Track topics on Twitter Track topics that are important to you
NIOSH/NCI (National Institute of Occupational Safety and Health and National Cancer Institute) developed exposure estimates for respirable elemental carbon (REC) as a surrogate for exposure to diesel exhaust (DE) for different jobs in eight underground mines by year beginning in the 1940s-1960s when diesel equipment was first introduced into these mines. These estimates played a key role in subsequent epidemiological analyses of the potential relationship between exposure to DE and lung cancer conducted in these mines. We report here on a reanalysis of some of the data from this exposure assessment. Because samples of REC were limited primarily to 1998-2001, NIOSH/NCI used carbon monoxide (CO) as a surrogate for REC. In addition, because CO samples were limited, particularly in the earlier years, they used the ratio of diesel horsepower (HP) to the mine air exhaust rate as a surrogate for CO. There are considerable uncertainties connected with each of these surrogate-based steps. The estimates of HP appear to involve considerable uncertainty, although we had no data upon which to evaluate the magnitude of this uncertainty. A sizable percentage (45%) of the CO samples used in the HP to CO model was below the detection limit which required NIOSH/NCI to assign CO values to these samples. In their preferred REC estimates, NIOSH/NCI assumed a linear relation between C0 and REC, although they provided no credible support for that assumption. Their assumption of a stable relationship between HP and CO also is questionable, and our reanalysis found a statistically significant relationship in only one-half of the mines. We re-estimated yearly REC exposures mainly using NIOSH/NCI methods but with some important differences: (i) rather than simply assuming a linear relationship, we used data from the mines to estimate the CO-REC relationship; (ii) we used a different method for assigning values to nondetect CO measurements; and (iii) we took account of statistical uncertainty to estimate bounds for REC exposures. This exercise yielded significantly different exposure estimates than estimated by NIOSH/NCI. However, this analysis did not incorporate the full range of uncertainty in REC exposures because of additional uncertainties in the assumptions underlying the modeling and in the underlying data (e.g. HP and mine exhaust rates). Estimating historical exposures in a cohort is generally a very difficult undertaking. However, this should not prevent one from recognizing the uncertainty in the resulting estimates in any use made of them.
ENVIRON International Corporation , USA.
This article was published in the following journal.
Name: Critical reviews in toxicology
Diesel emissions are the main source of air pollution in urban areas, and diesel exposure is linked with substantial adverse health effects. In vitro diesel exposure models are considered a suitable t...
Exposure to diesel engine exhaust has been linked to increased cancer risk and cardiopulmonary diseases. Diesel exhaust is a complex mixture of chemical substances, including a particulate fraction ma...
With emerging evidence that diesel exhaust exposure poses distinct risks to human health, the need for fine-scale models of diesel exhaust pollutants is growing. We modeled the spatial distribution of...
Etheno-DNA adducts are biomarkers for assessing oxidative stress. In this study, the aim was to detect the level of etheno-DNA adducts and explore the relationship between the etheno-DNA adducts and g...
The aim of this study was to evaluate oxidative stress markers in human conjunctival epithelial cells (IOBA-NHC) exposed to diesel exhaust particles (DEP).
Diesel exhaust has been classified as a probable carcinogen by the International Agency for Research on Cancer and as a potential carcinogen by the National Institute for Occupational Safe...
Exposure to combustion-derived fine particulate air pollution is associated with cardiovascular mortality and morbidity. In previous studies, exposure to diesel exhaust (a major constituen...
Acute exposure to diesel exhaust under normal city conditions leads to a worsening of symptoms of asthma, with reduction in lung function in asthmatic nonsmoking adults, dependent on the e...
The purpose of this study is to determine whether exposure to diesel exhaust (air pollution) has a functional impact on patients with stable angina pectoris.
Allergic rhinitis (AR) is a condition that exists when an individual with a specific allergy reacts to that allergen resulting in a runny and/or stuffy nose, postnasal drip, and possible s...
Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.
The science concerned with the benefit and risk of drugs used in populations and the analysis of the outcomes of drug therapies. Pharmacoepidemiologic data come from both clinical trials and epidemiological studies with emphasis on methods for the detection and evaluation of drug-related adverse effects, assessment of risk vs benefit ratios in drug therapy, patterns of drug utilization, the cost-effectiveness of specific drugs, methodology of postmarketing surveillance, and the relation between pharmacoepidemiology and the formulation and interpretation of regulatory guidelines. (Pharmacoepidemiol Drug Saf 1992;1(1); J Pharmacoepidemiol 1990;1(1))
Evaluation procedures that focus on both the outcome or status (OUTCOMES ASSESSMENT) of the patient at the end of an episode of care - presence of symptoms, level of activity, and mortality; and the process (ASSESSMENT, PROCESS) - what is done for the patient diagnostically and therapeutically.
Studies designed to assess the efficacy of programs. They may include the evaluation of cost-effectiveness, the extent to which objectives are met, or impact.
Evaluation and measurement of nutritional variables in order to assess the level of nutrition or the NUTRITIONAL STATUS of the individual. NUTRITION SURVEYS may be used in making the assessment.
Lung cancer is the uncontrolled cell growth in tissues of the lung. Originating in the lungs, this growth may invade adjacent tissues and infiltrate beyond the lungs. Lung cancer, the most common cause of cancer-related death in men and women, is respons...
Within medicine, nutrition (the study of food and the effect of its components on the body) has many different roles. Appropriate nutrition can help prevent certain diseases, or treat others. In critically ill patients, artificial feeding by tubes need t...
Bladder Cancer Brain Cancer Breast Cancer Cancer Cervical Cancer Colorectal Head & Neck Cancers Hodgkin Lymphoma Leukemia Lung Cancer Melanoma Myeloma Ovarian Cancer Pancreatic Cancer ...