Best estimate of the magnitude of mortality due to occupational exposure to hazardous substances

OBJECTIVES: With a proportionate attributable risk approach, to estimate the magnitude of premature mortality induced by exposure to hazardous substances in the Australian workforce. METHODS: Estimates of the magnitude of mortality induced by exposure to hazardous substances in the Australian work-force were calculated by the proportionate attributable risk approach after careful consideration of options for methodological refinements. The main data sources used were unit mortality datasets (individual deidentified death records), and tabulations when these were unavailable. RESULTS: The estimated number of deaths that occurred in Australia each year from occupational exposure to hazardous substances was 2290; 78% of these were men. The rate of mortality attributable to occupational exposure to hazardous substances was three to four times greater in male workers than in female workers. Male (productive) person-years of life lost (PYLL) were generally eight times higher than female PYLL. Cancer was the prime cause of death, followed by renal, cardiovascular, neurological, and chronic respiratory disease. Acute toxic episodes accounted for a small proportion of mortality but yielded a much larger proportion of PYLL, reflecting the relatively young ages of those who experienced fatal effects. CONCLUSIONS: Although national estimates of the proportions of mortality attributable to occupational exposure to hazardous substances seemed to be validly derived, uncertainties remain associated with the lack of an empirical basis for derivation of proportionate risk fractions used in the calculations. The finding of an appreciable burden of mortality that is attributable to past occupational exposure to hazardous substances emphasises the necessity for occupational health and safety authorities to measure and reduce worksite exposures. There is also an incentive to encourage the construction of appropriately designed cohort studies across industries and occupational groupings so that, ultimately, risk estimates may be directly calculated and applied to total workforce data for the definitive estimation of the magnitude of harm induced by occupational exposure to hazardous substances.     

Evaluation of occupational radiation exposure in veterinary radiographic diagnosis (a review)

A short review is given about fundamental dose units, the carcinogenic risk coefficients of ionizing radiation, the radiation exposure and potential radiation effects in the veterinary practice. The fundamentals of radiation protection comprise, inter alia, a modern and efficient X-ray and protection equipment, radiation safety training, radiation detection devices and, especially, restricting the size of the primary beam.     

Bundle-branch block and in-hospital mortality in acute myocardial infarction. National Registry of Myocardial Infarction 2 Investigators

BACKGROUND: Left bundle-branch block (BBB) is considered an important predictor of poor outcome in patients with acute myocardial infarction, but the consequences of right BBB are not well understood. OBJECTIVES: To 1) estimate the prevalence of left and right BBB in patients with myocardial infarction; 2) compare the clinical characteristics of and treatments received by patients with left, right, or no BBB; and 3) determine the independent association of left BBB and right BBB with in-hospital death. DESIGN: Retrospective cohort study. SETTING: Multicenter registry of 1571 U.S. hospitals. PATIENTS: 297,832 patients with acute myocardial infarction who had left, right, or no BBB on initial electrocardiography. MEASUREMENTS: Presence and type of BBB, clinical characteristics of patients, therapies given, and in-hospital death. RESULTS: Patients with left BBB (n = 19,967; 6.7%) or right BBB (n = 18,354; 6.2%) were older and had more comorbid illness and congestive heart failure than patients with no BBB. Among patients for whom thrombolytic therapy was clearly indicated, fewer patients with left or right BBB (16.6% and 32.0%, respectively) than patients with no BBB (66.5%) received this therapy (P < 0.001). Fewer patients with left or right BBB (60.6% and 67.3%, respectively) than patients with no BBB (75.6%) received aspirin within the first 24 hours (P < 0.001), and fewer patients with left or right BBB (23.9% and 31.8%, respectively) than patients with no BBB (40.4%) received beta-blockers within the first 24 hours (P < 0.001). Unadjusted in-hospital mortality rates were almost twice as high for patients with left or right BBB (22.6% and 23.0%, respectively) as for patients with no BBB (13.1%) (P < 0.001). Compared with no BBB and no ST-segment elevation, left BBB was associated with a 34% increase (odds ratio, 1.34 [95% CI, 1.28 to 1.39]) and right BBB was associated with a 64% increase (odds ratio, 1.64 [CI, 1.57 to 1.71]) in the risk for in-hospital death, after adjustment for potential confounders. CONCLUSIONS: In patients with acute myocardial infarction, prevalences of right and left BBB are similar. Patients with BBB have more comorbid conditions, are less likely to receive therapy, and have an increased risk for in-hospital death compared with patients with no BBB. Compared with left BBB, right BBB seems to be a stronger independent predictor of in-hospital death.     

Estimate of mortality from occupational cancer and of carcinogen exposure in the workplace in Spain in the 90's

We estimated the number of cancers attributed to occupational exposures in Spain, and examined the prevalence of carcinogenic exposures in the workplace. We used population, labour, mortality and morbidity statistics and applied an approach used by Doll and Peto for the population of the USA. In men 6% and in women 1% of all cancers can be attributed to occupational exposures. Lung cancer accounts for 62% of all occupational cancers. About 402,346 men and women are employed in industries or occupations entailing a well recognised carcinogenic risk. In addition, a large but unquantifiable number of workers are employed in various other occupations and industries where exposure to carcinogenic chemical or physical agents may occur. The identification and control of carcinogenic exposures may lead to the prevention of a considerable number of cancers in the Spanish adult population.     

Registry of experimental cancers of the National Cancer Institute

This report describes the organization and functions of the Registry of Experimental Cancers and gives the chronology of events that led to its establishment. Currently 21,500 accessions have been coded; the vast majority are spontaneous and induced cancers, chiefly of rodents, and also a wide variety of nonneoplastic diseases. Accessions are accepted from contributors working in laboratories in this country and abroad. The material is available for study by responsible scientists, and a limited number of study sets is available for loan on request.     

A comparative analysis of the existing standards for exposure to ultraviolet radiation

Medical imaging technology is rapidly expanding and the role of each modality is being redefined constantly. PET has been around since the early sixties and gained clinical acceptance in oncology only after an extreme number of scientific publications. Although PET has the unique ability to image biochemical processes in vivo, this ability is not fully used as a clinical imaging tool. In this overview, the role of PET in relation to other tumor imaging modalities will be discussed and the reported results in the literature will be reviewed. In predicting the future of PET, technical improvements of other imaging modalities need to be dealt with. The fundamental physical principles for image formation with computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), photon-emission tomography (PET), and single photon emission CT (SPECT) will not change. The potential variety of radiopharmaceuticals which may be developed is unlimited, however, and this provides nuclear imaging techniques with a significant advantage and adaptive features for future biologic imaging. The current applications of PET in oncology have been in characterizing tumor lesions, differentiating recurrent disease from treatment effects, staging tumors, evaluating the extent of disease, and monitoring therapy. The future developments in medicine may use the unique capabilities of PET not only in diagnostic imaging but also in molecular medicine and genetics. The articles discussed in this review were selected from a literature search covering the last 3 years, and in which comparisons of PET with conventional imaging were addressed specifically. PET studies with the glucose analogue fluorine-18-labeled deoxyglucose (FDG) have shown the ability of detecting tumor foci in a variety of histological neoplasms such as thyroid cancer, breast cancer, lymphoma, lung cancer, head and neck carcinoma, colorectal cancer, ovarian carcinoma, and musculoskeletal tumors. Also, the contribution of the whole body PET (WBPET) imaging technique in diagnosis will be discussed. In the current health care environment, a successful imaging technology must not only change medical management but also demonstrate that those changes improve patient outcome.     

National Transplantation Pregnancy Registry: analysis of pregnancy outcomes in female liver transplant recipients

Outcomes from 48 pregnancies in 34 female liver transplant recipients were analyzed. Data were collected via interviews, questionnaires, and hospital records. All recipients were treated with cyclosporine-based immunosuppression except 2 patients treated with FK506 and 2 treated with no immunosuppression. The age at conception was 26.1 +/- 5.9 years (mean +/- SD) with a transplant interval (time from transplantation to conception) of 2.9 +/- 2.5 years. There were 49 outcomes (1 set of twins): miscarriage 9 (18%), therapeutic abortion 4 (8%), and live birth 36 (74%). No stillbirths or ectopic pregnancies were reported. Of the 36 live births, the gestational age was 36.9 +/- 3.5 weeks, the birthweight was 2,604 +/- 698 grams, 39% were premature (< 37 weeks), and 31% had low birthweight (< 2,500 grams). No birth defects or neonatal deaths (< 28 days) were reported. The newborn complication rate was 17% (n = 6), 5% in premature infants. The incidence of drug-treated hypertension was 46%; pre-eclampsia 21%; infectious complications 26%; and Caesarean section 47%. Recipients with hypertension had a higher proportion of premature infants (71%) than normotensive patients (38%) (P = .04 by Fisher's exact test). Acute rejection was diagnosed in 6 pregnancies, 2 of which were ended by therapeutic abortion. Four recipients who continued their pregnancies were treated with increased immunosuppression for rejection, and all delivered livebirths. There were two grafts lost within 6 months of pregnancy. The only maternal death occurred in a patient who required retransplantation for recurrent C hepatitis 3 months afte therapeutic abortion and died 6 months later. The other recipient with graft loss was successfully retransplanted for chronic rejection 6 months after delivery. We draw the following conclusions: (1) female liver transplant recipients can safely undergo pregnancy, although there is a high rate of premature and low birthweight infants; (2) pregnancies in this population should be considered high-risk and require close monitoring of liver function; and (3) altered graft function during pregnancy should be thoroughly investigated.     

Industry''s perception and use of occupational exposure limits

OBJECTIVE: To examine posttraumatic stress disorder (PTSD) in mothers of survivors of childhood cancer. Comorbidity of anxiety and depressive disorders, prevalence of subclinical PTSD, and the utility of a self-report measure as a screening instrument for PTSD were also investigated. METHOD: Mothers (n = 65) completed a questionnaire self-report PTSD checklist (PCL-C). Mothers were administered several modules of the SCID: nonpatient edition by telephone, including the PTSD, Generalized Anxiety, and Major Depressive Disorder modules. RESULTS: We diagnosed 6.2% of the sample with current PTSD. An additional 20% had subclinical PTSD. One of four mothers with PTSD diagnoses had a comorbid diagnosis of an anxiety and depressive disorder. The PCL-C evidenced diagnostic utility as a screening instrument. However, a moderate number of false-positives would result if the recommended cut-off on the instrument was used. CONCLUSIONS: The PCL-C had diagnostic utility in screening mothers of childhood cancer survivors. The presence of comorbid diagnoses such as anxiety and depression should be examined.     

Renal effects of environmental and occupational lead exposure

Environmental and industrial lead exposures continue to pose major public health problems in children and in adults. Acute exposure to high concentrations of lead can result in proximal tubular damage with characteristic histologic features and manifested by glycosuria and aminoaciduria. Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout. A high incidence of nephropathy was reported during the early part of this century from Queensland, Australia, in persons with a history of childhood lead poisoning. No such sequela has been found in studies of three cohorts of lead-poisoned children from the United States. Studies in individuals with low-level lead exposure have shown a correlation between blood lead levels and serum creatinine or creatinine clearance. Chronic low-level exposure to lead is also associated with increased urinary excretion of low molecular weight proteins and lysosomal enzymes. The relationship between renal dysfunction detected by these sensitive tests and the future development of chronic renal disease remains uncertain. Epidemiologic studies have shown an association between blood lead levels and blood pressure, and hypertension is a cardinal feature of lead nephropathy. Evidence for increased body lead burden is a prerequisite for the diagnosis of lead nephropathy. Blood lead levels are a poor indicator of body lead burden and reflect recent exposure. The EDTA lead mobilization test has been used extensively in the past to assess body lead burden. It is now replaced by the less invasive in vivo X-ray fluorescence for determination of bone lead content.     

A mathematical analysis of the mortality kinetics of Drosophila melanogaster exposed to gamma radiation

Being interested in factors stabilizing neurotubules (NTs) in situ, we decided to immerse short segments of fresh rat peripheral nerves in buffered solutions containing ZnCl2 in final concentrations up to 10-2 m prior to fixation with buffered osmium or glutaraldehyde, both containing ZnCl2. Zinc treatment resulted in a remarkable structural preservation of NTs after fixation with osmium, though they are not preserved by osmium fixation alone. Cross sections of myelinated nerve fibres show NTs arranged predominantly in compact groups. Within the groups NTs are surrounded or embedded in an electron dense fine granular material. The occurrence of incomplete C-shaped NTs and NT-like densities can be seen. NTs exhibit relatively constant distances and sometimes geometric patterns of arrangement. A lot of intertubule cross bridges and NTs with arms could be observed. In longitudinal section the bridge and arm spacing is seen to be periodic along the tubule axis at about 500 A. Zinc treatment of nerves fixed in glutaraldehyde resulted in the same ultrastructural alterations described above. The resistance of zinc-stabilized NTs to degradation by osmium and the ultrastructural changes induced by zinc are discussed. The results suggest that in the presence of zinc ions osmium-labile NTs are transformed--by disassembly and reassembly--to osmium-stabile microtubules that are not identical with preexisting ones.     

Beneficial effects of sun exposure on cancer mortality

For more than 50 years, there has been documentation in the medical literature suggesting that regular sun exposure is associated with substantial decreases in death rates from certain cancers and a decrease in overall cancer death rates. Recent research suggests that this is a causal relationship that acts through the body's vitamin D metabolic pathways. The studies reviewed here show that (a) sunlight activation is our most effective source of vitamin D; (b) regular sunlight/vitamin D "intake" inhibits growth of breast and colon cancer cells and is associated with substantial decreases in death rates from these cancers; (c) metabolites of vitamin D have induced leukemia and lymphoma cells to differentiate, prolonged survival of leukemic mice, and produced complete and partial clinical responses in lymphoma patients having high vitamin D metabolite receptor levels in tumor tissue; (d) sunlight has a paradoxical relationship with melanoma, in that severe sunburning initiates melanoma whereas long-term regular sun exposure inhibits melanoma; (e) frequent regular sun exposure acts to cause cancers that have a 0.3% death rate with 2,000 U.S. fatalities per year and acts to prevent cancers that have death rates from 20-65% with 138,000 U.S. fatalities per year; (f) there is support in the medical literature to suggest that the 17% increase in breast cancer incidence during the 1991-1992 year may be the result of the past decade of pervasive anti-sun advisories from respected authorities, coinciding with effective sunscreen availability; and (g) trends in the epidemiological literature suggest that approximately 30,000 U.S. cancer deaths yearly would be averted by the widespread public adoption of regular, moderate sunning.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidemiologic methods for evaluating the effects of occupational exposure on pregnancy outcome

Methodological problems of epidemiological studies of the effect of harmful factors present in the working environment on the reproduction and development of the progeny were discussed. Basic types of epidemiological studies such as retrospective and prospective cohort studies, cross-sectional and case-control studies were presented. Issues pertaining to the measurement bias and its sources in individual types of studies were raised. An appropriate selection of measures illustrating disturbances in the reproduction and development of the progeny was considered as well as adapted definitions of those measures and their correct classification. ahe methodology of an appropriate assessment of exposure to harmful factors in the working environment was also discussed.     

Exposure-response analysis of risk of respiratory disease associated with occupational exposure to chrysotile asbestos

OBJECTIVES: To evaluate alternative models and estimate risk of mortality from lung cancer and asbestosis after occupational exposure to chrysotile asbestos. METHODS: Data were used from a recent update of a cohort mortality study of workers in a South Carolina textile factory. Alternative exposure-response models were evaluated with Poisson regression. A model designed to evaluate evidence of a threshold response was also fitted. Lifetime risks of lung cancer and asbestosis were estimated with an actuarial approach that accounts for competing causes of death. RESULTS: A highly significant exposure-response relation was found for both lung cancer and asbestosis. The exposure-response relation for lung cancer seemed to be linear on a multiplicative scale, which is consistent with previous analyses of lung cancer and exposure to asbestos. In contrast, the exposure-response relation for asbestosis seemed to be nonlinear on a multiplicative scale in this analysis. There was no significant evidence for a threshold in models of either the lung cancer or asbestosis. The excess lifetime risk for white men exposed for 45 years at the recently revised OSHA standard of 0.1 fibre/ml was predicted to be about 5/1000 for lung cancer, and 2/1000 for asbestosis. CONCLUSIONS: This study confirms the findings from previous investigations of a strong exposure-response relation between exposure to chrysotile asbestos and mortality from lung cancer, and asbestosis. The risk estimates for lung cancer derived from this analysis are higher than those derived from other populations exposed to chrysotile asbestos. Possible reasons for this discrepancy are discussed.     

首届全国环境与生态心理学大会会议综述

2010年10月,首届全国环境与生态心理学大会在北京林业大学举办.会议以环境与人类心理为主题,开展了生态心理学研究进展、环境认知与心理健康、发展教育心理学的生态观研究、心理学对环境危机问题的思考、交叉学科的环境与生态心理学研究等专题讨论.同时,会议讨论了环境与生态心理学未来的发展趋势.本次大会是我国首次召开的环境与生态心理学大会,会议的召开在我国环境与生态心理学发展方面具有里程碑意义.     

Human exposure assessment and the National Toxicology Program

The National Institute of Environmental Health Sciences/National Toxicology Program (NIEHS/NTP) is developing a new interagency initiative in exposure assessment. This initiative involves the NIEHS, the Centers for Disease Control and Prevention through its National Center for Environmental Health, the National Institute for Occupational Safety and Health, the EPA, and other participating institutes and agencies of the NTP. This initiative will benefit public health and priority setting in a number of ways. First, as discussed above, it will strengthen the scientific foundation for risk assessments by the development of more credible exposure/response relationships in people by improving cross-species extrapolation, the development of biologically based dose-response models, and the identification of sensitive subpopulations and for "margin of exposure" based estimates of risk. Second, it will provide the kind of information necessary for deciding which chemicals should be studied with the limited resources available for toxicological testing. For example, there are 85,000 chemicals in commerce today, and the NTP can only provide toxicological evaluations on 10-20 per year. Third, we would use the information obtained from the exposure initiative to focus our research on mixtures that are actually present in people's bodies. Fourth, we would obtain information on the kinds and amount of chemicals in children and other potentially sensitive subpopulations. Determinations of whether additional safety factors need to be applied to children must rest, in part, upon comparative exposure analyses between children and adults. Fifth, this initiative, taken together with the environmental genome initiative, will provide the science base essential for meaningful studies on gene/environment interactions, particularly for strengthening the evaluation of epidemiology studies. Sixth, efficacy of public health policies aimed at reducing human exposure to chemical agents could be evaluated in a more meaningful way if body burden data were available over time, including remediation around Superfund sites and efforts to achieve environmental justice. The exposure assessment initiative is needed to address public health needs. It is feasible because of recent advances in analytical technology and molecular biology, and it is an example of how different agencies can work together to better fulfill their respective missions.     

Report of a panel on the relationship between public exposure to pesticides and cancer. Ad Hoc Panel on Pesticides and Cancer. National Cancer Institute of Canada

BACKGROUND: Pesticides, which by their nature are biologically active compounds, continue to raise public concern regarding their possible role as important etiologic agents in the development of human cancer. METHODS: To examine this potential role, the National Cancer Institute of Canada convened an Ad Hoc Panel on Pesticides and Cancer to examine the possible contribution of pesticide exposure, particularly in the general population, to the development of human cancer. RESULTS: The Panel focused primarily on exposure in the general population and reviewed a range of studies that addressed issues related to dietary exposure as well as incidental home and garden uses. In addition, the Panel examined the regulatory framework that exists to safeguard the public from potentially carcinogenic pesticides and also reviewed some potential benefits of pesticide use, including the availability of an abundant and low cost supply of fresh fruits and vegetables as an important strategy in the overall mitigation of cancer risk. CONCLUSIONS: The Panel concluded that it was not aware of any definitive evidence to suggest that synthetic pesticides contribute significantly to overall cancer mortality. The Panel also concluded that it did not believe that any increased intake of pesticide residues associated with increased intake of fruits and vegetables poses any increased risk of cancer. The Panel further concluded, among other things, that tobacco use continues to be the most important preventable cause of cancer and premature mortality and thus is an appropriate focus for cancer control strategy.