and Breast and Esophagus Cancer Risk among Medical Diagnostic X Ray Workers in Jiangsu of China

Medical diagnostic X-ray workers are one occupational group that expose to the long-term low-dose externalradiation over their working lifetime, and they may under risk of different cancers. This study aims to determinethe relationship between the occupational X-ray radiation exposure and cancer risk among these workers inJiangsu, China. We conducted Nested case-control study to investigate the occupational X-ray radiation exposureand cancer risk. Data were collected through self-administered questionnaire, which includes but not limitsto demographic data, personal behaviors and family history of cancer. Retrospective dose reconstruction wasconducted to estimate the cumulative doses of the x-ray workers. Inferential statistics, t-test and 2 tests wereused to compare the differences between each group. We used the logistic regression model to calculate the oddsratio (OR) and 95% confidence interval (CI) of cancer by adjusting the age, gender. All 34 breast cancer casesand 45 esophageal cancer cases that detected in a cohort conducted among health workers between 1950~2011were included in this presented study, and 158 cancer-free controls were selected by frequency-matched (1:2).Our study found that the occupational radiation exposure was associated with a significantly increased cancerrisk compared with the control, especially in breast cancer and esophageal cancer (adjusted OR=2.90, 95% CI:1.19-7.04 for breast cancer; OR=4.19, 95% CI: 1.87-9.38 for esophageal cancer, and OR=3.43, 95% CI: 1.92-6.12for total cancer, respectively). The occupational X-ray radiation exposure was associated with increasing cancerrisk, which indicates that proper intervention and prevention strategies may be needed in order to bring downthe occupational cancer risk.     

Occupational exposure to dusts and risk of renal cell carcinoma

Background:

Occupational exposures to dusts have generally been examined in relation to cancers of the respiratory system and have rarely been examined in relation to other cancers, such as renal cell carcinoma (RCC). Although previous epidemiological studies, though few, have shown certain dusts, such as asbestos, to increase renal cancer risk, the potential for other occupational dust exposures to cause kidney damage and/or cancer may exist. We investigated whether asbestos, as well as 20 other occupational dust exposures, were associated with RCC risk in a large European, multi-center, hospital-based renal case–control study.

Methods:

General occupational histories and job-specific questionnaires were reviewed by occupational hygienists for subject-specific information. Odds ratios (ORs) and 95% confidence intervals (95% CIs) between RCC risk and exposures were calculated using unconditional logistic regression.

Results:

Among participants ever exposed to dusts, significant associations were observed for glass fibres (OR: 2.1; 95% CI: 1.1–3.9), mineral wool fibres (OR: 2.5; 95% CI: 1.2–5.1), and brick dust (OR: 1.5; 95% CI: 1.0–2.4). Significant trends were also observed with exposure duration and cumulative exposure. No association between RCC risk and asbestos exposure was observed.

Conclusion:

Results suggest that increased RCC risk may be associated with occupational exposure to specific types of dusts. Additional studies are needed to replicate and extend findings.