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Biomedical subjects

P A Schulte

Publications and source records attributed to P A Schulte.

At least 19 recordsLinked to original sources
PubMed2006

The Upper Midwest Health Study: a case-control study of primary intracranial gliomas in farm and rural residents.

Since several studies indicated that farmers and agricultural workers had an excess risk of brain cancer, the National Institute for Occupational Safety and Health initiated the Upper Midwest Health Study to examine risk of intracranial glioma in the non-metropolitan population. This population-based, case-control study evaluated associations between gliomas and rural and farm exposures among adults (ages 18 to 80) in four upper midwestern states (Iowa, Michigan, Minnesota, Wisconsin). At diagnosis/selection, participants lived in non-metropolitan counties where the largest population center had fewer than 250,000 residents. Cases were diagnosed 1 January 1995 through 31 January 1997. Over 90% of 873 eligible ascertained cases and over 70% of 1670 eligible controls consented to participate. Participants and nonparticipants, evaluated for "critical questions" on main and refusant questionnaires, differed significantly in farming and occupational experience, ethnicity, education, and lifestyle. The 1,175 controls were more likely than the 798 cases to have reported ever drinking alcohol (77% vs. 73%, adjusted odds ratio (OR) 0. 73, 95% confidence interval (CI) 0.59-0.92) and having had panoramic dental x-rays (34% vs. 29%, OR 0. 75, CI 0.61-0.92). Controls spent a greater percentage of their lives in non-metropolitan counties (78% vs. 75%, OR 0.81, CI 0.67-1.09). Among ever-farmers, controls were more likely to have had exposure to farm insecticides (57% vs. 50%, OR 0.75, CI 0.59-0.95) and farm animals (96% vs. 91%, OR 0.48, CI 0.25-0.90). Moving to a farm as an adolescent (ages 11 to 20) vs. as an adult was associated with a greater risk of glioma. In our study sample, farm or rural residence and summary farm exposures were associated with decreased glioma risk. However, nonparticipation by never-farming eligible controls could have affected results. Comparisons of farm chemical exposures may clarify associations between farming and glioma that others have reported.

Adolescent↗
PubMed2004

Knowledge management in occupational hygiene: the United States example.

Knowledge management is an emerging field focusing on assessing the creation, transfer, and utilization of knowledge to address specific challenges. Generally, knowledge management has described efforts within and between companies to consider knowledge as a manageable asset. In this paper, we suggest that occupational hygiene knowledge can be considered a manageable asset by businesses and that the entire field of occupational hygiene in the USA can be appraised in terms of knowledge management. The knowledge cycle creates a foundation for knowledge management. Knowledge creation (research, recognition and evaluation), transfer (distribution, dissemination and diffusion), and utilization (risk management and control) make up the key elements of the knowledge cycle. Defining and understanding the roles of knowledge cycle elements facilitate the application of knowledge management to problems, systems, and situations in individual companies and in the field of occupational hygiene in general. Examples of current, effective knowledge management practices within occupational hygiene in the USA are described, and recommendations for further utilization of knowledge management principles are also presented.

Clinical Competence↗
PubMed2004

Some implications of genetic biomarkers in occupational epidemiology and practice.

This paper addresses the use of genetic biomarkers in occupational epidemiology and some of the scientific, ethical, and social implications for epidemiologists and practitioners to consider, including issues involving individual risk estimation, the communication of epidemiologic results, and the translation of epidemiologic data into clinical or occupational health practice. Three scenarios from the occupational setting illustrate some of these issues and implications. The scenarios involve glutathione-S-transferase theta 1 (GSTT1) and hematopoietic cancer in hospital workers, human leukocyte antigen coding for glutamic acid in the 69th position (HLA DPB1(E69)) and chronic beryllium disease in beryllium workers, and peripheral myelin protein 22 (PMP22) deletion and carpal tunnel syndrome in railroad track workers. Epidemiologic research involving genetic biomarkers requires the application of genetic tests and can be considered on a continuum between basic sciences and clinical and occupational and public health practice for which questions of test relevance, validity, and utility become important.

Environmental Monitoring↗
PubMed2003

Information dissemination and use: critical components in occupational safety and health.

BACKGROUND: Information dissemination is a mandated, but understudied, requirement of occupational and environmental health laws and voluntary initiatives. Research is needed on the factors that enhance and limit the development, transfer, and use of occupational safety and health information (OSH). Contemporary changes in the workforce, workplaces, and the nature of work will require new emphasis on the dissemination of information to foster prevention. METHODS: Legislative and regulatory requirements and voluntary initiatives for dissemination of OSH information were identified and assessed. Literature on information dissemination was reviewed to identify important issues and useful approaches. RESULTS: More than 20 sections of laws and regulations were identified that mandated dissemination of occupational and environmental safety and health information. A four-stage approach for tracking dissemination and considering the flow of information was delineated. Special areas of dissemination were identified: the information needs of the changing workforce, new and young workers; small businesses; and workers with difficulty in understanding or reading English. CONCLUSIONS: We offer a framework for dissemination of OSH information and underscore the need to focus on the extent to which decision-makers and others receive and use such information. More solid data are also needed on current investments in disseminating, diffusing and applying OSH information and on the utility of that information. Am. J. Ind. Med. 44:515-531, 2003. Published 2003 Wiley-Liss, Inc.

Humans↗
PubMed2001

Hemoglobin adducts and sister chromatid exchanges in hospital workers exposed to ethylene oxide: effects of glutathione S-transferase T1 and M1 genotypes.

Ethylene oxide (EtO) is a genotoxic carcinogen with widespread uses as an industrial chemical intermediate and sterilant. We examined the effects of glutathione S-transferase T1 (GSTT1) and M1 (GSTM1) genotypes on the levels of N-(2-hydroxyethyl)valine (HEV) adducts in the erythrocytes and sister chromatid exchange (SCE) in lymphocytes from a group of 58 operators of sterilizers that used EtO and nonexposed workers from nine hospitals in the United States and one hospital in Mexico City. Cumulative exposure to EtO was estimated during the 4-month period before the collection of blood samples. Results showed that EtO exposure was significantly associated with the levels of HEV adducts and SCE after adjusting for cigarette smoking and other potential confounders. A significantly higher HEV adduct level (0.17 +/- 0.03 versus 0.08 +/- 0.01, mean +/- SE; P = 0.02) but lower SCE frequency (5.31 +/- 0.39 versus 6.21 +/- 0.17; P = 0.04) was observed in subjects with homozygous deletion of the GSTT1 gene (null genotype) as compared with those with at least one copy of the gene (positive genotype). In multiple regression analysis, the GSTT1-null genotype was associated with an increase in HEV adduct level (beta = 1.62; P = 0.02) and a decrease in SCE frequency (beta = -1.25; P = 0.003) after adjusting for age, gender, race, education, cigarette smoking, and EtO exposure status. The inverse SCE-GSTT1 relationship remained unchanged when SCE was further examined in relation to HEV adducts as an indicator of the internal EtO dose. The GSTM1 genotype was not associated with the level of either HEV adduct or SCE. These data indicate that the GSTT1-null genotype is associated with increased formation of EtO-hemoglobin adducts in relation to occupational EtO exposure, suggesting that individuals with homozygous deletion of the GSTT1 gene may be more susceptible to the genotoxic effects of ETO: The unexpected finding of decreased SCEs, which is less clear, may be attributed to the nonchemical specificity of this end point and the lack of expression of the GSTT1 enzyme in lymphocytes.

Adult↗
PubMed1999

Ethical issues in the use of genetic markers in occupational epidemiologic research.

This review was conducted to characterize the nature of contemporary occupational epidemiologic research involving genetic markers, consider how genetic information is unique with regard to its social applications, and examine some of the ethical dilemmas that may arise over the course of studies. We have reviewed the literature and the lessons from our experience in conducting occupational epidemiologic research involving genetic markers. This review describes how occupational epidemiologic studies differ from other epidemiologic studies on issues of participation, confidentiality, and the history of including genetic markers. Of primary concern in occupational studies are genes that have multiple alleles and are sometimes referred to as "metabolic polymorphisms." They generally do not confer risk on their own but rather only in combination with a specific exposure. There is a need for a clear policy and guidelines for the conduct of occupational epidemiologic studies using genetic material. This policy should address all of the steps in study design, implementation, interpretation, and communication of results.

Epidemiologic Studies↗
PubMed1999

Using molecular epidemiology in assessing exposure for risk assessment.

Quantitative estimation of health risks depends on exposure characterization, the nature of the dose response relationships, and the toxicity of the agents involved. The greatest uncertainties in risk assessment almost always arise from sparse or inadequate exposure data, inadequate understanding of exposure mechanisms, and insufficient understanding of the exposure-dose-response pathway. Additional sources of uncertainty arise when mixed or multiple exposures are implicated in the disease pathway, and as a result of variability in both exposures and responses within and between individuals. Here we consider the role of exposure assessment in the risk assessment process, the use of biological markers or molecular epidemiology to contribute to improvements in exposure assessment for risk assessment, and uncertainties associated with the use of biological markers.

Biomarkers↗
PubMed1998

Underlying and multiple cause mortality in a cohort of workers exposed to aromatic amines.

BACKGROUND: The National Institute for Occupational Safety and Health (NIOSH) has previously conducted studies of bladder cancer incidence and mortality at a synthetic dye plant that manufactured beta-naphthylamine from 1940 through 1979. This report extends the period of mortality follow-up 13 years and analyzes both underlying and nonunderlying causes of death. METHODS: The vital status of each cohort member, as of December 31, 1992, was determined by using the National Death Index and information from the Internal Revenue Service and the U.S. Postal Service. The NIOSH life table analysis system (LTAS) was used to generate person-year-at-risk and the expected numbers of death for 92 categories of death, using several referent rates (U.S. underlying, Georgia underlying, U.S. multiple cause). RESULTS: There were three bladder cancer deaths listed as underlying cause, yielding a standardized mortality ratio (SMR) based on U.S. rates of 2.4 (95% confidence interval (CI) = 0.5, 7.0) and a total of eight bladder cancers listed anywhere on the death certificates (SMR based on multiple cause referent rates = 5.6; 95% CI = 2.4, 11.1). Mortality from esophageal cancer, which had been significantly elevated in the previous study, was no longer significantly elevated (SMR = 2.0; 95% CI = 0.8, 4.1). Mortality from all causes was significantly higher than expected (SMR = 1.5; 95% CI = 1.3, 1.6). CONCLUSIONS: The elevated bladder cancer risk in this cohort was detected by the multiple cause, but not the underlying cause, analysis. Elevated mortality from other causes of death, especially among short-term workers, may be related to regional and lifestyle factors.

Amines↗
PubMed1997

Transitional studies.

Transitional studies are studies using biological markers that bridge the gap between laboratory experiments and population-based epidemiology. The goal of these studies is to characterize and validate biomarkers and to assess the following: intra- and inter-subject variability; the feasibility of marker use in field conditions; confounding and effect-modifying factors for the marker; and mechanisms reflected by the biomarker. Another goal is to optimize the conditions for the use of biomarkers. Transitional studies involving biomarkers of exposure or effect are distinguished from etiological studies because the biomarker is generally the outcome or dependent variable. Despite this difference, transitional studies can be epidemiological studies, but they may also include laboratory studies to assess reliability (and accuracy) and to identify parameters for collecting, processing and storing biological specimens prior to assay. Generally, transitional studies involve healthy people, patients or workers with specific exposures. At some point in the validation of a biomarker the line between transitional and etiological studies becomes blurred. None the less, it is useful to identify transitional studies as a distinct set of efforts to validate and characterize biomarkers. Transitional studies can be divided into three functional categories: developmental, characterization and applied studies.

Animals↗
PubMed1997

Ethical and social issues in the use of biomarkers in epidemiological research.

The use of biomarkers in epidemiological research may raise ethical and social issues. These issues stem from the belief that research participants have 'rights' to appropriate information before, during and after studies so that they can make informed decisions. Ethical issues can arise during protocol development, obtaining participation, and in the interpretation and notification of text and study results. Additionally, there are ethical considerations concerning the use of biological specimens collected and stored for one purpose and subsequently used for other research purposes. A major ethical issue is the maintenance of participants' privacy and the confidentiality of their test and study results. Ethics committees need to be well-informed about the scope, limitations and expectations of biomarker research in order to be able to respond to social and scientific developments in the use of biomarkers.

Biomarkers↗
PubMed1997

Projection of molecular epidemiology in medicine.

Molecular epidemiology is a term to describe the incorporation of molecular and other types of biomarkers into epidemiology. Molecular epidemiology uses the same paradigm as traditional epidemiology but the former represents the opportunity to use the enhances resolving power of molecular biology and contemporary biochemical science to assess exposure disease relationships. There are three types of biomarkers that can be used in this regard: They include markers of exposure, effect and susceptibility. These markers can be used as dependent and independent variables in most epidemiologic study designs. Critical in their use is that they are validated and field tested. This requires extensive collaboration between laboratory and public health scientist. Special attention also needs or be paid to the interpretation and communication of biomarker data and the ethical issues attendant to their use.

Biomarkers↗
PubMed1996

The impact of interindividual variation in NAT2 activity on benzidine urinary metabolites and urothelial DNA adducts in exposed workers.

Several epidemiologic studies indicate that NAT2-related slow N-acetylation increases bladder cancer risk among workers exposed to aromatic amines, presumably because N-acetylation is important for the detoxification of these compounds. Previously, we showed that NAT2 polymorphisms did not influence bladder cancer risk among Chinese workers exposed exclusively to benzidine (BZ), suggesting that NAT2 N-acetylation is not a critical detoxifying pathway for this aromatic amine. To evaluate the biologic plausibility of this finding, we carried out a cross-sectional study of 33 workers exposed to BZ and 15 unexposed controls in Ahmedabad, India, to evaluate the presence of BZ-related DNA adducts in exfoliated urothelial cells, the excretion pattern of BZ metabolites, and the impact of NAT2 activity on these outcomes. Four DNA adducts were significantly elevated in exposed workers compared to controls; of these, the predominant adduct cochromatographed with a synthetic N-(3'- phosphodeoxyguanosin-8-yl)-N'-acetylbenzidine standard and was the only adduct that was significantly associated with total BZ urinary metabolites (r = 0.68, P < 0.0001). To our knowledge this is the first report to show that BZ forms DNA adducts in exfoliated urothelial cells of exposed humans and that the predominant adduct formed is N-acetylated, supporting the concept that monofunctional acetylation is an activation, rather than a detoxification, step for BZ. However, because almost all BZ-related metabolites measured in the urine of exposed workers were acetylated among slow, as well as rapid, acetylators (mean +/- SD 95 +/- 1.9% vs. 97 +/- 1.6%, respectively) and NAT2 activity did not affect the levels of any DNA adduct measured, it is unlikely that interindividual variation in NAT2 function is relevant for BZ-associated bladder carcinogenesis.

Adult↗
PubMed1996

Intervention research: science, skills, and strategies.

Despite a rich history of etiological research, the field of occupational safety and health does not have a rigorous history of research on what works and does not work to prevent and control occupational diseases and injuries. National and global transformations of economies and workplaces with enhanced competitiveness require more attention to options for interventions. A three-pronged approach to building a body of knowledge on intervention research in occupational health and safety is identified in this paper. The approach focuses on the science, skills, and strategies that can be useful in intervention research. Scientifically, researchers can draw on constructs and techniques from epidemiology, evaluation practice, and clinical trials. Experimental and nonexperimental approaches have value for occupational studies. The skills needed represent a range of disciplines beyond those traditional of health and safety; social scientists, economists, and organizational theorists often need to be part of research teams. Strategic approaches involve more labor-management partnerships, prospective study designs, and the use of intermediate and surrogate indicators. The strategic challenge will be to conduct intervention research against a backdrop of overriding political and economic pressures.

Clinical Trials as Topic↗
PubMed1996

Methodological issues for intervention research in occupational health and safety.

This article presents a brief summary of the nature and extent of intervention research being conducted in the area of occupational safety and health. Articles were classified either as engineering, administrative, or behavioral, according to the type(s) of interventions that were evaluated. Findings suggest that many of the intervention studies conducted lacked a theoretical basis, used small samples, and tested interventions lacking the intensity to cause the desired change. Most study designs were either nonexperimental or quasi-experimental. Recommendations for conducting future research are presented.

Behavior↗