ObjectivesRadon is carcinogenic, but more studies are needed to understand relationships with lung cancer and extrathoracic cancers at low exposures. There are few studies evaluating associations ...with cancer incidence or assessing the modifying effects of smoking.MethodsWe conducted a case–cohort study with 16 434 underground uranium miners in the Czech Republic with cancer incidence follow-up 1977–1996. Associations between radon exposure and lung cancer, and extrathoracic cancer, were estimated with linear excess relative rate (ERR) models. We examined potential modifying effects of smoking, time since exposure and exposure rate.ResultsUnder a simple ERR model, assuming a 5-year exposure lag, the estimated ERR of lung cancer per 100 working level months (WLM) was 0.54 (95% CI 0.33 to 0.83) and the estimated ERR of extrathoracic cancer per 100 WLM was 0.07 (95% CI −0.17 to 0.72). Most lung cancer cases were observed among smokers (82%), and the estimated ERR of lung cancer per 100 WLM was larger among smokers (ERR/100 WLM=1.35; 95% CI 0.84 to 2.15) than among never smokers (ERR/100 WLM=0.12; 95% CI −0.05 to 0.49). Among smokers, the estimated ERR of lung cancer per 100 WLM decreased with time since exposure from 3.07 (95% CI −0.04 to 10.32) in the period 5–14 years after exposure to 1.05 (95% CI 0.49 to 1.87) in the period 25+ years after exposure.ConclusionsWe observed positive associations between cumulative radon exposure and lung cancer, consistent with prior studies. We observed a positive association between cumulative radon exposure and extrathoracic cancers, although the estimates were small. There was evidence that the association between radon and lung cancer was modified by smoking in a multiplicative or super-multiplicative fashion.
Objective: Toxicology studies suggest that carbon nanotube (CNT) exposures may cause adverse pulmonary effects. This study identified all US engineered carbonaceous nanomaterial (ECN) manufacturers, ...determined workforce size and growth, and characterized the materials produced to determine the feasibility of occupational ECN exposure studies. Methods: Eligible companies were identified; information was assembled on the companies and nanomaterials they produced; and the workforce size, location, and growth were estimated. Results: Sixty-one companies manufacturing ECN in the United States were identified. These companies employed at least 620 workers; workforce growth was projected at 15% to 17% annually. Most companies produced or used CNT. Half the eligible companies provided information about material dimensions, quantities, synthesis methods, and worker exposure reduction strategies. Conclusions: Industrywide exposure assessment studies appear feasible; however, cohort studies are likely infeasible because of the small, scattered workforce.
OBJECTIVE:Capitalizing on phenomena at the nanoscale may present great benefits to society. Nevertheless, until the hazards and risks of engineered nanoparticles are determined, the technological ...products and advances of nanotechnology may be impeded by the societal concerns. Although animal data provide the necessary first step in hazard and risk assessment, ultimately epidemiological studies will be required, especially studies of workers exposed to engineered nanoparticles. It may be too soon to conduct informative epidemiological studies but it is now appropriate to identify issues that will be pertinent and prepare strategies to address them.
METHODS:The published scientific literature on incidental and engineered nanoparticles and air pollution were reviewed to identify issues in the conduct of epidemiological studies of workers exposed to engineered nanoparticles.
RESULTS:Twelve important issues were identified—the most critical pertaining to particle heterogeneity, temporal factors, exposure characterization, disease endpoints, and identification of the study population.
CONCLUSION:Consideration of these issues provides the foundation for initiating epidemiologic research on workers exposed to engineered nanoparticles.
IntroductionStudies of nuclear workers provide insights into the health effects of ionizing radiation at levels relevant to contemporary workers and the general public. We evaluated the association ...between penetrating ionizing radiation exposure and cancer mortality subtypes in a large pooled cohort of US nuclear workers. Follow-up was extended an additional decade to improve power and examine cancers with longer latency.Materials and MethodsThe pooled cohort includes 101,363 workers from five US Department of Energy and Department of Defense nuclear facilities, followed for causes of death between 1944 and 2016. Workers were individually monitored for ionizing radiation exposure with the use of personal dosimeter badges. The association between cumulative external penetrating ionizing radiation exposure and cancer subtypes were modeled as the excess relative rate per Sievert (ERR Sv-1) using Cox regression.ResultsThere were 13,568 cancer deaths during follow-up. We observed positive associations between ionizing radiation exposure and all solid cancer mortality (ERR Sv-1=0.19; 95%CI: -0.10, 0.52), and all lymphatic and hematopoietic cancers (ERR Sv-1=2.10; 95%CI: 0.97, 3.48). These associations were stronger among a contemporary sub cohort of workers first hired 1960 or later for both solid cancer (ERR Sv-1= 2.23; 95% CI: 1.13, 3.49) and all lymphatic and hematopoietic cancers (ERR Sv-1= 6.26; 95%CI: 2.86, 10.83). Additionally, we observed positive associations for several site specific lymphatic and hematopoietic cancer types, as well as lung cancer. In some instances, we observed modification by time since exposure and age at exposure.ConclusionsThis analysis confirms the association between low dose, low dose-rate radiation and leukemias, and strengthens the evidence base supporting the radiogenic nature of some solid cancers. The extended follow-up, individual dosimetry, and precise estimates provided by this large pooled analysis can better inform current radiological protection models.
ObjectivesUranium miners in Příbram, Czech Republic were exposed to low and moderate levels of radon gas and other hazards. It is unknown whether these hazards increase the risk of mortality or ...cancer incidence when compared with the general Czech population.MethodsA cohort of 16 434 male underground miners employed underground for at least 1 year between 1946 and 1976, and alive and residing in the Czech Republic in 1977, were followed for mortality and cancer incidence through 1992. We compared observed deaths and cancer incidence to expectation based on Czech rates. Standardised mortality ratios (SMRs), standardised incidence ratios (SIRs) and causal mortality ratios were calculated.ResultsUnderground workers in the Příbram mines had higher rates of death than expected due to all causes (SMR=1.23, 95% CI 1.20 to 1.27), all cancers (SMR=1.52, 95% CI 1.44 to 1.60), lung cancer (SMR=2.12, 95% CI 1.96 to 2.28) and extrathoracic cancer (SMR=1.41, 95% CI 1.15 to 1.77). Similar excess was observed in cancer incidence analyses, with the addition of stomach cancer (SIR=1.37, 95% CI 1.11 to 1.63), liver cancer (SIR=1.70, 95% CI 1.16 to 2.25) and rectal cancer (SIR=1.41, 95% CI 1.16 to 1.66). The SIR was elevated for all leukaemias (SIR=1.51, 95% CI 1.08 to 2.07) and for lymphatic and haematopoietic cancers combined (SIR=1.31, 95% CI 1.05 to 1.61), but results for specific subtypes were imprecise. Deaths due to hazardous mining conditions resulted in 0.33 person-years of life lost per miner.ConclusionsOccupational exposure to the Příbram mines resulted in excess cancers at several sites, including sites previously linked to radon and uranium exposure. Incidence analyses showed relative excess of several additional cancer subtypes.
Because of their antibacterial and antifungal properties, gentian violet and malachite green have had various medical, veterinary, and aquaculture applications, including the treatment of livestock, ...animal feed, ornamental fish, and farmed fish and shellfish. In B6C3F1 mice exposed via the diet, gentian violet caused hepatocellular carcinoma in males and females, and histiocytic sarcoma of the bladder, ovary, uterus, and vagina in females.3 In F344 rats exposed in utero, followed by lactational and then dietary exposure, gentian violet caused follicular cell adenocarcinoma of the thyroid gland in males and females, and mononuclear cell leukaemia in females.4 In orally dosed rats, malachite green is excreted primarily in the faeces. After dietary exposure, leucomalachite green caused follicular cell adenoma or carcinoma (combined) of the thyroid gland in male F344 rats, adenoma or carcinoma (combined) of the mammary gland in female F344 rats, and hepatocellular adenoma or carcinoma (combined) in female B6C3F1 mice.5,6 CI Direct Blue 218 is a copper-chelated dimethoxybenzidine-based azo dye used for cellulose, acetate, nylon, silk, wool, tissue, fine papers, and textile goods.
Abstract
This commentary is written in response to a recent commentary in Carcinogenesis that provides several viewpoints on the International Agency for Research on Cancer’s (IARC) Monographs ...program on cancer hazard identification. This commentary offers an alternative viewpoint of the role of cancer hazard identification derived from cancer epidemiology studies in risk characterization, as well as clarification on the previous commentary’s interpretation of the purpose of the Monographs and other programs of cancer hazard identification and how IARC communicates the findings of the Monographs.
This commentary offers an alternative viewpoint to a recent commentary in Carcinogenesisregarding the International Agency for Research on Cancer’s (IARC) Monographsprogram on cancer hazard identification.
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Graphical Abstract
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