The association of forced expiratory volume in one second with occupational exposures in a longitudinal study of adults in a rural community in Iowa.

PURPOSE: The Keokuk County Rural Health Study (KCRHS) is a longitudinal population-based study conducted in rural Iowa. A prior analysis of enrollment data identified an association of airflow obstruction with occupational exposures only among cigarette smokers. The current study used spirometry data from all three rounds to investigate whether level of forced expiratory volume in one second (FEV1) and longitudinal change in FEV1 were associated with occupational vapor-gas, dust, and fumes (VGDF) exposures, and whether these associations were modified by smoking. METHODS: This study sample comprised 1071 adult KCRHS participants with longitudinal data. A job-exposure matrix (JEM) was applied to participants' lifetime work histories to assign exposures to occupational VGDF. Mixed regression models of pre-bronchodilator FEV1 (millimeters, ml) were fit to test for associations with occupational exposures while adjusting for potential confounders. RESULTS: Mineral dust had the most consistent association with change in FEV1, including ever/never ( - 6.3 ml/year) and nearly every level of duration, intensity, and cumulative exposure. Because 92% of participants with mineral dust also had organic dust exposure, the results for mineral dust may be due to a combination of the two. An association of FEV1 level with fumes was observed for high intensity ( - 91.4 ml) among all participants, and limited to cigarette smokers with results of - 104.6 ml ever/never exposed, - 170.3 ml high duration, and - 172.4 ml high cumulative. CONCLUSION: The current findings suggest that mineral dust, possibly in combination with organic dust, and fumes exposure, especially among cigarette smokers, were risk factors for adverse FEV1 results.

The association of chronic bronchitis and airflow obstruction with lifetime and current farm activities in a sample of rural adults in Iowa.

OBJECTIVE: Farmers have an increased risk for chronic bronchitis and airflow obstruction. The objective of this study was to investigate the association of these health outcomes with farm activities. METHODS: We evaluated the Keokuk County Rural Health Study (KCRHS) enrollment data for farm activities and the two health outcomes chronic bronchitis based on self-reported symptoms and airflow obstruction based on spirometry. We used logistic regression to model the health outcomes, yielding an odds ratio (OR) and 95% confidence interval (95% CI) for farm activities while adjusting for potential confounders and other risk factors. RESULTS: Of the 1234 farmers, 104 (8.4%) had chronic bronchitis, 75 (6.1%) fulfilled the criteria for airflow obstruction, and the two outcomes overlapped by 18 participants. Chronic bronchitis without airflow obstruction (n = 86) had a statistically significant association with crop storage insecticides (OR 3.1, 95% CI 1.6, 6.1) and a low number of years (≤ 3) worked with turkeys (OR 3.3, 95% CI 1.2, 9.4). The latter result should be interpreted with caution because it is based on a small number of cases (n = 5). Airflow obstruction with or without chronic bronchitis (n = 75) was significantly associated with ever working in a hog or chicken confinement setting (OR 2.2, 95% CI 1.0, 4.5). CONCLUSIONS: These results suggest that work with crop storage insecticides or turkeys may increase the risk for chronic bronchitis and work in hog or chicken confinement may increase the risk for airflow obstruction.

Estimation of the number of workers exposed to respirable crystalline silica by industry: Analysis of OSHA compliance data (1979-2015).

BACKGROUND: Respirable crystalline silica (RCS) can potentially cause silicosis, lung cancer, and renal failure. The current study estimates the percentages of workers potentially overexposed to concentrations of RCS dust and silicosis proportional mortality rates (PMRs) by industry. METHODS: Occupational Safety and Health Administration compliance inspection sampling data for RCS collected during 1979 to 2015 were used to estimate percentages of workers exposed. The results were used in combination with US Census Bureau estimates to produce industry specific worker population estimates for 2014. Estimates of the numbers and percentages of workers exposed to RCS concentrations at least 1, 2, 5, and 10 times the National Institute for Occupational Safety and Health recommended exposure limit (REL) were calculated by industry using the 2002 North American Industry Classification System. Silicosis PMRs by industry were estimated using National Center for Health Statistics multiple cause of death data. RESULTS: RCS concentrations/workers exposed were highest in the poured concrete foundation and structure contractors; commercial and institutional building construction; and masonry contractors. Approximately 100 000 workers were exposed above the RCS REL, and most (79%) worked in the construction industry. Tile and terrazzo contractors (12%); brick, stone, and related construction merchant wholesalers (10%); masonry contractors (6%) and poured concrete foundation and structure contractors (6%) were the highest percentages of workers potentially overexposed. PMRs were highest for the structural clay product manufacturing and the foundries industries. CONCLUSION: Percentages of workers exposed to RCS varied by industry and in some industries workers are exposed over 10 times the REL. Exposures can be reduced below the REL by implementing the hierarchy of controls.

Respirable coal mine dust at surface mines, United States, 1982-2017.

BACKGROUND: Exposure to respirable coal mine dust can cause pneumoconiosis, an irreversible lung disease that can be debilitating. The mass concentration and quartz mass percent of respirable coal mine dust samples (annually, by occupation, by geographic region) from surface coal mines and surface facilities at U.S. underground mines during 1982-2017 were summarized. METHODS: Mine Safety and Health Administration (MSHA) collected and analyzed data for respirable dust and a subset of the samples were analyzed for quartz content. We calculated the respirable dust and quartz concentration geometric mean, arithmetic mean, and percent of samples exceeding the respirable dust permissible exposure limit (PEL) of 2.0 mg/m3, and the average percent of quartz content in samples. RESULTS: The geometric mean for 288 705 respirable dust samples was 0.17 mg/m3 with 1.6% of the samples exceeding the 2.0 mg/m3 PEL. Occupation-specific geometric means for respirable dust in active mining areas were highest among drillers. The geometric mean for respirable dust was higher in central Appalachia compared to the rest of the U.S. The geometric mean for respirable quartz including 54 040 samples was 0.02 mg/m3 with 15.3% of these samples exceeding the applicable standard (PEL or reduced PEL). Occupation-specific geometric means for respirable quartz were highest among drillers. CONCLUSION: Higher concentrations of respirable dust or quartz in specific coal mining occupations, notably drilling occupations, and in certain U.S. regions, underscores the need for continued surveillance to identify workers at higher risk for pneumoconiosis.

Respirable coal mine dust in underground mines, United States, 1982-2017.

BACKGROUND: This study summarized the mass concentration and quartz mass percent of respirable coal mine dust samples (annually, by district, and by occupation) from underground coal mines during 1982-2017. METHODS: Respirable dust and quartz data collected and analyzed by Mine Safety and Health Administration (MSHA) were summarized by year, coal mining occupation, and geographical area. The older (before August 2016) 2.0 mg/m 3 respirable dust MSHA permissible exposure limit (PEL) was used across all years for comparative purposes. For respirable dust and quartz, geometric mean and percent of samples exceeding the respirable dust PEL (2.0 mg/m 3 or a reduced standard for samples with >5% quartz content) were calculated. For quartz samples, the average percent quartz content was also calculated. RESULTS: The overall geometric mean concentration for 681 497 respirable dust samples was 0.55 mg/m 3 and 5.5% of the samples exceeded the 2.0 mg/m 3 PEL. The overall respirable quartz geometric mean concentration for 210 944 samples was 0.038 mg/m 3 and 18.7% of these samples exceeded the applicable standard. There was a decline over time in the percent of respirable dust samples exceeding 2.0 mg/m 3 . The respirable dust geometric mean concentration was lower in central Appalachia compared to the rest of the United States. However, the respirable quartz geometric mean concentration and the mean percent quartz content were higher in central Appalachia. CONCLUSION: This study summarizes respirable dust and quartz concentrations from coal mine inspector samples and may provide an insight into differences in the prevalence of pneumoconiosis by region and occupation.

Occupational Exposures and Subclinical Interstitial Lung Disease. The MESA (Multi-Ethnic Study of Atherosclerosis) Air and Lung Studies.

RATIONALE: The impact of a broad range of occupational exposures on subclinical interstitial lung disease (ILD) has not been studied. OBJECTIVES: To determine whether occupational exposures to vapors, gas, dust, and fumes (VGDF) are associated with high-attenuation areas (HAA) and interstitial lung abnormalities (ILA), which are quantitative and qualitative computed tomography (CT)-based measurements of subclinical ILD, respectively. METHODS: We performed analyses of participants enrolled in MESA (Multi-Ethnic Study of Atherosclerosis), a population-based cohort aged 45-84 years at recruitment. HAA was measured at baseline and on serial cardiac CT scans in 5,702 participants. ILA was ascertained in a subset of 2,312 participants who underwent full-lung CT scanning at 10-year follow-up. Occupational exposures were assessed by self-reported VGDF exposure and by job-exposure matrix (JEM). Linear mixed models and logistic regression were used to determine whether occupational exposures were associated with log-transformed HAA and ILA. Models were adjusted for age, sex, race/ethnicity, education, employment status, tobacco use, and scanner technology. MEASUREMENTS AND MAIN RESULTS: Each JEM score increment in VGDF exposure was associated with 2.64% greater HAA (95% confidence interval [CI], 1.23-4.19%). Self-reported vapors/gas exposure was associated with an increased odds of ILA among those currently employed (1.76-fold; 95% CI, 1.09-2.84) and those less than 65 years old (1.97-fold; 95% CI, 1.16-3.35). There was no consistent evidence that occupational exposures were associated with progression of HAA over the follow-up period. CONCLUSIONS: JEM-assigned and self-reported exposures to VGDF were associated with measurements of subclinical ILD in community-dwelling adults.

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.

A case report of elevated blood cadmium.

A 45-year-old male paint technician was identified as having an elevated whole-blood cadmium of 5.9 microg/l (Occupational and Safety Health Administration reference range for workers:

Occupational Exposure to Vapor-Gas, Dust, and Fumes in a Cohort of Rural Adults in Iowa Compared with a Cohort of Urban Adults.

PROBLEM/CONDITION: Many rural residents work in the field of agriculture; however, employment in nonagricultural jobs also is common. Because previous studies in rural communities often have focused on agricultural workers, much less is known about the occupational exposures in other types of jobs in rural settings. Characterizing airborne occupational exposures that can contribute to respiratory diseases is important so that differences between rural and urban working populations can be assessed. REPORTING PERIOD: 1994-2011. DESCRIPTION OF SYSTEM: This investigation used data from the baseline questionnaire completed by adult rural residents participating in the Keokuk County Rural Health Study (KCRHS). The distribution of jobs and occupational exposures to vapor-gas, dust, and fumes (VGDF) among all participants was analyzed and stratified by farming status (current, former, and never) then compared with a cohort of urban workers from the Multi-Ethnic Study of Atherosclerosis (MESA). Occupational exposure in the last job was assessed with a job-exposure matrix (JEM) developed for chronic obstructive pulmonary disease (COPD). The COPD JEM assesses VGDF exposure at levels of none or low, medium, and high. RESULTS: The 1,699 KCRHS (rural) participants were more likely to have medium or high occupational VGDF exposure (43.2%) at their last job than their urban MESA counterparts (15.0% of 3,667 participants). One fifth (20.8%) of the rural participants currently farmed, 43.1% were former farmers, and approximately one third (36.1%) had never farmed. These three farming groups differed in VGDF exposure at the last job, with the prevalence of medium or high exposure at 80.2% for current farmers, 38.7% for former farmers, and 27.4% for never farmers, and all three percentages were higher than the 15.0% medium or high level of VGDF exposure for urban workers. INTERPRETATION: Rural workers, including those who had never farmed, were more likely to experience occupational VGDF exposure than urban workers. PUBLIC HEALTH ACTION: The occupational exposures of rural adults assessed using the COPD JEM will be used to investigate their potential association with obstructive respiratory health problems (e.g., airflow limitation and chronic bronchitis). This assessment might highlight occupations in need of preventive interventions.

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.

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.