Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-19 (of 19 Records) |
Query Trace: Antao V[original query] |
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Response to 'Follow-Up of the Libby, Montana Screening Cohort: A 17-year Mortality Study: Likely Underestimation of Nonmalignant Asbestos-Related Disease'
Larson TC , Williamson L , Antao VC . J Occup Environ Med 2020 62 (5) e235 We thank Drs Miller, Loewen, Szeinuk, and Noonan for their comments and insights regarding the burden of asbestos-related disease (ARD) among current and former Libby residents, as well as on our publication.1 We agree with Dr Loewen’s observation that local physicians may not have noted ARD in this cohort of screening participants. This could have resulted in under-ascertainment of nonmalignant, ARD mortality. (Note that we reported results for asbestosis, a nonmalignant disease defined as interstitial pneumonitis and fibrosis caused by inhalation of asbestos.2) Still, the asbestosis SMRs we reported ranged from 82 (among workers categorized as “other asbestos occupation”) to 558 (among household contacts) in comparison with a national reference population. These SMRs clearly indicate a striking excess of nonmalignant ARD in the screening cohort. |
Follow-up of the Libby, Montana screening cohort: A 17-year mortality study
Larson TC , Williamson L , Antao VC . J Occup Environ Med 2019 62 (1) e1-e6 OBJECTIVE: To evaluate mortality patterns among participants in a community-based screening program for asbestos-related disease. METHODS: We calculated standardized mortality ratios (SMRs) and stratified results by exposure group (three occupational exposure groups, household contacts and residents without occupational asbestos exposure) and by radiographic abnormality presence. RESULTS: All-cause mortality (15.8%; 1,429/8,043) was statistically lower than expected. Asbestosis was statistically elevated in all exposure groups. Lung cancer was moderately associated with vermiculite miner/miller employment. Mesothelioma was elevated in that same exposure group and among residents. Systemic autoimmune disease mortality was also elevated. Radiographic parenchymal abnormalities were associated with lung cancer mortality. CONCLUSION: In addition to asbestos-related mortality in occupational exposure groups, this initial mortality follow-up of this cohort also shows elevated mortality for some asbestos-related causes in non-occupational exposure groups. |
9/11 residential exposures: the impact of World Trade Center dust on respiratory outcomes of lower Manhattan residents
Antao VC , Pallos LL , Graham SL , Shim YK , Sapp JH , Lewis B , Bullard S , Alper HE , Cone JE , Farfel MR , Brackbill RM . Int J Environ Res Public Health 2019 16 (5) Thousands of lower Manhattan residents sustained damage to their homes following the collapse of the Twin Towers on 11 September 2001. Respiratory outcomes have been reported in this population. We sought to describe patterns of home damage and cleaning practices in lower Manhattan and their impacts on respiratory outcomes among World Trade Center Health Registry (WTCHR) respondents. Data were derived from WTCHR Wave 1 (W1) (9/2003(-)11/2004) and Wave 2 (W2) (11/2006(-)12/2007) surveys. Outcomes of interest were respiratory symptoms (shortness of breath (SoB), wheezing, persistent chronic cough, upper respiratory symptoms (URS)) first occurring or worsening after 9/11 W1 and still present at W2 and respiratory diseases (asthma and chronic obstructive pulmonary disease (COPD)) first diagnosed after 9/11 W1 and present at W2. We performed descriptive statistics, multivariate logistic regression and geospatial analyses, controlling for demographics and other exposure variables. A total of 6447 residents were included. Mean age on 9/11 was 45.1 years (+/-15.1 years), 42% were male, 45% had ever smoked cigarettes, and 44% reported some or intense dust cloud exposure on 9/11. The presence of debris was associated with chronic cough (adjusted OR (aOR) = 1.56, CI: 1.12(-)2.17), and upper respiratory symptoms (aOR = 1.56, CI: 1.24(-)1.95). A heavy coating of dust was associated with increased shortness of breath (aOR = 1.65, CI: 1.24(-)2.18), wheezing (aOR = 1.43, CI: 1.03(-)1.97), and chronic cough (aOR = 1.59, CI: 1.09(-)2.28). Dusting or sweeping without water was the cleaning behavior associated with the largest number of respiratory outcomes, such as shortness of breath, wheezing, and URS. Lower Manhattan residents who suffered home damage following the 9/11 attacks were more likely to report respiratory symptoms and diseases compared to those who did not report home damage. |
Response to: 'Pleural abnormalities in the Framingham Heart Study: prevalence and CT image features' by Araki et al
Franzblau A , Antao VC , Pinheiro G , Larson T . Occup Environ Med 2018 75 (1) 77 The report by Araki et al is important for a number of reasons, most significantly that it is the first-ever study of pleural abnormalities potentially related to asbestos in a large, general population (the Framingham Heart Study (FHS) Third Generation cohort) that is based on chest CT scans rather than chest radiographs.1 Pleural abnormalities were reported to be present in 1.5% of the study population. A key conclusion of the study was that the prevalence of pleural abnormalities in the present study was significantly lower than what was observed in NHANES II (3.9%), and this was taken as evidence in support of reduced asbestos exposures in the decades since the National Health and Nutrition Examination Survey (NHANES) II data were collected in the period 1976–1980.2 It is important to note that the results of NHANES II were based on chest radiographs, while the results for the FHS cohort were based on chest CT scans. Because of this difference in radiographic methods, we take issue with the comparison of the results from Araki et al with results from NHANES II.1,2 | | Araki et al noted that since ‘CT scan has a better capacity to detect and characterize pleural plaques and thickening than chest radiography, the decrease in prevalence over several decades could be more substantial’.1 The first part of this sentence acknowledges the fact that chest radiography has a lower sensitivity for the detection of pleural plaques compared with chest CT scan (ie, chest radiography has a considerable rate of false-negative results compared with chest CT scan). However, the article fails to note that chest radiography also has a significant rate of false-positive findings relative to chest CT scan and that the latter is significantly related to body mass index (BMI), age and possibly other factors.3 In the absence of a statistical analysis that adjusts for age, BMI and other factors in the NHANES II and FHS cohorts, it is impossible to know the overall impact of false-positive and false-negative results in NHANES II relative to the FHS. While we concur with the conclusions that asbestos use in the USA has declined since NHANES II and that asbestos exposures in the US population have also likely declined, a simple comparison of chest radiograph and chest CT scan results for pleural plaques is not valid. |
Preliminary Results of National Amyotrophic Lateral Sclerosis (ALS) Registry Risk Factor Survey Data.
Bryan L , Kaye W , Antao V , Mehta P , Muravov O , Horton DK . PLoS One 2016 11 (4) e0153683 BACKGROUND: The National ALS Registry is made up of two components to capture amyotrophic lateral sclerosis (ALS) cases: national administrative databases (Medicare, Medicaid, Veterans Health Administration and Veterans Benefits Administration) and self-identified cases captured by the Registry's web portal. This study describes self-reported characteristics of U.S. adults with ALS using the data collected by the National ALS Registry web portal risk factor surveys only from October 19, 2010 through December 31, 2013. OBJECTIVE: To describe findings from the National ALS Registry's web portal risk factor surveys. MEASUREMENTS: The prevalence of select risk factors among adults with ALS was determined by calculating the frequencies of select risk factors-smoking and alcohol (non, current and former) histories, military service and occupational history, and family history of neurodegenerative diseases such as ALS, Alzheimer's and/or Parkinson's. RESULTS: Nearly half of survey respondents were ever smokers compared with nearly 41% of adults nationally. Most respondents were ever drinkers which is comparable to national estimates. The majority were light drinkers. Nearly one-quarter of survey respondents were veterans compared with roughly 9% of US adults nationally. Most respondents were retired or disabled. The industries in which respondents were employed for the longest time were Professional and Scientific and Technical Services. When family history of neurodegenerative diseases in first degree relatives was evaluated against our comparison group, the rates of ALS were similar, but were higher for Parkinson's disease, Alzheimer's disease and any neurodegenerative diseases. CONCLUSIONS: The National ALS Registry web portal, to our knowledge, is the largest, most geographically diverse collection of risk factor data about adults living with ALS. Various characteristics were consistent with other published studies on ALS risk factors and will allow researchers to generate hypotheses for future research. |
Considerations before establishing an environmental health registry
Antao VC , Muravov OI , Sapp J 2nd , Larson TC , Pallos LL , Sanchez ME , Williamson GD , Horton DK . Am J Public Health 2015 105 (8) e1-e8 Public health registries can provide valuable information when health consequences of environmental exposures are uncertain or will likely take long to develop. They can also aid research on diseases that may have environmental causes that are not completely well defined. We discuss factors to consider when deciding whether to create an environmental health registry. Those factors include public health significance, purpose and outcomes, duration and scope of data collection and availability of alternative data sources, timeliness, availability of funding and administrative capabilities, and whether the establishment of a registry can adequately address specific health concerns. We also discuss difficulties, limitations, and benefits of exposure and disease registries, based on the experience of the Agency for Toxic Substances and Disease Registry. |
Surveillance for occupational respiratory diseases in developing countries
Antao VC , Pinheiro GA . Semin Respir Crit Care Med 2015 36 (3) 449-54 The burden of chronic diseases, including occupational respiratory diseases (ORDs), is increasing worldwide. Nevertheless, epidemiological data on these conditions are scarce in most countries. Therefore, it is important to conduct surveillance to monitor ORDs, particularly in developing countries, where the working population is especially vulnerable and the health system infrastructure is usually weak. This article provides a general framework for the implementation of ORD surveillance in developing countries. The main objectives of surveillance are to describe incidence and prevalence of ORDs, as well as to identify sentinel events and new associations between occupational exposures and health outcomes. Diseases with high morbidity and mortality and those in which early diagnosis with standardized tests are available are especially suitable for surveillance activities. Simple strategies, preferably using existing resources and technology, are the best option for surveillance in developing countries. This article offers examples of specific surveillance systems that are in place in Brazil, China, Cuba, India, and South Africa. |
Prevalence of amyotrophic lateral sclerosis - United States, 2010-2011
Mehta P , Antao V , Kaye W , Sanchez M , Williamson D , Bryan L , Muravov O , Horton K . MMWR Suppl 2014 63 Suppl 7 (7) 1-14 PROBLEM/CONDITION: Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig's disease, is a progressive and fatal neuromuscular disease for which no cure has been identified. Although ALS has no known definitive cause, familial ALS (a hereditary form) occurs in 5%-10% of cases. Many hypotheses have been formulated about what causes ALS, including chemical exposures, occupational exposure, military service, infectious agents, nutritional intake, physical activity, and trauma. Worldwide, ALS affects white males aged >60 years more often than any other group. In the United States, ALS surveillance is necessary to estimate the incidence and prevalence of ALS and collect data on risk factors. ALS is not a nationally notifiable condition in the United States (i.e., it is not a reportable condition in all jurisdictions), and individual state reporting requirements differ, with Massachusetts being the only state that mandates reporting. PERIOD COVERED: October 19, 2010-December 31, 2011. DESCRIPTION OF SYSTEM: In 2009, the federal Agency for Toxic Substances and Disease Registry (ATSDR) implemented the National ALS Registry to collect and analyze data regarding persons with ALS in the United States. The main goals of the Registry, as defined by the 2008 ALS Registry Act, are to describe the incidence and prevalence of ALS better, examine risk factors such as environmental and occupational exposures, and characterize the demographics of those living with ALS. The Registry uses a two-pronged approach to identify all cases of ALS. The first approach uses four existing national administrative databases (maintained by Medicare, Medicaid, the Veterans Health Administration, and the Veterans Benefits Administration) to identify prevalence of ALS. The second approach uses a secure web portal (http://www.cdc.gov/als) that was launched to the public on October 19, 2010, to identify cases not included in the four national administrative databases and to collect risk-factor data on known ALS cases. ALS patients who have registered via the web portal can complete brief risk-factor surveys online that are intended to attain a better understanding of ALS (e.g., genetics and environmental and occupational exposures) and help determine disease progression. RESULTS: During October 19, 2010-December 31, 2011, a total of 12,187 persons meeting the surveillance case definition of definite ALS were identified by the Registry, for a prevalence of 3.9 cases of ALS per 100,000 persons in the U.S. general population. Incidence cannot be measured because the date of diagnosis was not noted in all patient records. Overall, ALS was more common among white males, non-Hispanics, and persons aged 60-69 years. The age groups with the lowest number of persons with ALS were age 18-39 years and age >80 years. Males had a higher prevalence rate of ALS than females overall and across all data sources. INTERPRETATION: This is the first (and to date the only) effort to estimate the national prevalence of ALS in the United States. Using the combined approach of the national databases and the web-based portal enables researchers to estimate ALS prevalence more accurately. Registry findings for the prevalence of ALS are consistent with findings from long-established ALS registries in Europe and from smaller-scale epidemiologic studies conducted previously in the United States. Although incidence cannot be measured with Registry data at this time, incidence is being measured in smaller geographic areas that have participated in ATSDR's State and Metropolitan Area ALS surveillance projects. PUBLIC HEALTH ACTIONS: Data collected by the National ALS Registry are being used to better describe the prevalence of ALS in the United States and to help facilitate research. The combined approach of using national administrative databases and a self-enrollment web portal to collect data is novel and potentially could be used for other non-notifiable diseases such as Parkinson's disease or multiple sclerosis. ATSDR is working closely with ALS advocacy and support groups, researchers, health-care professionals, and others to promote the National ALS Registry in order to capture all cases of ALS. To further enhance and strengthen the Registry, ATSDR is 1) adding new modules to the portal to examine other potential risk factors, 2) launching a feasibility study for a novel ALS biorepository (available at http://wwwn.cdc.gov/als/ALSBioRegistry.aspx) linked to the Registry that would potentially provide biologic specimens from patient enrollees to help researchers learn more about disease etiology, 3) engaging in surveillance activities in selected states and large metropolitan areas to help test the completeness of the Registry as well as calculating incidence in these areas, and 4) using the Registry to recruit patient enrollees for new clinical trials and epidemiologic studies. Additional information about the National ALS Registry is available at http://www.cdc.gov/als or by calling toll-free at 1-877-442-9719. |
Quantifying a nonnotifiable disease in the United States: the National Amyotrophic Lateral Sclerosis Registry model
Horton DK , Mehta P , Antao VC . JAMA 2014 312 (11) 1097-8 Public health surveillance is an essential tool for assessing, controlling, and preventing disease. In the United States, public health surveillance has evolved from a focus on monitoring infectious diseases to also tracking injuries, chronic diseases, birth defects, environmental and occupational exposures, and risk factors.1 Despite this evolution of surveillance topics, many conditions still are not notifiable to federal public health officials nor are there surveillance systems in place to capture such conditions. The lack of morbidity data for nonnotifiable conditions makes it difficult to access accurately the populations at greatest risk and the true economic and societal burden of such diseases. New approaches are needed to more accurately quantify nonnotifiable conditions of interest in the United States, such as amyotrophic lateral sclerosis (ALS). | ALS, also known as Lou Gehrig disease, is a rare disease that affects the upper and lower motor neurons and usually leads to death within 2 to 5 years after diagnosis.2 In 2008, the US Congress passed the ALS Registry Act,3 intended to create a national ALS registry to better describe the incidence and prevalence of ALS, define demographic characteristics of those with ALS, and examine risk factors that may be related to the development of ALS, such as environmental and occupational exposures. Even though the act did not make ALS a notifiable disease, it did allow for the creation of a national population-based registry to collect and analyze data regarding persons living with ALS in the United States. In 2009, the federal Agency for Toxic Substances and Disease Registry (ATSDR), a sister agency of the Centers for Disease Control and Prevention (CDC), launched the National ALS Registry. This registry undertook a novel approach to quantify the burden of ALS using data from national administrative sources and a self-enrollment web portal. Data from both sources are merged and de-duplicated to ensure an accurate case count. |
Impact of body mass index on the detection of radiographic localized pleural thickening
Larson TC , Franzblau A , Lewin M , Goodman AB , Antao VC . Acad Radiol 2014 21 (1) 3-10 RATIONALE AND OBJECTIVES: Subpleural fat can be difficult to distinguish from localized pleural thickening (LPT), a marker of asbestos exposure, on chest radiographs. The aims of this study were to examine the influence of body mass index (BMI) on the performance of radiograph readers when classifying LPT and to model the risk of false test results with varying BMI. MATERIALS AND METHODS: Subjects (n = 200) were patients being screened or treated for asbestos-related health outcomes. A film chest radiograph, a digital chest radiograph, and a high-resolution computed tomography (HRCT) chest scan were collected from each subject. All radiographs were independently read by seven B readers and scored using the International Labour Office system. HRCT scans, read by three experienced thoracic radiologists, served as the gold standard for the presence of LPT. We calculated measures of radiograph reader performance, including sensitivity and specificity, for each image modality. We also used logistic regression to estimate the probability of a false-positive and a false-negative result while controlling for covariates. RESULTS: The proportion of false-positive readings correlated with BMI. While controlling for covariates, regression modeling showed the probability of a false-positive result increased with increasing BMI category, younger age, not having pleural calcification, and among subjects not reporting occupational or household contact asbestos exposure. CONCLUSIONS: Clinicians should be cautious when evaluating radiographs of younger obese persons for the presence of asbestos-related pleural plaque, particularly in populations having an anticipated low or background prevalence of LPT. |
The World Trade Center disaster: a tragic source of medical advancement
Antao VC . Eur Respir J 2013 41 (5) 999-1001 The history of medicine is full of examples of the determination of scientists when faced with public health disasters. As a result of this strength, many tragedies that occurred in the 20th century were followed by important scientific developments. If World War I marked the advent of chemical weapons, it also provided respiratory specialists with knowledge about the effects of poisonous gases on the lungs and led to the development of the first practical gas mask for mass production. The increased use of aircraft in warfare during World War II prompted Forrest M. Bird to develop oxygen masks to enable pilots to fly at higher altitudes than ever before. Further improvements of this technology led to the invention of the first modern ventilators, such as the Bird Universal Medical Respirator. The legacy of the Vietnam War to the medical field was the identification of acute respiratory distress syndrome (called Da Nang Lung at that time), by Colorado researchers in 1967 [1]. Other tragedies, such as the 1986 catastrophic nuclear accident of Chernobyl, led to a better understanding of the physiology of radiation poisoning, which had been evolving since the Hiroshima bombing, and helped improve treatment for victims of other disasters. There were advances in the creation of sterile hospital rooms, infection prevention, intravenous transfusion, life support systems, plasmapheresis, platelet transfusion, and bone marrow transplants. | The dawn of the 21st century saw another tragedy that will remain in the memory of many generations to come: the terrorist attacks on September 11, 2001 in New York City, NY, USA that led to the destruction of the World Trade Center (WTC) Twin Towers and other buildings, and claimed thousands of lives. In the past 10 years, hundreds of manuscripts have been published on the effects of the 9/11 disaster. These papers reported on the findings of several medical monitoring programmes [2–4] as well as the largest post-disaster public health registry in US history [5]; they described new syndromes [6] and striking cases of lung injury [7]; demonstrated the association between lung and mental health problems among rescue/recovery workers [8]; and expanded the understanding of the importance of respiratory protection in disaster situations [9]. In this issue of the European Respiratory Journal, a manuscript by Weiden et al. [10] goes beyond traditional WTC research. It looks at the association between serum levels of cardiovascular biomarkers and subsequent development of pulmonary disease, providing new insights into the pathophysiological mechanisms of particle-induced lung injury in humans. |
Mesothelioma incidence in 50 states and the District of Columbia, United States, 2003-2008
Henley SJ , Larson TC , Wu M , Antao VC , Lewis M , Pinheiro GA , Eheman C . Int J Occup Environ Health 2013 19 (1) 1-10 BACKGROUND: The decline in asbestos use in the United States may impact mesothelioma incidence. OBJECTIVE: This report provides national and state-specific estimates of mesothelioma incidence in the United States using cancer surveillance data for the entire US population. METHODS: Data from the National Program for Cancer Registries and the Surveillance, Epidemiology, and End Results program were used to calculate incidence rates and annual percent change. RESULTS: During 2003-2008, an average of 1.05 mesothelioma cases per 100,000 persons were diagnosed annually in the United States; the number of cases diagnosed each year remained level, whereas rates decreased among men and were stable among women. CONCLUSION: US population-based cancer registry data can be used to determine the burden of mesothelioma and track its decline. Even 30 years after peak asbestos use in the United States, 3200 mesothelioma cases are diagnosed annually, showing that the US population is still at risk. |
The National Amyotrophic Lateral Sclerosis (ALS) registry
Antao VC , Horton DK . J Environ Health 2012 75 (1) 28-30 A myotrophic lateral sclerosis (ALS) is a progressive and often fatal neuromuscular disease. Most people die within 2–5 years of being diagnosed with ALS (Mitsumoto, Chad, & Pioro, 1998). Community concerns about perceived clusters of cases of ALS have challenged public health agencies to consider the possible contribution of environmental contaminants to the development of this disease. The general categories of possible environmental risk factors that have been investigated include heavy metals, trace elements, solvents and other volatile organic chemicals, ionizing and non-ionizing radiation, and agricultural chemicals. | Several investigations have been conducted of heavy metal exposure, particularly lead, as a risk factor for ALS. Some case-control studies demonstrated a positive association between past exposure to lead and risk of ALS (Armon, Kurland, Daube, & O’Brien, 1991; Kamel et al., 2002; Roelofs-Iverson, Mulder, Elveback, Kurland, & Molgaard, 1984). Also, the epidemiologic literature offers some support for an association between ALS and past exposure to organic solvents (Gunnarsson, Lindberg, Söderfeldt, & Axelson, 1991; McGuire et al., 1997). | In addition, certain occupations, such as military work, have been listed as a risk factor for ALS (Nicholas et al., 1998; Schulte, Burnett, Boeniger, & Johnson, 1996; Sutedja et al., 2009; Weisskopf et al., 2005). Several other potential risk factors have been evaluated in the scientific literature including infectious agents (Fang et al., 2011), nutritional intake (Okamoto, Kihira, Kobashi et al., 2009; Wang et al., 2011; Woolsey, 2008), physical activity, and trauma (Beghi et al., 2010; Okamoto, Kihira, Kondo et al., 2009; Piazza, Siren, & Ehrenreich, 2004; Strickland, Smith, Dolliff, Goldman, & Roelofs, 1996). | The uncertainty about the incidence and prevalence of ALS, as well as the lack of knowledge about the role of environmental exposures in the etiology of ALS, has created a need for structured data collection. In 2008, President Bush signed the ALS Registry Act into law, allowing the Agency for Toxic Substances and Disease Registry (ATSDR) to create the National ALS Registry. The purpose of the registry is to quantify the incidence and prevalence of ALS in the U.S., describe the demographics of persons with ALS, and examine risk factors for the disease. |
Associations between radiographic findings and spirometry in a community exposed to Libby amphibole
Larson TC , Lewin M , Gottschall EB , Antao VC , Kapil V , Rose CS . Occup Environ Med 2012 69 (5) 361-6 BACKGROUND: Among asbestos-exposed individuals, abnormal spirometry is usually associated with parenchymal abnormalities or diffuse pleural thickening. Localised pleural thickening (LPT), the most common abnormality associated with asbestos exposure, is typically thought to be a marker of exposure with little clinical consequence. Our objective was to determine if abnormal spirometry is associated with LPT independent of other abnormalities, using data from community-based screening conducted in Libby, Montana. METHODS: Subjects were a subset of screening participants comprising persons with interpretable spirometry and chest radiograph results (n=6475). Chest radiographs were independently evaluated by two or three B readers, and participants were classified by mutually exclusive categories of spirometry outcome: normal, restriction, obstruction or mixed defect. RESULTS: Restrictive spirometry was strongly associated with parenchymal abnormalities (OR 2.9; 95% CI 1.4 to 6.0) and diffuse pleural thickening (OR 4.1; 95% CI 2.1 to 7.8). Controlling for the presence of these abnormalities as well as age, smoking status and other covariates, restrictive spirometry was also associated with LPT (OR 1.4; 95% CI 1.1 to 1.8). The risk of restrictive spirometric findings correlated with the severity of LPT. CONCLUSIONS: In this large community-based screening cohort, restrictive spirometry is significantly associated with LPT, indicating that this abnormality may result in lung function impairment. Physicians treating patients exposed to Libby amphibole should be aware that LPT may have functional consequences. |
Association between cumulative fiber exposure and respiratory outcomes among Libby vermiculite workers
Larson TC , Antao VC , Bove FJ , Cusack C . J Occup Environ Med 2012 54 (1) 56-63 OBJECTIVE: To examine the association between cumulative fiber exposure and health outcomes in workers (n = 336) with Libby amphibole exposure. METHODS: Exposure-response relationships were explored by the use of logistic regression, with cumulative fiber exposure modeled in categories and as a continuous variable. RESULTS: The use of spline functions with lifetime cumulative fiber exposure as a continuous variable showed that the odds of localized pleural thickening were significantly elevated at less than 1 f/cc-y. Odds of parenchymal abnormalities, restrictive spirometry, and chronic bronchitis were also significantly elevated at 108, 166, and 24 f/cc-y, respectively. CONCLUSIONS: The odds of several pulmonary health outcomes are correlated with cumulative exposure to Libby amphibole. That relatively low-lifetime cumulative exposures are associated with localized pleural thickening has implications for the non-cancer-risk assessment for Libby amphibole. |
Libby vermiculite exposure and risk of developing asbestos-related lung and pleural diseases
Antao VC , Larson TC , Horton DK . Curr Opin Pulm Med 2011 18 (2) 161-7 PURPOSE OF REVIEW: The vermiculite ore formerly mined in Libby, Montana, contains asbestiform amphibole fibers of winchite, richterite, and tremolite asbestos. Because of the public health impact of widespread occupational and nonoccupational exposure to amphiboles in Libby vermiculite, numerous related studies have been published in recent years. Here we review current research related to this issue. RECENT FINDINGS: Excess morbidity and mortality classically associated with asbestos exposure have been well documented among persons exposed to Libby vermiculite. Excess morbidity and mortality have likewise been documented among persons with only nonoccupational exposure. A strong exposure-response relationship exists for many malignant and nonmalignant outcomes and the most common outcome, pleural plaques, may occur at low lifetime cumulative exposures. SUMMARY: The public health situation related to Libby, Montana, has led to huge investments in public health actions and research. The resulting studies have added much to the body of knowledge concerning health effects of exposures to Libby amphibole fibers specifically and asbestos exposure in general. |
Comparison of digital with film radiographs for the classification of pneumoconiotic pleural abnormalities
Larson TC , Holiday DB , Antao VC , Thomas J , Pinheiro G , Kapil V , Franzblau A . Acad Radiol 2011 19 (2) 131-40 RATIONALE AND OBJECTIVES: Analog film radiographs are typically used to classify pneumoconiosis to allow comparison with standard film radiographs. The aim of this study was to determine if digital radiography is comparable to film for the purpose of classifying pneumoconiotic pleural abnormalities. MATERIALS AND METHODS: Subjects were 200 asbestos-exposed patients, from whom digital and film chest radiographs were obtained along with chest high-resolution computed tomographic scans. Using a crossover design, radiographs were independently read on two occasions by seven readers, using conventional International Labour Organization standards for film and digitized standards for digital. High-resolution computed tomographic scans were read independently by three readers. Areas under the receiver-operating characteristic curves were calculated using high-resolution computed tomographic ratings as the gold standard for disease status. Mixed linear models were fit to estimate the effects of order of presentation, occasion, and modality, treating the seven readers as a random effect. Comparing digital and film radiography for each reader and occasion, crude agreement and agreement beyond chance (kappa) were also calculated. RESULTS: The linear models showed no statistically significant sequence effect for order of presentation (P = .73) or occasion (P = .28). Most important, the difference between modalities was not statistically significant (digital vs film, P = .54). The mean area under the curve for film was 0.736 and increased slightly to 0.741 for digital. Mean crude agreement for the presence of pleural abnormalities consistent with pneumoconiosis across all readers and occasions was 78.3%, while the mean kappa value was 0.49. CONCLUSIONS: These results indicate that digital radiography is not statistically different from analog film for the purpose of classifying pneumoconiotic pleural abnormalities, when appropriate standards are used. |
Respiratory protective equipment, mask use, and respiratory outcomes among World Trade Center rescue and recovery workers
Antao VC , Pallos LL , Shim YK , Sapp JH 2nd , Brackbill RM , Cone JE , Stellman SD , Farfel MR . Am J Ind Med 2011 54 (12) 897-905 BACKGROUND: Serious respiratory illnesses have been reported among rescue/recovery workers (RRW) following the World Trade Center (WTC) attacks. METHODS: We studied RRW enrolled in the WTC Health Registry to assess the effects of different respiratory protection equipment (RPE) types on respiratory outcomes, such as recurrent respiratory symptoms and diseases possibly associated with 9/11 exposures. We performed descriptive and multivariate analyses adjusting for demographics and exposure variables. RESULTS: A total of 9,296 RRW met inclusion criteria. The strongest predictors of using adequate RPE were being affiliated with construction, utilities or environmental remediation organizations and having received RPE training. Workers who used respirators were less likely to report adverse respiratory outcomes compared to those who reported no/lower levels of respiratory protection. CONCLUSIONS: Level of respiratory protection was associated with the odds of reporting respiratory symptoms and diseases. Training, selection, fit testing, and consistent use of RPE should be emphasized among emergency responders. Am. J. Ind. Med. (c) 2011 Wiley-Liss, Inc. |
Vermiculite worker mortality: estimated effects of occupational exposure to Libby amphibole
Larson TC , Antao VC , Bove FJ . J Occup Environ Med 2010 52 (5) 555-60 OBJECTIVE: To examine the relationship between cumulative fiber exposure (CFE) and mortality in a retrospective cohort study of vermiculite workers exposed to Libby amphibole (n = 1862). METHODS: Extended Cox regression was used to estimate the hazards associated with CFE as a time-dependent covariate of multiple-cause mortality. RESULTS: The Cox models for mesothelioma, asbestosis, lung cancer, and non-malignant respiratory disease were significant with rate ratios that increased monotonically with CFE. The model for deaths due to cardiovascular disease was also significant (rate ratio for CFE ≥44.0 f/cc-y vs <1.4 f/cc-y was 1.5; 95% confidence interval = 1.1 to 2.0). CONCLUSIONS: By using a within-cohort comparison, the results demonstrate a clear exposure-response relationship between CFE and mortality from asbestos-related causes. The finding of an association between CFE and cardiovascular mortality suggests persons exposed to Libby amphibole should be monitored for this outcome. |
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