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Biomedical subjects

Paul A Schulte

Publications and source records attributed to Paul A Schulte.

17 recordsLinked to original sources

The genetic and environmental factors involved in benzidine metabolism and bladder carcinogenesis in exposed workers.

Genetic susceptibility to bladder cancer in individuals exposed to arylamines may be explained by interindividual metabolic differences that lead to arylamine bioactivation or detoxification. In this article, occupational bladder cancer risk factors and the evidence that links benzidine exposure to bladder cancer are reviewed. Benzidine metabolism is described and compared with that of other aromatic amines. Metabolic polymorphisms and bladder cancer in the context of occupational exposure to aromatic amines are also reviewed, and the environmental and genetic relationships of benzidine exposure and genetic susceptibility are outlined. Only a few studies of bladder cancer genetic susceptibility in populations exposed occupationally to arylamines have been published. The results of these case-control studies show conflicting results, reflecting metabolic differences between monoarylamines and diarylamines such as benzidine. Additional studies and pooled analyses of existing data are needed to establish if individuals are at higher risk of bladder cancer given the presence of certain alleles that make them more susceptible to this disease.

Acetyltransferases↗

NAT2 slow acetylation and bladder cancer in workers exposed to benzidine.

This study expands a previous study of NAT2 polymorphisms and bladder cancer in male subjects occupationally exposed only to benzidine. The combined analysis of 68 cases and 107 controls from a cohort of production workers in China exposed to benzidine included 30 new cases and 67 controls not previously studied. NAT2 enzymatic activity phenotype was characterized by measuring urinary caffeine metabolite ratios. PCR-based methods identified genotypes for NAT2, NAT1 and GSTM1. NAT2 phenotype and genotype data were consistent. A protective association was observed for the slow NAT2 genotype (bladder cancer OR = 0.3; 95% CI = 0.1 = 1.0) after adjustment for cumulative benzidine exposure and lifetime smoking. Individuals carrying NAT1wt/*10 and NAT1*10/*10 showed higher relative risks of bladder cancer (OR = 2.8, 95% CI = 0.8-10.1 and OR = 2.2, 95% CI = 0.6-8.3, respectively). No association was found between GSTM1 null and bladder cancer. A metaanalysis risk estimate of case-control studies of NAT2 acetylation and bladder cancer in Asian populations without occupational arylamine exposures showed an increased risk for slow acetylators. The lower limit of the confidence interval (OR = 1.4; 95% CI = 1.0-2.0) approximated the upper confidence interval for the estimate obtained in our analysis. These results support the earlier finding of a protective association between slow acetylation and bladder cancer in benzidine-exposed workers, in contrast to its established link as a risk factor for bladder cancer in people exposed to 2-naphthylamine and 4-aminobiphenyl. Study findings suggest the existence of key differences in the metabolism of mono- and diarylamines.

Acetylation↗

The use of biomarkers in surveillance, medical screening, and intervention.

Building on mechanistic information, much of molecular epidemiologic research has focused on validating biomarkers, that is, assessing their ability to accurately indicate exposure, effect, disease, or susceptibility. To be of use in surveillance, medical screening, or interventions, biomarkers must already be validated so that they can be used as outcomes or indicators that can serve a particular function. In surveillance, biomarkers can be used as indicators of hazard, exposure, disease, and population risk. However, to obtain rates for these measures, the population at risk will need to be assessed. In medical screening, biomarkers can serve as early indicators of disease in asymptomatic people. This allows for the identification of those who should receive diagnostic confirmation and early treatment. In intervention (which includes risk assessment and communication, risk management, and various prevention efforts), biomarkers can be used to assess the effectiveness of a prevention or control strategy as well as help determine whether the appropriate individuals are assigned to the correct intervention category. Biomarkers can be used to provide group and individual risk assessments that can be the basis for marshalling resources. Critical for using biomarkers in surveillance, medical screening, and intervention is the justification that the biomarkers can provide information not otherwise accessible by a less expensive and easier-to-obtain source of information, such as medical records, surveys, or vital statistics. The ability to use validated biomarkers in surveillance, medical screening, and intervention will depend on the extent to which a strategy for evidence-based procedures for biomarker knowledge transfer can be developed and implemented. This will require the interaction of researchers and decision-makers to collaborate on public health and medical issues.

Biomarkers↗

Potential occupational risks for neurodegenerative diseases.

BACKGROUND: Associations between occupations and neurodegenerative diseases (NDD) may be discernable in death certificate data. METHODS: Hypotheses generated from 1982 to 1991 study were tested in data from 22 states for the years 1992-1998. Specific occupations and exposures to pesticides, solvents, oxidative stressors, magnetic fields, and welding fumes were evaluated. RESULTS: About one third (26/87) of the occupations hypothesized with neurodegenerative associations had statistically significant elevated mortality odds ratios (MOR) for the same outcome. Occupations with the largest MORs were (a) for presenile dementia (PSD)-dentists, graders/sorters (non-agricultural), and clergy; (b) for Alzheimer's disease (AD)-bank tellers, clergy, aircraft mechanics, and hairdressers; (c) for Parkinson's disease (PD)-biological scientists, clergy, religious workers, and post-secondary teachers; and (d) for motor neuron disease (MND)-veterinarians, hairdressers, and graders and sorters (non-agricultural). Teachers had significantly elevated MORs for all four diseases, and hairdressers for three of the four. Non-horticultural farmers below age 65 had elevated PD (MOR = 2.23, 95% CI = 1.47-3.26), PSD (MOR = 2.22, 95% CI = 1.10-4.05), and AD (MOR = 1.76, 95% CI = 1.04-2.81). Sixty hertz magnetic fields exhibited significant exposure-response for AD and, below age 65, for PD (MOR = 1.87, 95% CI = 1.14-2.98) and MND (MOR = 1.63, 95% CI = 1.10-2.39). Welding had elevated PD mortality below age 65 (MOR = 1.77, 95% CI = 1.08-2.75). CONCLUSIONS: Support was observed for hypothesized excess neurodegenerative disease associated with a variety of occupations, 60 Hz magnetic fields and welding.

Adult↗

Characterizing the burden of occupational injury and disease.

OBJECTIVES: To review the literature on the burden of occupational disease and injury and to provide a comprehensive characterization of the burden. METHODS: The scientific and governmental literature from 1990 to the present was searched and evaluated. Thirty-eight studies illustrative of the burden of occupational disease were reviewed for findings, methodology, strengths, and limitations. RESULTS: Recent U.S. estimates of occupational mortality and morbidity include approximately 55,000 deaths (eighth leading cause) and 3.8 million disabling injuries per year, respectively. Comprehensive estimates of U.S. costs related to these burdens range between dollar 128 billion and dollar 155 billion per year. Despite these significant indicators, occupational morbidity, mortality, and risks are not well characterized in comparative burden assessments. CONCLUSIONS: The magnitude of occupational disease and injury burden is significant but underestimated. There is a need for an integrated approach to address these underestimates.

Cost of Illness↗

Gliomas and farm pesticide exposure in women: the Upper Midwest Health Study.

An excess incidence of brain cancer in male farmers has been noted in several studies, but few studies have focused on women. The National Institute for Occupational Safety and Health Upper Midwest Health Study evaluated effects of rural exposures for 341 female glioma cases and 528 controls, all adult (18-80 years of age) nonmetropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin. On average, controls lived longer on farms than did cases. After adjusting for age, age group, education, and farm residence, no association with glioma was observed for exposure to arsenicals, benzoic acids, carbamates, chloroacetanilides, dinitroanilines, inorganics, organochlorines, organophosphates, phenoxys, triazines, or urea-based or estrogenic pesticides. An increased risk of glioma was observed for carbamate herbicides but was not statistically significant (odds ratio = 3.0; 95% confidence interval, 0.9-9.5). No association was observed between glioma and exposure to 12 widely used specific pesticides, after adjustment for age, age group, education, and any other pesticide exposure. These results were not affected after exclusion of proxy respondents (43% of cases, 2% of controls). Women were less likely than men to have applied pesticides, but more likely to have laundered pesticide-contaminated clothes. Storing pesticides in the house was associated with a statistically non-significant increased risk. Results show that exposure to pesticides was not associated with an increased risk of intracranial gliomas in women. Other farm-related factors could be etiologic factors and will be discussed in future reports.

Adolescent↗

Integrating occupational safety and health information into vocational and technical education and other workforce preparation programs.

The high rates of injury among young workers are a pressing public health issue, especially given the demand of the job market for new workers. Young and new workers experience the highest rates of occupational injuries of any age group. Incorporating occupational safety and health (OSH) information into the more than 20 000 vocational and other workforce preparation programs in the United States might provide a mechanism for reducing work-related injuries and illnesses among young and new workers. We assessed the status of including OSH information or training in workforce preparation programs and found there is an inconsistent emphasis on OSH information.

Accidents, Occupational↗

Gliomas and farm pesticide exposure in men: the upper midwest health study.

The National Institute for Occupational Safety and Health evaluated farm pesticide exposure and glioma risk in a study that included 457 glioma cases and 648 population-based controls, all adult men (18-80 yr old) and nonmetropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin. Multiple logistic regressions were used to control for farm residence, age, age group, education, and exposure to other pesticides. No associations were found between glioma and 12 specific pesticides. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) and found reduced glioma risk for insecticides (OR = 0.53, CI = 0.37-0.77), fumigants (OR = 0.57, CI = 0.34-0.95), and organochlorines (OR = 0.66, CI = 0.47-0.94). In analyses excluding proxy respondents (47% of cases) most CIs included 1.0. No positive association of farm pesticide exposure and glioma was found. Other farm exposures may explain the excess brain cancer risk seen in previous studies.

Adolescent↗

Reproductive factors and risk of glioma in women.

OBJECTIVE: Glioma is the most common primary malignant brain tumor in adults, responsible for 75% of adult primary malignant brain tumors, yet aside from its association with ionizing radiation, its etiology is poorly understood. Sex differences in brain tumor incidence suggest that hormonal factors may play a role in the etiology of these tumors, but few studies have examined this association in detail. The objective of this study was to explore the role of reproductive factors in the etiology of glioma in women. METHOD: As part of a population-based case-control study, histologically confirmed primary glioma cases (n = 341 women) diagnosed between January 1, 1995 and January 31, 1997 were identified through clinics and hospitals in four Midwest U.S. states. Controls (n = 527 women) were randomly selected from lists of licensed drivers and Health Care Finance Administration enrollees. In-person interviews with subjects (81%) or their proxies (19%) collected reproductive history and other exposure information. RESULTS: Glioma risk increased with older age at menarche (P for trend = 0.009) but only among postmenopausal women. Compared with women who never breast-fed, women who breast-fed >18 months over their lifetime were at increased risk of glioma (odds ratio, 1.8; 95% confidence interval, 1.1-2.9). Women who reported using hormones for symptoms of menopause had a decreased risk of glioma compared with women who never used such hormones (odds ratio, 0.7; 95% confidence interval, 0.5-1.1). CONCLUSION: These results support the hypothesis that reproductive hormones play a role in the etiology of glioma among women.

Adult↗

Symptomatic spinal arachnoid cysts: report of two cases with review of the literature.

STUDY DESIGN: Two unusual cases of intradural extramedullary noncommunicating arachnoid cysts are presented, with a review of literature. OBJECTIVE: To assess surgical excision results in the reversal of symptoms and neurologic deficits. SUMMARY OF BACKGROUND DATA: Most patients harboring arachnoid cysts are asymptomatic. Noncommunicating intradural extramedullary arachnoid cysts are more rare than communicating intradural extramedullary cysts. Noncommunicating intradural extramedullary arachnoid cysts are a very rare cause of spinal cord compression. Rarely, these cysts can present with bizarre symptoms, such as angina. MATERIALS AND METHODS: The first case, a 75-year-old woman, presented with progressive paraparesis. The second case, a 40-year-old man, presented with signs and symptoms of angina, with mild spasticity in the lower limbs. In both cases, magnetic resonance imaging revealed compression of the spinal cord as the etiology of presentation. The first patient is the second oldest patient in the literature with an idiopathic spinal arachnoid cyst. The second case has an unusual presentation that has not previously been reported in the literature. RESULTS: Both cases underwent surgical excision of the arachnoid cyst, with resolution of symptoms and reversal of neurologic deficit. CONCLUSIONS: Our experience indicates that complete recovery from an arachnoid cyst is possible after surgical excision, even when symptoms are present for a long duration, even in the elderly.

Adult↗

Assessment of the scientific basis for genetic testing of railroad workers with carpal tunnel syndrome.

In 2000, approximately 20 railroad track workers who filed injury reports or compensation claims for carpal tunnel syndrome were tested by their employer for two genetic traits to determine the work relatedness of the condition. The testing involved deletions, variants, or mutations in the genetic coding for peripheral myelin protein (PMP22) and transthyretin (TTR). This article is an assessment of whether there is a scientific basis for such testing. A review of the scientific literature indicated that neither the scientific basis nor the population validity of the PMP22 or TTR tests for carpal tunnel syndrome were adequately established before use on railroad track workers in 2000. Although ethical and legal issues may predominate in this case, the absence of a compelling scientific basis undermines the decision to conduct the tests.

Carpal Tunnel Syndrome↗

Priorities for development of research methods in occupational cancer.

Occupational cancer research methods was identified in 1996 as 1 of 21 priority research areas in the National Occupational Research Agenda (NORA). To implement NORA, teams of experts from various sectors were formed and given the charge to further define research needs and develop strategies to enhance or augment research in each priority area. This article is a product of that process. Focus on occupational cancer research methods is important both because occupational factors play a significant role in a number of cancers, resulting in significant morbidity and mortality, and also because occupational cohorts (because of higher exposure levels) often provide unique opportunities to evaluate health effects of environmental toxicants and understand the carcinogenic process in humans. Despite an explosion of new methods for cancer research in general, these have not been widely applied to occupational cancer research. In this article we identify needs and gaps in occupational cancer research methods in four broad areas: identification of occupational carcinogens, design of epidemiologic studies, risk assessment, and primary and secondary prevention. Progress in occupational cancer will require interdisciplinary research involving epidemiologists, industrial hygienists, toxicologists, and molecular biologists.

Animals↗

Approaches to sharing occupational safety and health information on a global scale.

BACKGROUND: The global burden of occupational morbidity and mortality is staggering. Information sharing has been identified as a major way of reducing this burden. Past and current approaches to such sharing and application are worth examining in order to guide future efforts. METHODS: Recent literature from international agencies and others was examined to identify examples of information sharing and to determine the status of such sharing and related issues. Literature was included from the areas of surveillance, priority setting, research, dissemination, and risk management. RESULTS: Examples of global information sharing were identified and lessons were drawn from the issues attendant to them. CONCLUSIONS: Results indicate that a broad range of efforts actively promote the global distribution of occupational safety and health information. To advance global approaches to the sharing of occupational and safety and health information, it is critical to improve the opportunity and capacity to access information. Important objectives in achieving this goal are developing coherent and transparent information policies, conducting research on dissemination, adaptation, and utilization of information, and overcoming barriers to information and training.

Global Health↗

Enhancing occupational safety and health through use of the national skill standards.

In a voluntary national effort, U.S. industry, education, labor, and government have initiated the development of standards for job skills and competencies in jobs in 15 economic sectors. The aim of the skill standards is to maintain a globally competitive workforce. Efforts to include occupational safety and health knowledge and skills as core elements in these standards are described. The first skill standards to include occupational safety and health competencies were developed for the manufacturing sector, evaluated by 3,800 workers in 700 companies, and published. National skill standards can stimulate extensive training in occupational safety and health, with resultant application to a larger percentage of workers than ever before.

Accidents, Occupational↗

Emerging issues in occupational safety and health.

In developed countries, changes in the nature of work and the workforce may necessitate recalibrating the vision of occupational safety and health (OSH) researchers, practitioners, and policymakers to increase the focus on the most important issues. New methods of organizing the workplace, extensive labor contracting, expansion of service and knowledge sectors, increase in small business, aging and immigrant workers, and the continued existence of traditional hazards in high-risk sectors such as construction, mining, agriculture, health care, and transportation support the need to address: 1) broader consideration of the role and impact of work, 2) relationship between work and psychological dysfunction, 3) increased surveillance basis for research and intervention, 4) overcoming barriers to the conduct and use of epidemiologic research, 5) information and knowledge transfer and application, 6) economic issues in prevention, and 7) the global interconnectedness of OSH. These issues are offered to spur thinking as new national research agendas for OSH are considered for developed countries.

Developed Countries↗