Systematic review and meta-analysis of epidemiological literature evaluating the association between exposure to man-made vitreous fibers and respiratory tract cancers.

We conducted a systematic review and meta-analysis of epidemiological studies that evaluated occupational exposure to man-made vitreous fibers (MMVF) including glass, rock, and slag wools, and respiratory tract cancers (RTC) including cancers of the larynx, trachea, bronchus, and lung. The MEDLINE/PubMed and Web of Science databases were searched in order to identify epidemiological studies that evaluated the association between occupational MMVF exposure and RTCs. We performed random-effects meta-analyses of relevant studies identified by our literature search, and evaluated sources of between-study heterogeneity. The pooled relative risk (RR) of RTC among workers exposed to MMVFs was 1.09 (95% CI = 0.97, 1.22). The RR was closer to 1.0 when limiting the analysis to effect estimates from studies that accounted for the main a priori risk factors for RTC, asbestos exposure and smoking (RR = 1.03, 95% CI = 0.90, 1.18). Overall, our synthesis of the epidemiological literature suggests that occupational MMVF exposure is not associated with risk of RTC.

Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment.

In 2010, the World Health Organization (WHO) established an indoor air quality guideline for short- and long-term exposures to formaldehyde (FA) of 0.1 mg/m3 (0.08 ppm) for all 30-min periods at lifelong exposure. This guideline was supported by studies from 2010 to 2013. Since 2013, new key studies have been published and key cancer cohorts have been updated, which we have evaluated and compared with the WHO guideline. FA is genotoxic, causing DNA adduct formation, and has a clastogenic effect; exposure-response relationships were nonlinear. Relevant genetic polymorphisms were not identified. Normal indoor air FA concentrations do not pass beyond the respiratory epithelium, and therefore FA's direct effects are limited to portal-of-entry effects. However, systemic effects have been observed in rats and mice, which may be due to secondary effects as airway inflammation and (sensory) irritation of eyes and the upper airways, which inter alia decreases respiratory ventilation. Both secondary effects are prevented at the guideline level. Nasopharyngeal cancer and leukaemia were observed inconsistently among studies; new updates of the US National Cancer Institute (NCI) cohort confirmed that the relative risk was not increased with mean FA exposures below 1 ppm and peak exposures below 4 ppm. Hodgkin's lymphoma, not observed in the other studies reviewed and not considered FA dependent, was increased in the NCI cohort at a mean concentration ≥0.6 mg/m3 and at peak exposures ≥2.5 mg/m3; both levels are above the WHO guideline. Overall, the credibility of the WHO guideline has not been challenged by new studies.

[The opponent you do not just imagine. The case of Falconara Marittima (Marche Region, Central Italy)]. / EPICHANGE/2. L'avversario che non ti aspetti. Il caso di Falconara Marittima.

Falconara Marittima (Marche Region, Central Italy) is declared to be an area at high risk of environmental crisis, due to the presence of a refinery plant. In 2004, Marche Region funded an epidemiological survey to assess atmospheric risks linked to the refinery. This survey was conducted by the Italian National Cancer Institute of Milan, and citizens actively contributed. An excess for leukaemias and an increase in non-Hodgkin lymphomas were showed. These results were confirmed also by the Regional Environmental Protection Agency and the Regional Health Authority. But Marche Region and the Municipalities chose to not report the situation: the same Institutions, which at the beginning sided the citizens, became an opponent for health protection.

[Respiratory cancers attributable to occupational exposures: what is the cost to society in France]. / Cancers des voies respiratoires attribuables aux expositions professionnelles : quels coûts pour la société française ?

OBJECTIVE: To estimate the social cost of respiratory cancers attributable to occupational risk factors in France in 2010. METHODS: We estimated the number of cases of respiratory cancers attributable to each identified occupational risk factor according to the attributable fractions method. We also estimated direct (costs of hospital stays, drugs, outpatient care) and indirect costs (production losses) related to morbidity (absenteeism and presenteeism) and mortality (years of lost production). Production losses for paid work and unpaid domestic activities were taken into account. RESULTS: The social cost of respiratory cancers (lung, larynx, sinonasal, pleural mesothelioma) attributable to exposure to asbestos, chromium, diesel engine exhaust, polycyclic aromatic hydrocarbons, painting occupations (unidentified carcinogen), crystalline silica, wood and leather dust in France in 2010 was estimated to be between €960 and 1,866 million. The cost of lung cancer represents between €804 and 1,617 million. The three risk factors with the greatest impact are asbestos (€530 to 890 million), diesel engine exhaust (€227 to 394 million), and crystalline silica (€116 to 268 million). CONCLUSION: These results provide a conservative estimate of the public health and economic burden of respiratory cancers attributable to occupational risk factors from a societal perspective.

Genotoxic properties of XLR-11, a widely consumed synthetic cannabinoid, and of the benzoyl indole RCS-4.

Aim of this study was the investigation of the genotoxic properties of XLR-11 [1-(5-fluoropentyl)-1H-indol-3-yl](2,2,3,3-tetramethylcyclopropyl)methanone, a widely consumed synthetic cannabinoid (SC), and of the benzoyl indole RCS-4 (4-methoxyphenyl)(1-pentyl-1H-indol-3-yl)methanone). We characterized the DNA-damaging properties of these drugs in different experimental systems. No evidence for induction of gene mutations was detected in bacterial (Salmonella/microsome) tests, but clear dose-dependent effects were found in in vitro single cell gel electrophoresis (SCGE) assays with human lymphocytes and with buccal- and lung-derived human cell lines (TR-146 and A-549). These experiments are based on the determination of DNA migration in an electric field and enable the detection of single- and double-strand breaks and apurinic sites. Furthermore, we found that both drugs induce micronuclei which are formed as a consequence of chromosomal aberrations. The lack of effects in SCGE experiments with lesion-specific enzymes (FPG, Endo III) shows that the DNA damage is not caused by formation of oxidatively damaged bases; experiments with liver enzyme homogenates and bovine serum albumin indicate that the drugs are not converted enzymatically to DNA-reactive intermediates. Furthermore, results with buccal- and lung-derived human cells show that gaseous treatment of the cells under conditions which reflect the exposure situation in drug users may cause damage of the genetic material in epithelia of the respiratory tract. Since DNA instability is involved in the etiology of cancer, these findings can be taken as an indication that consumption of the SCs may cause tumors in the respiratory tract of consumers.

IMPACT OF SOME ENVIRONMENTAL FACTORS ON HUMAN HEALTH.

This paper presents statistical data of 2012-2015 on the diseases caused by the atmospheric air and water pollutions in Ajara region. The research on the content of dust, sulfur dioxide and nitrogen dioxide as well as carbon monoxide in the atmospheric air was held together with the National Environment Agency Ajara Monitoring Service. The results of the research have shown that the average content of the dust reached its maximum in 2012 (0.60 mg/m3) and it dropped to the minimum in 2015 (0.441 mg/m3). As for average content of carbon monoxide the maximum was observed in 2013 (3.1 mg/m3) and minimum in 2015 (2.1 mg/m3). Average content of the sulfur dioxide was at maximum in 2015 (0.159 mg/m3) and at minimum in 2012 (0.07 mg/m3). The average content of nitrogen dioxide reached its maximum in 2015 (0.153 mg/m3) and was found to be at its minimum in 2012 (0.13 mg/m3). In parallel statistical research of the registered diseases (chronic and undetermined bronchitis, asthma, allergic rhinitis and trachea/bronchi/lung malignant cancer) in Ajara during 2012-2015 has been performed. These diseases were especially common among the population over the age of 40. It may be concluded that in 2015 the cases of diseases caused by the atmospheric air pollution in Ajara have become more frequent compared to the previous years. Therefore, it is evident that monitoring of atmosphere air should be improved and corresponding preventive measures should be undertaken.

Aspirin and non-steroidal anti-inflammatory drug use and the risk of upper aerodigestive tract cancer.

BACKGROUND: Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) are widely used as analgesics and preventative agents for vascular events. It is unclear whether their long-term use affects cancer risk. Data on the chemopreventative role of these drugs on the risk of the upper aerodigestive tract cancer (UADT) are insufficient and mostly refer to oesophageal cancer. The aim of this study was to investigate the effect of aspirin and other NSAIDs on the risk of UADT cancers. METHODS: A nested case-control study using the Primary Care Clinical Informatics Unit (PCCIU) database. Conditional logistics regression was used for data analysis. RESULTS: There were 2392 cases of UADT cancer diagnosed between 1996 and 2010 and 7165 age-, gender- and medical practice-matched controls from 131 general medical practices. Mean age of cases was 66 years (s.d. 12) and most were male (63%). Aspirin was prescribed in a quarter of cases and controls, COX-2 inhibitors in 4% of cases and 5% of controls and other NSAIDs in 33% of cases and 36% of controls. Aspirin prescription was associated with a nonsignificant risk reduction of cancer of UADT (adjusted OR=0.9, 95% CI=0.8, 1.0), head and neck (HN; adjusted OR=0.9, 95% CI=0.7, 1.1) or the oesophagus (adjusted OR=0.8, 95% CI=0.7, 1.0). Similar results were found for COX-2 inhibitors prescription. Prescription of other NSAIDs was associated with significantly reduced risk of cancer of UADT (adjusted OR=0.8, 95% CI=0.7, 0.9), HN (adjusted OR=0.8, 95% CI=0.7, 0.9) and the oesophagus (adjusted OR=0.8, 95% CI=0.7, 0.9). An increased volume of aspirin prescriptions was associated with a significant risk reduction (test for trend P<0.001). CONCLUSIONS: The decreased risk of cancer of the UADT associated with the use of non-COX-2 inhibitors, NSAIDs and long-term aspirin therapy warrants further exploration of the benefits vs risks of the use of these agents.

Occupational exposures to polycyclic aromatic hydrocarbons and respiratory and urinary tract cancers: an updated systematic review and a meta-analysis to 2014.

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with an excess risk of respiratory tract and bladder cancers in several industries, but the issue requires further quantification. We updated a previous systematic review by reviewing in details cohort studies on workers employed in selected industries with potential PAH exposure published between 2006 and 2014, and we summarized through a meta-analytic approach the main results of all available cohort studies published between 1958 and 2014 investigating cancers of the respiratory and urinary tracts. Thirteen papers on cohort studies investigating cancer risk in workers exposed to PAHs were retrieved through the literature search. These included workers from aluminum production industries (seven studies), iron and steel foundries (two studies), asphalt workers (two studies), and carbon black production (two studies). In the meta-analysis, an excess risk of respiratory tract cancers (mainly lung cancer) was found in iron and steel foundries [pooled relative risk (RR) 1.31, 95 % confidence interval (CI) 1.08-1.59 from 14 studies], while a weak excess risk (pooled RR 1.08, 95 % CI 0.95-1.23 from 11 studies) emerged for aluminum production. A borderline increase risk was also observed for cancer of the bladder in the aluminum production (pooled RR 1.28, 95 % CI 0.98-1.68 from 10 studies) and in iron and steel foundries (pooled RR 1.38, 95 % CI 1.00-1.91 from 9 studies). This updated review and meta-analysis confirm the increased risk from respiratory tract and bladder cancers in selected PAH-related occupations. It cannot be ruled out whether such excesses are due, at least in part, to possible bias or residual confounding.

Mesothelioma associated with use of drywall joint compound: a case series and review of literature.

BACKGROUND: Drywall joint compound contained asbestos fibers, primarily chrysotile, in the 1950s through the 1970s. Workers in a variety of construction trades and homeowners were exposed to respirable asbestos from the use of these products, including during handling, mixing, sanding, and sweeping. Disturbance of in-place asbesto-containing joint compound continues to be a potential source of exposure during demolition or repair of wallboard. Studies from the 1970s and 1980s report air fiber measurements above current and historic regulatory limits during intended usage, and typical asbestos-related disease in drywall construction workers. OBJECTIVES: We present three cases of mesothelioma in which the only known exposure to asbestos was from joint compound and review the literature on exposure circumstances, dose and fiber types. CONCLUSIONS: Physicians treating mesothelioma patients should obtain a history of exposure to these products during work or home remodeling.

Assessing specific causation of mesothelioma following exposure to chrysotile asbestos-containing brake dust.

BACKGROUND: The question of whether chrysotile asbestos-containing brake dust can plausibly serve as a cause of mesothelioma in an exposed individual has become a matter of heated debate in the medical literature despite multiple international, federal, and state governmental agencies acknowledging a causal association. OBJECTIVES: We describe and provide an analysis of various industry and academic perspectives contributing to the debate. METHODS: A framework is presented for evaluating the general and specific causal relationship between brake dust exposure and mesothelioma utilizing the principles of forensic epidemiology, and by applying the Bradford-Hill criteria. RESULTS AND CONCLUSIONS: We conclude that there is a "net" of evidence favoring a causal relationship between brake dust-associated chrysotile exposure and mesothelioma. The industry-sponsored position that there is insufficient evidence to support a contiguous "chain" of causation is specious from both a methodologic and evidentiary perspective. Finally, we suggest a semiquantitative approach for the evaluation of individual causation in putative cases of mesothelioma with a history of significant brake dust exposure.

Treatment of kidney transplant recipients with ACEi/ARB and risk of respiratory tract cancer: a collaborative transplant study report.

Whether treatment with angiotensin-converting enzyme inhibitors (ACEi) and/or angiotensin receptor blockers (ARB) increases the risk of cancer is controversial. Collaborative transplant study data were analyzed according to whether kidney transplant recipients were treated with ACEi/ARB at year 1. Twenty-four thousand and ninety patients were studied of whom 9079 (38%) patients received ACEi/ARB. There were 872 nonskin malignancies during years 2-8 posttransplant, including 107 respiratory/intrathoracic tumors. The standardized incidence ratio (SIR) for all nonskin malignancies was similar between the ACEi/ARB (1.91) and no ACEi/ARB (1.81) groups (p = 0.42). For respiratory/intrathoracic tumors, however, SIR was significantly higher with ACEi/ARB (1.65 vs. 1.09 for no ACEi/ARB, p = 0.033). Multivariate Cox regression analysis showed that ACEi/ARB treatment was not associated with an increased risk of respiratory/intrathoracic tumors in nonsmokers. In patients with a history of smoking, however, the risk of respiratory/intrathoracic tumors was 2.77 (95% CI 1.19-6.43, p = 0.018) in patients without ACEi/ARB treatment as compared to 7.10 (95% CI 3.27-15.4, p < 0.001) in patients treated with ACEi/ARB. Our data indicate that in kidney transplant recipients, ACEi/ARB treatment is associated with a significant increase in the rate of respiratory/intrathoracic tumors in the subpopulation of patients with a history of smoking.

Reconstruction of historical exposures in the US nickel alloy industry and the implications for carcinogenic hazard and risk assessments.

Recently, various regulatory authorities have been reexamining the potential carcinogenic hazards and risks associated with exposures to nickel and certain nickel compounds. In making their assessments, the authorities have focused on occupational cohorts at facilities where nickel-containing sulfidic ores were processed and where increased lung and nasal cancer risks were found in specific groups of workers. Little attention, however, has been paid to the vast number of workers in nickel-using industries, where no excess respiratory cancer risks have been observed. In this paper, the historical exposures of one such group of workers engaged in the production of nickel alloys are reconstructed, and the implications for cancer risk assessments are analyzed. The results indicate that nickel alloy workers were exposed to insoluble oxidic and metallic nickel species at levels comparable to those found in certain nickel processing cohorts; yet they experienced no increase in respiratory cancer risks. This suggests that extrapolating risks from certain primary nickel producers to other nickel industry sectors may not be appropriate.

[Influence of vehicular traffic density on hospital admissions due to respiratory tract cancer in the city of São Paulo, Brazil]. / Influência da densidade de tráfego veicular na internação por câncer do aparelho respiratório no Município de São Paulo, Brasil.

Pollution related to traffic is a major problem in urban centers and a large portion of the population is vulnerable to its health effects. This study sought to identify a potential association between hospital admissions due to respiratory tract cancer and vehicular traffic density in the city of São Paulo, Brazil. It is an ecological study of the public (Hospital Inpatient Authorization - AIH, in Portuguese) and private (Hospital Inpatient Communication - CIH, in Portuguese) health care systems, from 2004 to 2006, geocoded by individuals' residential addresses. Using a Besag-York-Mollié ecological model, we initially evaluated the relationship between number of cases of hospital admission due to respiratory tract cancer in each weighting area and the standardized co-variables: traffic density and Municipal Human Development Index (MHDI) as indicator of socioeconomic status. Using a classic Poisson model, we then evaluated the risk associated with growing traffic density categories. The Besag-York-Mollié model estimated a RR = 1.09 (95%CI: 1.02-1.15) and RR = 1.19 (95%CI: 1.10-1.29) of admission due to respiratory tract cancer for each increase of one standard deviation of traffic and MHDI, respectively. The Poisson model also showed a clear exposure-response gradient for admission due to respiratory tract cancer (IRR = 1.11; 95%CI: 1.07-1.15, for each 10 units of added traffic density). This study suggests that there is an association between residing in areas with high traffic density and hospital admissions due to respiratory tract cancer in the city of São Paulo.

A poluição relacionada ao tráfego é um grande problema nos centros urbanos, e uma grande parcela da população fica vulnerável aos seus efeitos à saúde. Este trabalho teve como objetivo identificar potencial associação entre as internações hospitalares por câncer do aparelho respiratório com a densidade de tráfego veicular no Município de São Paulo, Brasil. É um estudo ecológico com dados de internações hospitalares por câncer dos sistemas público (Autorização de Internação Hospitalar - AIH) e particular (Comunicação de Internação Hospitalar - CIH), de 2004 a 2006, geocodificados por endereço de residência do indivíduo. Mediante um modelo ecológico de Besag-York-Mollié foi avaliada inicialmente a relação entre o número de casos de internação por câncer do aparelho respiratório em cada área de ponderação e as covariáveis padronizadas: densidade de tráfego e Índice de Desenvolvimento Humano Municipal (IDHM) como indicador de status socioeconômico. Sequencialmente, com um modelo clássico de Poisson, procedeu-se uma avaliação do risco associado às categorias crescentes de densidade de tráfego. O modelo de Besag-York-Mollié estimou um RR = 1,09 (IC95%: 1,02-1,15) e RR = 1,19 (IC95%: 1,10-1,29) de internação por câncer do aparelho respiratório, para cada aumento de um desvio padrão da densidade de tráfego e IDHM, respectivamente. Foi também evidenciado pelo modelo de Poisson um claro gradiente de exposição-resposta para internação por câncer respiratório (IRR = 1,11; IC95%: 1,07-1,15, para cada dez unidades de acréscimo da densidade de tráfego). Este trabalho sugere que há associação entre residir em áreas com alta densidade de tráfego e internação por câncer do aparelho respiratório no Município de São Paulo.

La contaminación relacionada con el tráfico es un gran problema en los centros urbanos, y una gran parte de la población es vulnerable a sus efectos para la salud. El objetivo de este trabajo fue identificar la potencial asociación entre los internamientos hospitalarios por cáncer del aparato respiratorio con la densidad del tráfico vehicular en el Municipio de São Paulo, Brasil. Es un estudio ecológico con datos de internamientos hospitalarios por cáncer de los sistemas público (Autorización de Internación Hospitalaria - AIH) y particular (Comunicación de Internación Hospitalaria - CIH), de 2004 a 2006, geocodificados por dirección de residencia del individuo. Mediante el modelo ecológico de Besag-York-Mollié se evaluó inicialmente la relación entre el número de casos de internamiento por cáncer del aparato respiratorio en cada área de ponderación y covariables estandarizadas: densidad de tráfico e Índice de Desarrollo Humano Municipal (IDHM), como indicador de estatus socioeconómico. Secuencialmente, con un modelo clásico de Poisson, se procedió a una evaluación del riesgo asociado a las categorías crecientes de densidad de tráfico. El modelo de Besag-York-Mollié estimó un RR = 1,09 (IC95%: 1,02-1,15) y RR = 1,19 (IC95%: 1,10-1,29) de internamiento por cáncer del aparato respiratorio, para cada aumento de un desvío estándar de la densidad de tráfico e IDHM, respectivamente. Se evidenció también, a través del modelo de Poisson, un claro gradiente de exposición-respuesta para el internamiento por cáncer respiratorio (IRR = 1,11; IC95%: 1,07-1,15, para cada 10 unidades de incremento de la densidad de tráfico). Este trabajo sugiere que existe una asociación entre residir en áreas con alta densidad de tráfico y el internamiento por cáncer del aparato respiratorio en el Municipio de São Paulo.

Respiratory cancer and inhaled inorganic arsenic in copper smelters workers: a linear relationship with cumulative exposure that increases with concentration.

BACKGROUND: Inhalation of high levels of airborne inorganic arsenic is a recognized cause of respiratory cancer. Although multiple epidemiologic studies have demonstrated this association, there have been few analyses of the mathematical relationship between cumulative arsenic exposure and risk of respiratory cancer, and no assessment as to whether and how arsenic concentration may modify this association. OBJECTIVES: The objective is an evaluation of the shape of the relationship between respiratory cancer mortality and cumulative inhaled arsenic exposure among copper smelter workers, and the modification of that relationship by arsenic concentration. METHODS: We used Poisson regression methods to analyze data from a cohort of arsenic-exposed copper smelter workers under a linear-exponential model for the excess relative risk. RESULTS: Within categories of arsenic concentration, the association between respiratory cancer and cumulative arsenic exposure was consistent with linearity. The slope of the linear relationship with cumulative exposure increased with increasing arsenic concentration category. CONCLUSIONS: Our results suggested a direct concentration effect from inhaled inorganic arsenic, whereby the excess relative risk for a fixed cumulative exposure was greater when delivered at a higher concentration and shorter duration than when delivered at a lower concentration and longer duration.

Uncertainties in biologically-based modeling of formaldehyde-induced respiratory cancer risk: identification of key issues.

In a series of articles and a health-risk assessment report, scientists at the CIIT Hamner Institutes developed a model (CIIT model) for estimating respiratory cancer risk due to inhaled formaldehyde within a conceptual framework incorporating extensive mechanistic information and advanced computational methods at the toxicokinetic and toxicodynamic levels. Several regulatory bodies have utilized predictions from this model; on the other hand, upon detailed evaluation the California EPA has decided against doing so. In this article, we study the CIIT model to identify key biological and statistical uncertainties that need careful evaluation if such two-stage clonal expansion models are to be used for extrapolation of cancer risk from animal bioassays to human exposure. Broadly, these issues pertain to the use and interpretation of experimental labeling index and tumor data, the evaluation and biological interpretation of estimated parameters, and uncertainties in model specification, in particular that of initiated cells. We also identify key uncertainties in the scale-up of the CIIT model to humans, focusing on assumptions underlying model parameters for cell replication rates and formaldehyde-induced mutation. We discuss uncertainties in identifying parameter values in the model used to estimate and extrapolate DNA protein cross-link levels. The authors of the CIIT modeling endeavor characterized their human risk estimates as "conservative in the face of modeling uncertainties." The uncertainties discussed in this article indicate that such a claim is premature.

Mortality among Coast Guard Shipyard workers: A retrospective cohort study of specific exposures.

In a previous analysis of a cohort of shipyard workers, we found excess mortality from all causes, lung cancer, and mesothelioma for longer work durations and in specific occupations. Here, we expand the previous analyses by evaluating mortality associated with 5 chemical exposures: asbestos, solvents, lead, oils/greases, and wood dust. Data were gathered retrospectively for 4,702 workers employed at the Coast Guard Shipyard, Baltimore, MD (1950-1964). The cohort was traced through 2001 for vital status. Associations between mortality and these 5 exposures were calculated via standardized mortality ratios (SMRs). We found all 5 substances to be independently associated with mortality from mesothelioma, cancer of the respiratory system, and lung cancer. Findings from efforts to evaluate solvents, lead, oils/greases, and wood dust in isolation of asbestos suggested that the excesses from these other exposures may be due to residual confounding from asbestos exposure.

Respiratory cancer mortality and incidence in an updated cohort of Canadian nickel production workers.

Respiratory cancer mortality and incidence were examined in an updated cohort of >56,000 Canadian nickel mining and refining workers. There was little evidence to suggest increased lung cancer risk in workers who had no experience in high-risk sintering operations that were closed by 1972, apart from that which would be expected from probable increased smoking prevalence relative to the comparison population. There was no substantive evidence of increased laryngeal cancer risk in the cohort, nor was there evidence of increased pharyngeal cancer risk in nonsinter workers. Nasal cancer incidence was elevated in nonsinter workers, but excess risks appeared to be confined to those hired prior to 1960. These findings lead us to tentatively conclude that occupationally-related respiratory risks in workers hired over the past 45 years are either very low or nonexistent.

Respiratory cancer risks among workers with glutaraldehyde exposure.

OBJECTIVE: Glutaraldehyde is a substance that represents a substantial portion of the human exposure to aldehydes in medicine and industry. Other aldehydes such as formaldehyde have been associated with increased cancer rates of the upper respiratory tract and leukemia. Our study is the only one, to our knowledge, to examine cancer rates among exposed glutaraldehyde workers. METHODS: In an extended follow up using death certificates, we calculated standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) for three cumulative exposure categories of glutaraldehyde. There were 99,730 person-years of observation among unexposed workers, 2934 person-years in the lower exposure category, < 0-100.0 parts per billion (ppb)-years, and 2805 person-years in the higher exposure category of 100.0+ ppb-years. RESULTS: For all respiratory cancers for these exposure categories, the SMRs were 0.9 (95% CI = 0.7-1.1), 1.0 (95% CI = 0.2-3.0), and 0.3 (95% CI = 0.0-1.5). No increasing trend of SMR with increasing exposure is observed for any cause of death examined. We observed no cancers of the nasal cavity and sinus (0.03 expected), nasopharynx (0.02 expected), or leukemia (0.6 expected) among all glutaraldehyde-exposed workers. CONCLUSIONS: Although our study findings should be tempered by the small size and the potentially low prevalence of smoking among glutaraldehyde workers, we found no increased rates of respiratory tract cancer or leukemia related to glutaraldehyde exposure.

Transplacental effects of diethylnitrosamine in Syrian hamsters as related to different days of administration during pregnancy.

Female Syrian hamsters were given a single sc dose of 45 mg diethylnitrosamine (DEN)/kg body weight on 1 of the 15 days of pregnancy. In the offspring of females treated on 1 of the first 11 days of pregnancy, no respiratory tract tumors were found. The offspring of mothers given DEN on 1 of the last 4 days (12-15) of pregnancy developed respiratory tract neoplasms at a rate of up to 95%. A lower incidence of tumors in other organs seemed independent of the day of DEN treatment.