Brent Doney

From Manganism to Manganese-Induced Parkinsonism: A Conceptual Model Based on the Evolution of Exposure

Manganism is a distinct medical condition from Parkinson’s disease. Manganese exposure scenarios in the last century generally have changed from the acute, high-level exposure conditions responsible for the occurrence of manganism to chronic exposure to much lower levels. Such chronic exposures may progressively extend the site of manganese deposition and toxicity from the globus pallidus to the entire area of the basal ganglia, including the substantia nigra pars compacta involved in Parkinson’s disease. The mechanisms of manganese neurotoxicity from chronic exposure to very low levels are not well understood, but promising information is based on the concept of susceptibility that may place individuals exposed to manganese at a higher risk for developing Parkinsonian disturbances. These conditions include mutations of genes which play important pathogenetic roles in both Parkinsonism and in the regulation of manganese transport and metabolism. Liver function is also important in manganese-related neurotoxicity and sub-clinical impairment may increase the risk of Parkinsonism. The purpose and scope of this report are to explore the literature concerning manganese exposure and potential subclinical effects and biological pathways, impairment, and development of diseases such as Parkinsonism and manganism. Inhalation and ingestion of manganese will be the focus of this report.

Industries in the United States with Airborne Beryllium Exposure and Estimates of the Number of Current Workers Potentially Exposed

Estimates of the number of workers in the United States occupationally exposed to beryllium were published in the 1970s and 1980s and ranged from 21,200 to 800,000. We obtained information from several sources to identify specific industries with beryllium exposure and to estimate the number of current workers potentially exposed to beryllium. We spoke with representatives from the primary beryllium industry and government agencies about the number of exposed workers in their facilities. To identify industries in the private sector but outside the primary industry, we used data from the Integrated Management Information System (IMIS), which is managed by the Occupational Safety and Health Administration, and the Health Hazard Evaluation program of the National Institute for Occupational Safety and Health. We used IMIS data from OSHA inspections with a previously developed algorithm to estimate the number of potentially exposed workers in nonprimary industries. Workers potentially exposed to beryllium included 1500 current employees in the primary beryllium industry and 26,500 individuals currently working for the Department of Energy or the Department of Defense. We identified 108 four-digit Standard Industrial Classification (SIC) categories in which at least one measurement of airborne beryllium was ≥ 0.1 μ g/m3. Based on the subset of 94 SIC categories with beryllium ≥ 0.1 μ g/m3, we estimated 26,400 to 106,000 workers may be exposed in the private sector (outside the primary industry). In total, there are as many as 134,000 current workers in government and private industry potentially exposed to beryllium in the United States. We recommend that the results of this study be used to target at-risk audiences for hazard communications intended to prevent beryllium sensitization and chronic beryllium disease.

Estimating the U.S. prevalence of chronic obstructive pulmonary disease using pre- and post-bronchodilator spirometry: the National Health and Nutrition Examination Survey (NHANES) 2007–2010

BackgroundDuring 2007–2010, the National Health and Nutrition Examination Survey (NHANES) conducted a spirometry component which obtained pre-bronchodilator pulmonary lung function data on a nationally representative sample of US adults aged 6–79 years and post-bronchodilator pulmonary lung function data for the subset of adults with airflow limitation. The goals of this study were to 1) compute prevalence estimates of chronic obstructive pulmonary disease (COPD) using pre-bronchodilator and post-bronchodilator spirometry measurements and fixed ratio and lower limit of normal (LLN) diagnostic criteria and 2) examine the potential impact of nonresponse on the estimates.MethodsThis analysis was limited to those aged 40–79 years who were eligible for NHANES pre-bronchodilator spirometry (n=7,104). Examinees with likely airflow limitation were further eligible for post-bronchodilator testing (n=1,110). Persons were classified as having COPD based on FEV1/FVC < 70% (fixed ratio) or FEV1/FVC < lower limit of normal (LLN) based on person’s age, sex, height, and race/ethnicity. Those without spirometry but self-reporting both daytime supplemental oxygen therapy plus emphysema and/or current chronic bronchitis were also classified as having COPD. The final analytic samples for pre-bronchodilator and post-bronchodilator analyses were 77.1% (n=5,477) and 50.8% (n=564) of those eligible, respectively. To account for non-response, NHANES examination weights were adjusted to the eligible pre-bronchodilator and post-bronchodilator subpopulations.ResultsIn 2007–2010, using the fixed ratio criterion and pre-bronchodilator test results, COPD prevalence was 20.9% (SE 1.1) among US adults aged 40–79 years. Applying the same criterion to post-bronchodilator test results, prevalence was 14.0% (SE 1.0). Using the LLN criterion and pre-bronchodilator test results, the COPD prevalence was 15.4% (SE 0.8), while applying the same criterion to post-bronchodilator test results, prevalence was 10.2% (SE 0.8).ConclusionsThe overall COPD prevalence among US adults aged 40–79 years varied from 10.2% to 20.9% based on whether pre- or post-bronchodilator values were used and which diagnostic criterion (fixed ratio or LLN) was applied. The overall prevalence decreased by approximately 33% when airflow limitation was based on post-bronchodilator as compared to pre-bronchodilator spirometry, regardless of which diagnostic criterion was used.

COPD and occupational exposures: a case-control study.

Objective: Evidence demonstrates that occupational exposures are causally linked with chronic obstructive pulmonary disease (COPD). This case-control study evaluated the association between occupational exposures and prevalent COPD based on lifetime occupational history. Methods: Cases (n = 388) aged 45 years and older with COPD were compared with controls (n = 356), frequency matched on age, sex, and cigarette smoking history. Odds ratios for exposure to each of eight occupational hazard categories and three composite measures of exposure were computed using logistic regression. Results: Occupational exposures most strongly associated with COPD were diesel exhaust, irritant gases and vapors, mineral dust, and metal dust. The composite measures describing aggregate exposure to gases, vapors, solvents, or sensitizers (GVSS) and aggregate exposure to dust, GVSS, or diesel exhaust were also associated with COPD. In the small group of never-smokers, a similar pattern was evident. Conclusion: These population-based findings add to the literature linking occupational exposures to COPD.

A Survey of Private Sector Respirator Use in the United States: An Overview of Findings

Limitations of previous surveys of respirator use led the National Institute for Occupational Safety and Health (NIOSH) and the Bureau of Labor Statistics to undertake a survey of respirator use and practices among U.S. private sector employers. The survey was mailed to 40,002 private sector establishments in August 2001; the responses were used to develop national estimates. Respirator use was required in 4.5% of establishments and for 3.1% of employees. Of the establishments requiring respirator use, 95% used air-purifying respirators and 17% used air-supplied respirators. Manufacturing; mining (including oil and gas extraction); construction; and agriculture, forestry, and fishing had the highest rates of establishment respirator use. Respirators were used most frequently to protect against dust/mist, paint vapors, and solvents. Large percentages of establishments requiring respirator use had indicators of potentially inadequate respirator programs. Of establishments requiring respirator use, 91% had at least one indicator of a potentially inadequate respiratory protection program, while 54% had at least five indicators. The survey findings suggest that large numbers of employers may not follow NIOSH recommendations and Occupational Safety and Health Administration (OSHA) and Mine Safety and Health Administration (MSHA) requirements for the selection and use of respirators, potentially putting workers at risk. The findings will aid efforts to increase the appropriate use of respirators in the workplace.

Changes in prevalence of chronic obstructive pulmonary disease and asthma in the US population and associated risk factors

Chronic lower airway diseases, including chronic obstructive pulmonary disease (COPD) and asthma, are currently the third leading cause of death in the United States. We aimed to evaluate changes in prevalence of and risk factors for COPD and asthma among the US adult population. We evaluated changes in prevalence of self-reported doctor-diagnosed COPD (i.e. chronic bronchitis and emphysema) and asthma and self-reported respiratory symptoms comparing data from the 1988–1994 and 2007–2010 National Health and Nutrition Examination Surveys. To investigate changes in the severity of each outcome over the two periods, we calculated changes in the proportions of spirometry-based airflow obstruction for each outcome. Prevalence of doctor-diagnosed chronic bronchitis and emphysema decreased significantly mainly among males, while asthma increased only among females. The self-reported disease and the respiratory symptoms were associated with increased prevalence of airflow obstruction for both periods. However, the prevalence of airflow obstruction decreased significantly in the second period among those with shortness of breath and doctor-diagnosed respiratory conditions (chronic bronchitis, emphysema, and asthma). COPD outcomes and asthma were associated with lower education, smoking, underweight and obesity, and occupational dusts and fumes exposure. Chronic lower airway diseases continue to be major public health problems. However, decreased prevalence of doctor-diagnosed chronic bronchitis and emphysema (in males) and decreased prevalence of airflow obstruction in those with respiratory symptoms and doctor-diagnosed respiratory diseases may indicate a declining trend and decrease in disease severity between the two periods. Continued focus on prevention of these diseases through public health interventions is prudent.

Occupational Risk Factors for COPD Phenotypes in the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study

Abstract Introduction: The contribution of occupational exposure to the risk of chronic obstructive pulmonary disease COPD in population-based studies is of interest. We compared the performance of self-reported exposure to a newly developed JEM in exposure-response evaluation. Methods: We used cross-sectional data from Multi-Ethnic Study of Atherosclerosis (MESA), a population-based sample of 45–84 year olds free of clinical cardiovascular disease at baseline. MESA ascertained the most recent job and employment, and the MESA Lung Study measured spirometry, and occupational exposures for 3686 participants. Associations between health outcomes (spirometry defined airflow limitation and Medical Research Council-defined chronic bronchitis) and occupational exposure [self-reported occupational exposure to vapor-gas, dust, or fumes (VGDF), severity of exposure, and a job-exposure matrix (JEM)-derived score] were evaluated using logistic regression models adjusted for non-occupational risk factors. Results: The prevalence of airflow limitation was associated with self-reported exposure to vapor-gas (OR 2.6, 95%CI 1.1–2.3), severity of VGDF exposure (P-trend < 0.01), and JEM dust exposure (OR 2.4, 95%CI 1.1–5.0), and with organic dust exposure in females; these associations were generally of greater magnitude among never smokers. The prevalence of chronic bronchitis and wheeze was associated with exposure to VGDF. The association between airflow limitation and the combined effect of smoking and VGDF exposure showed an increasing trend. Self-reported vapor-gas, dust, fumes, years and severity of exposure were associated with increased prevalence of chronic bronchitis and wheeze (P < 0.001). Conclusions: Airflow limitation was associated with self-reported VGDF exposure, its severity, and JEM-ascertained dust exposure in smokers and never-smokers in this multiethnic study.

Prevalence of Airflow Obstruction in U.S. Adults Aged 40–79 Years: NHANES Data 1988–1994 and 2007–2010

Abstract Background: The study evaluated the change in the prevalence of airflow obstruction in the U.S. population 40–79 years of age from years 1988–1994 to 2007–2010. Methods: Spirometry data from two representative samples of the U.S. population, the National Health and Nutrition Examination Surveys (NHANES) conducted in 1988–1994 and 2007–2010, were used. The American Thoracic Society/European Respiratory Society (ATS/ERS) criteria were used to define airflow obstruction. Results: Based on ATS/ERS criteria, the overall age-adjusted prevalence of airflow obstruction among adults aged 40–79 years decreased from 16.6% to 14.5% (p < 0.05). Significant decreases were observed for the older age category 60–69 years (20.2% vs. 15.4%; p < 0.01), for males (19.0% vs. 15.4%; p < 0.01), and for Mexican American adults (12.7% vs. 8.4%; p < 0.001). The prevalence of moderate and more severe airflow obstruction decreased also (6.4% vs. 4.4%; p < 0.01). Based on ATS/ERS criteria, during 2007–2010, an estimated 18.3 million U.S. adults 40–79 years had airflow obstruction, 5.6 million had moderate or severe airflow obstruction and 1.4 million had severe airflow obstruction. Conclusions: The overall age-adjusted prevalence of airflow obstruction among U.S. adults aged 40–79 years decreased from 1988–1994 to 2007–2010, especially among older adults, Mexican Americans, and males.

Respirator Use and Practices in Agricultural Crop Production Establishments

ABSTRACT The risk of developing respiratory diseases can be reduced by either wearing respiratory protection under the guidance of an effective respiratory protection program or using controls. In 2001, the Survey of Respirator Use and Practices gathered information on the types of respirators used, respirator use practices, and the respirator program characteristics from 40,002 randomly selected US establishments. This report presents findings of the Survey of Respirator Use and Practices for the Agricultural Production—Crops industry and compares them with National Institute for Occupational Safety and Health (NIOSH) recommendations. Approximately one third of all Agricultural Production—Crops establishments required respirator use. Of the Agricultural Production—Crops establishments that required respirator use, (1) a written program to determine what type of respirator to use was not adopted by management in 73% of the establishments; (2) 21% did not know whether air sampling was conducted for substances for which employees were required to use respirators; (3) 29.5% did not provide respirator training for employees; (4) employees were not assessed for medical fitness to wear a respirator or it was not known whether the employees were assessed, in 49.4%; and (5) the program administrator had received no respirator training in 29.5%. Of the Agricultural Production—Crops establishments that required respirator use, 69.5% had at least 3 indicators of a potentially inadequate respiratory protection program. The high rates of indicators of potential inadequacies suggest widespread problems with respiratory protection programs in the Agricultural Production—Crops industry, indicating a potential for improvement.

Respirator Use Among US Farm Operators: Evidence from the 2006 Farm and Ranch Safety Survey

ABSTRACT The objective of this study was to estimate the national prevalence of respirator use among primary farm operators in the United States. The authors analyzed the 2006 Farm and Ranch Safety Survey data collected for 12,278 actively farming primary farm operators. Weighted prevalence and adjusted prevalence ratios (PRs) of respirator use were calculated by farm operator characteristics, farm characteristics, and selected exposures/hazards. Of the estimated 2.1 million farm operators, 37.2% used a respirator on their farm. Respirator use prevalence was significantly higher among operators aged 16–34 years than those aged ≥65 years (46.9% vs. 30.0%; PR = 1.6); male than female operators (39.0% vs. 24.4%; PR = 1.6); operators managing crop farms than operators managing livestock farms (40.9% vs. 33.7%; PR = 1.2); and operators managing farms with value of sales ≥