Non-asbestiform elongate mineral particles and mesothelioma risk: Human and experimental evidence.

The presentations in this session of the Monticello II conference were aimed at summarizing what is known about asbestiform and non-asbestiform elongate mineral particles (EMPs) and mesothelioma risks based on evidence from experimental and epidemiology studies. Dr. Case discussed case reports of mesothelioma over the last several decades.

Reconstructing Historical Exposures to Respirable Dust and Respirable Silica in the Taconite Mining Industry for 1955-2010.

The goal of this study was to reconstruct the historical respirable silica (RS) and respirable dust (RD) exposures of workers in the Minnesota taconite industry from 1955 to 2010 as part of several epidemiological studies for assessing the association between exposure to components of taconite dusts and the development of respiratory diseases. A job-exposure matrix (JEM) was developed that uses 9127 RS and 19 391 RD occupational hygiene historical measurements. Historical RS and RD data were extracted from several sources and were grouped into seven mines and then into eight departments [Concentrating, Crushing, Janitor, Mining, Office/control room, Pelletizing, Shop (mobile), and Shop (stationary)].

A Bayesian Approach for Determining the Relationship Between Various Elongate Mineral Particles (EMPs) Definitions.

A variety of dimensions (lengths and widths) of elongate mineral particles (EMPs) have been proposed as being related to health effects. In this paper, we develop a mathematical approach for deriving numerical conversion factors (CFs) between these EMP exposure metrics and applied it to the Minnesota Taconite Health Worker study which contains 196 different job exposure groups (28 similar exposure groups times 7 taconite mines). This approach comprises four steps: for each group (i) obtain EMP dimension information using ISO-TEM 10312/13794 analysis; (ii) use bivariate lognormal distribution to characterize overall EMP size distribution; (iii) use a Bayesian approach to facilitate the formation of the bivariate lognormal distribution; (iv) derive conversion factors between any pair of EMP definitions.

Reconstructing historical exposures to elongate mineral particles (EMPs) in the taconite mining industry for 1955-2010.

As part of ongoing epidemiological studies for assessing the association between exposure to dust from taconite operations and the development of respiratory diseases, the goal of this study was to reconstruct the exposures of workers to elongate mineral particle (EMP) in the Minnesota taconite mining industry from 1955-2010. Historical NIOSH-7400 and equivalent EMP personal exposure data were extracted from two sources: (1) the Mine Safety and Health Administration (MSHA) online database recorded for all inspection results since 1978 with 655 EMP monitoring records from 1978-2010 for 13 MSHA Mine IDs associated with this study; and (2) the mining companies' internal monitoring reports contained 96 personal EMP exposure records. NIOSH-7400 EMP personal exposures were measured for workers in different jobs in all active mines in 2010 by obtaining 1,285 personal samples.

The impact of different approaches to exposure assessment on understanding non-malignant respiratory disease risk in taconite miners.

Introduction: We examined the association between cumulative silica exposures in taconite mining and non-malignant respiratory disease (NMRD) using a comprehensive assessment of current and historical exposure measurements in a cross-sectional study of Minnesota taconite mining workers. We also explored the impact of exposure measurement methods by comparing estimated exposure risk from two different exposure measurement modeling approaches.

Methods: Miners were screened with an occupational and medical history questionnaire, spirometry testing and chest x-rays per ILO guidelines.

Ambient Fine Aerosol Concentrations in Multiple Metrics in Taconite Mining Operations.

Studies in environmental epidemiology and of occupational cohorts have implicated the effects of fine particulates with increased risk of cardiovascular diseases. Motivated by this evidence, we conducted an ambient air monitoring campaign to characterize fine aerosol concentrations around various taconite ore processes in six taconite mines in northeastern Minnesota. The ore processes were first categorized into 16 broad work areas/buildings.

Objective Evidence of Reflux Control After Magnetic Sphincter Augmentation: One Year Results From a Post Approval Study.

Objective: To report 1-year results from a 5-year mandated study.

Summary Background Data: In 2012, the United States Food and Drug Administration approved magnetic sphincter augmentation (MSA) with the LINX Reflux Management System (Torax Medical, Shoreview, MN), a novel device for the surgical treatment of gastroesophageal reflux disease (GERD). Continued assessment of safety and effectiveness has been monitored in a Post Approval Study.

Mesothelioma and other lung disease in taconite miners; the uncertain role of non-asbestiform EMP.

The purpose of this paper was to assess the role of non-asbestiform amphibole EMPs in the etiology of mesotheliomas and other lung disease in taconite (iron ore) miners. Increased mesothelioma rates have been described in Minnesota taconite workers since the late 1990s. Currently, over 100 cases have been reported by the Minnesota Department of Health within the complete cohort of miners in Minnesota.

Pleural abnormalities and exposure to elongate mineral particles in Minnesota iron ore (taconite) workers.

Background: Iron ore (taconite) mining and processing are an important industry in northern Minnesota and western Michigan. Concerns around exposures have centered largely on exposure to non-asbestiform amphibole elongate mineral particles (EMPs) found in the eastern portion of the Minnesota iron range.

Methods: A cross sectional survey was undertaken of current and former taconite workers and spouses along with a detailed exposure assessment.

A comprehensive assessment of exposures to respirable dust and silica in the taconite mining industry.

This study assessed the present-day levels (year 2010-2011) of exposure to respirable dust (RD) and respirable silica (RS) in taconite mines and evaluated how the mining process influences exposure concentrations. Personal samples (n = 679) were collected to assess exposure levels of workers to RD and RS at six mines in the Mesabi Iron Range of Minnesota. The RD and RS concentrations were measured using the National Institute for Occupational Safety and Health (NIOSH) 0600 and NIOSH 7500, respectively.

A review of mortality associated with elongate mineral particle (EMP) exposure in occupational epidemiology studies of gold, talc, and taconite mining.

Background: Mining of gold, taconite, and talc may involve exposure to elongate mineral particles (EMP). The involved EMPs are typically non-asbestiform, include dimensions that regulatory definitions exclude, and have been less studied.

Methods: A review of the literature was undertaken for this exposure and occupational epidemiological studies that occur in gold, talc, and taconite mining.

Large Machinery-Related Agricultural Injuries Across a Five-State Region in the Midwest.

Objective: High agricultural injury related mortality and morbidity rates persist. This study addressed a knowledge gap regarding large machinery-related injury magnitude, consequences, and risk factors.

Methods: From randomly selected Midwestern agricultural operations in 1999 and 2001, 7420 eligible households participated.

Increased Lung Cancer Mortality in Taconite Mining: The Potential for Disease from Elongate Mineral Particle Exposure.

Taconite mining involves potential exposure to non-asbestiform amphibole mineral fiber. More recent studies have demonstrated increased mortality from respiratory cancers and heart disease among workers in the taconite industry. This finding is not consistent with recent exposure assessment findings, nor is the toxicology of this mineral suggestive of neoplastic disease.

A case-control study of mesothelioma in Minnesota iron ore (taconite) miners.

Objectives: An excess of mesothelioma has been observed in iron ore miners in Northeastern Minnesota. Mining and processing of taconite iron ore generate exposures that include elongate mineral particles (EMPs) of amphibole and non-amphibole origin. We conducted a nested case-control study of mesothelioma in a cohort of 68,737 iron ore miners (haematite and taconite ore miners) to evaluate the association between mesothelioma, employment and EMP exposures from taconite mining.

Cancer incidence among Minnesota taconite mining industry workers.

Purpose: To evaluate cancer incidence among Minnesota taconite mining workers.

Methods: We evaluated cancer incidence between 1988 and 2010 in a cohort of 40,720 Minnesota taconite mining workers used between 1937 and 1983. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were estimated by comparing numbers of incident cancers with frequencies in the Minnesota Cancer Surveillance System.

Burnout and Physical Activity in Minnesota Internal Medicine Resident Physicians.

Background: Regular physical activity plays an important role in the amelioration of several mental health disorders; however, its relationship with burnout has not yet been clarified.

Objective: To determine the association between achievement of national physical activity guidelines and burnout in internal medicine resident physicians.

Methods: A Web-based survey of internal medicine resident physicians at the University of Minnesota and Hennepin County Medical Center was conducted from September to October 2012.

Ambient air pollution and lung disease in China: health effects, study design approaches and future research.

Ambient air pollution in China has worsened following dramatic increases in industrialization, automobile use and energy consumption. Particularly bothersome is the increase in the PM2.5 fraction of pollutants.

Misclassification of men with reported HIV infection in Ukraine.

We analyzed data on reported mode of transmission in case reports of HIV-infections among men in Ukraine. The number of men who were reported to have acquired HIV through heterosexual transmission increased substantially in 2006-2011. However, we estimate that up to 40 % of reported cases of heterosexual transmission among men may actually represent misclassified men who have sex with men or persons who inject drugs.

Occupational exposures and lung cancer risk among Minnesota taconite mining workers.

Objective: To examine the association between employment duration, elongate mineral particle (EMP) exposure, silica exposure and the risk of lung cancer in the taconite mining industry.

Methods: We conducted a nested case-control study of lung cancer within a cohort of Minnesota taconite iron mining workers employed by any of the mining companies in operation in 1983. Lung cancer cases were identified by vital records and cancer registry data through 2010.

Increasing fine particulate air pollution in China and the potential use of exposure and biomarker data in disease prevention.

Increased industrialization and urbanization have led to marked increases in air pollutants in China over the last decade. Pollutant levels in the north and eastern regions are often four times higher than current daily levels in the United States. Recent reports indicate a higher incidence of lung cancer and mortality in men and urban dwellers, but the contribution of air pollution to these findings remains unknown.

Mortality experience among Minnesota taconite mining industry workers.

Objective: To evaluate the mortality experience of Minnesota taconite mining industry workers.

Methods: Mortality was evaluated between 1960 and 2010 in a cohort of Minnesota taconite mining workers employed by any of the seven companies in operation in 1983. Standardised mortality ratios (SMR) were estimated by comparing observed deaths in the cohort with expected frequencies in the Minnesota population.

The relationship between various exposure metrics for elongate mineral particles (EMP) in the taconite mining and processing industry.

Different dimensions of elongate mineral particles (EMP) have been proposed as being relevant to respiratory health end-points such as mesothelioma and lung cancer. In this article, a methodology for converting personal EMP exposures measured using the National Institute for Occupational Safety and Health (NIOSH) 7400/7402 methods to exposures based on other size-based definitions has been proposed and illustrated. Area monitoring for EMP in the taconite mines in Minnesota's Mesabi Iron Range was conducted using a Micro Orifice Uniform Deposit Impactor (MOUDI) size-fractionating sampler.