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1.
Environ Res ; 230: 114578, 2023 08 01.
Article in English | MEDLINE | ID: mdl-36965797

ABSTRACT

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. Dr. Taioli indicated that the epidemiology evidence concerning non-asbestiform EMPs is weak or lacking, and that progress would be limited unless mesothelioma registries are established. One exception discussed is that of taconite miners, who are exposed to grunerite. Drs. Mandel and Odo noted that studies of taconite miners in Minnesota have revealed an excess rate of mesothelioma, but the role of non-asbestiform EMPs in this excess incidence of mesothelioma is unclear. Dr. Becich discussed the National Mesothelioma Virtual Bank (NMVB), a virtual mesothelioma patient registry that includes mesothelioma patients' lifetime work histories, exposure histories, biospecimens, proteogenomic information, and imaging data that can be used in epidemiology research on mesothelioma. Dr. Bernstein indicated that there is a strong consensus that long, highly durable respirable asbestiform EMPs have the potential to cause mesothelioma, but there is continued debate concerning the biodurability required, and the dimensions (both length and diameter), the shape, and the dose associated with mesothelioma risk. Finally, Dr. Nel discussed how experimental studies of High Aspect Ratio Engineered Nanomaterials have clarified dimensional and durability features that impact disease risk, the impact of inflammation and oxidative stress on the epigenetic regulation of tumor suppressor genes, and the generation of immune suppressive effects in the mesothelioma tumor microenvironment. The session ended with a discussion of future research needs.


Subject(s)
Air Pollutants, Occupational , Asbestos , Lung Neoplasms , Mesothelioma , Occupational Exposure , Humans , Epigenesis, Genetic , Lung Neoplasms/chemically induced , Lung Neoplasms/epidemiology , Minerals/analysis , Mesothelioma/chemically induced , Mesothelioma/epidemiology , Asbestos/toxicity , Tumor Microenvironment
2.
Ann Work Expo Health ; 66(4): 459-471, 2022 04 22.
Article in English | MEDLINE | ID: mdl-34864842

ABSTRACT

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)]. Within each department, we applied a two-level random-intercept regression model which assumes that the natural log of Y (RD or RS concentration) changes over time at a constant rate. Among all predicted RD and RS values, we found that larger RD values were located in the following departments: Crushing, Concentrating, Pelletizing, and Shop (mobile). Larger RS values were located only in either Crushing or Shop (mobile). The annual rates of change for historical RD and RS exposures were between -3.3 and 3.2%. The silica percentage in the dust varied by mine/department with the highest value of 29.3% in Mine F (Crushing) and the lowest value of 2.1% in Mine B (Pelletizing). The predicted historical RD and RS arithmetic mean exposures ranged between <0.075 and 3.14 mg m-3, and between <0.005 and 0.36 mg m-3, respectively. The result of this study is a JEM by mine, department, and year for RD and RS for epidemiological studies.


Subject(s)
Air Pollutants, Occupational , Occupational Exposure , Air Pollutants, Occupational/analysis , Dust/analysis , Humans , Iron , Mining , Occupational Exposure/analysis , Silicates , Silicon Dioxide/analysis
3.
Ann Work Expo Health ; 64(9): 993-1006, 2020 11 16.
Article in English | MEDLINE | ID: mdl-33196824

ABSTRACT

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. The final CFs allow the creation of job exposure matrices (JEMs) for alternative EMP metrics using existing EMP exposures already characterized according to the National Institute of Occupational Safety and Health (NIOSH)-defined EMP exposure metric (length >5 µm with an aspect ratio ≥3.0). The relationships between the NIOSH EMP and other EMP definitions provide the basis of classification of workers into JEMs based on alternate definitions of EMP for epidemiological studies of mesothelioma, lung cancer, and non-malignant respiratory disease.


Subject(s)
Air Pollutants, Occupational , Bayes Theorem , Occupational Exposure , Air Pollutants, Occupational/analysis , Humans , Minerals , Minnesota , Occupational Exposure/analysis
4.
Int Arch Occup Environ Health ; 93(1): 77-85, 2020 01.
Article in English | MEDLINE | ID: mdl-31372718

ABSTRACT

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. Current and historical occupational exposure assessments were obtained, the former measuring about 679 personal samples over the period of the study for respirable dusts, including silica, in 28 major job functions. Cumulative silica exposure ((mg/m3) × years) was estimated as a cumulative product of time worked and year-specific silica job exposure concentrations. Chest x-ray abnormalities were based on B-reader agreement with a third B-reader for arbitration. Forced vital capacity (FVC) less than lower limits of normal for age, height, race and gender was used to determine spirometric restrictive ventilatory defect (RVD). Prevalence ratios (PR) of exposure-outcome associations, with 95% confidence intervals (CI), were estimated using multivariate Poisson regression. RESULTS: Cumulative silica exposure was associated with RVD prevalence (PR = 1.41, 95% CI = 1.09-1.81) and prevalence of parenchymal abnormalities on chest x-ray (PR = 1.30, 95% CI = 1.00-1.69) using exposure estimates based primarily on current study measurements, and assuming unchanged historical exposure trend. Conversely, when exposures were defined incorporating available actual historical values, no associations were observed between silica exposure and either RVD (PR = 0.76, 95% CI = 0.41-1.40) or parenchymal (PR = 0.87, 95% CI = 0.45-1.70) outcomes. CONCLUSIONS: This study demonstrated that the estimated association between silica dust exposure and lung disease is highly sensitive to the approach used to estimate cumulative exposure. Cumulative values based on conservative estimates of past exposure, modeled from recently measured respirable silica, showed an association with restriction RVD on spirometry. Silica exposure was also significantly associated with increased parenchymal findings on chest x-ray using this approach. Conversely, these findings were absent when actual available historical data was used to estimate cumulative silica exposure. These differences highlight the challenges with estimating occupational dust exposure, the potential impact on calculated exposure risk and the need for long term quality exposure data gathering in industries prone to risk from inhaled respirable dusts.


Subject(s)
Iron , Miners , Occupational Exposure/analysis , Respiratory Tract Diseases/epidemiology , Silicates , Silicon Dioxide/adverse effects , Aged , Cross-Sectional Studies , Dust , Female , Humans , Male , Middle Aged , Minnesota , Occupational Diseases/epidemiology , Occupational Exposure/adverse effects , Radiography, Thoracic , Respiratory Tract Diseases/diagnostic imaging , Retrospective Studies , Spirometry , Vital Capacity
5.
J Occup Environ Hyg ; 16(12): 817-826, 2019 12.
Article in English | MEDLINE | ID: mdl-31647751

ABSTRACT

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. After data treatment, all data were grouped into seven mines and eight departments. Within each mine-department, the yearly EMP mean concentration in f/cc for each year of operation was predicted using two approaches. The performance of two approaches varied by situation. The assumptions underlying each approach described in this article have limitations. A linear regression based on limited historical measurements and those made in 2010-2011 (Approach 1) does not yield reasonable and plausible values of the slope. Approach 2 assumes that the EMP and the respirable dust in the same department share the same historical time trend. This approach allowed us to avail of the more reasonable slope estimates from the historical respirable dust data set and yielded more plausible historical exposure estimates for most locations. This work with two different job exposure matrix (JEMs) provides a unique research opportunity to study the potential impact of exposure assessment to epidemiological results. Both JEMs are being used to assess associations between EMP and respiratory disease in epidemiological studies.


Subject(s)
Air Pollutants, Occupational/analysis , Dust/analysis , Iron , Minerals/analysis , Mining/history , Occupational Exposure/analysis , Silicates , History, 20th Century , History, 21st Century , Humans , Minnesota , National Institute for Occupational Safety and Health, U.S. , Occupational Exposure/history , United States
7.
Ann Surg ; 270(2): 302-308, 2019 08.
Article in English | MEDLINE | ID: mdl-29697454

ABSTRACT

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. METHODS: Multicenter, prospective study of patients with pathologic acid reflux confirmed by esophageal pH testing undergoing MSA. Predefined clinical outcomes were assessed at the annual visit including a validated, disease-specific questionnaire, esophagogastricduodenoscopy and esophageal pH monitoring, and use of proton pump inhibitors. RESULTS: A total of 200 patients (102 males, 98 females) with a mean age of 48.5 years (range 19.7-71.6) were treated with MSA between March 2013 and August 2015. At 1 year, the mean total acid exposure time decreased from 10.0% at baseline to 3.6%, and 74.4% of patients had normal esophageal acid exposure time (% time pH<4 ≤5.3%). GERD Health-Related Quality of Life scores improved from a median score of 26.0 at baseline to 4.0 at 1 year, with 84% of patients meeting the predefined success criteria of at least a 50% reduction in total GERD Health-Related Quality of Life score compared with baseline. The device removal rate at 1 year was 2.5%. One erosion and no serious adverse events were reported. CONCLUSIONS: Safety and effectiveness of magnetic sphincter augmentation has been demonstrated outside of an investigational setting to further confirm MSA as treatment for GERD.


Subject(s)
Deglutition/physiology , Esophageal Sphincter, Lower/surgery , Gastroesophageal Reflux/surgery , Magnets , Adult , Aged , Esophageal Sphincter, Lower/physiopathology , Esophageal pH Monitoring , Female , Follow-Up Studies , Gastroesophageal Reflux/metabolism , Gastroesophageal Reflux/physiopathology , Humans , Male , Middle Aged , Prospective Studies , Prosthesis Design , Surveys and Questionnaires , Time Factors , Treatment Outcome , Young Adult
8.
Ann Work Expo Health ; 63(1): 77-90, 2019 01 07.
Article in English | MEDLINE | ID: mdl-30351393

ABSTRACT

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. We then took air samples at 91 fixed locations using an array of direct-reading instruments to obtain measurements of mass (PM2.5 or particles with aerodynamic diameter <2.5 µm, and respirable particulate matter or RPM), alveolar-deposited surface area (ADSA), and particle number (PN) concentrations. At each location, a respirable gravimetric pump (which was used for calibration purposes) and the instruments measured the ambient dust level for 4 h producing ~240 1-min averaging real-time measurements. To analyze these data, we fit a Bayesian hierarchical model with an autoregressive order 1 correlation structure to estimate pooled concentrations for the 16 work areas/buildings while accounting for temporal correlation. PM2.5 and RPM average ambient concentrations were highly correlated to each other (Pearson's correlation = 0.98), followed by ADSA and PN correlation (R = 0.77). Office and control room areas were found to have the lowest concentrations in all four metrics when compared to other groups. Distinguishing between concentration levels among the remaining groups was more difficult due to the high uncertainty associated with the geometric mean estimates. The geometric standard deviation within location (GSDWL) generally ranged from 1 to 3 for all exposure metrics, except for a few locations that may have had changes in the work activities that generated the observed peaks and variability during the sampling duration. The geometric standard deviation between locations estimates were generally higher than GSDWL, which may indicate larger variability in the processes/activities between locations within each broad work area/building. Future work may look into whether it is feasible to use area measurements for epidemiological investigation and use personal measurements (if available) to validate such approach.


Subject(s)
Aerosols/analysis , Air Pollutants/analysis , Environmental Monitoring/methods , Iron , Mining , Occupational Exposure/analysis , Silicates , Bayes Theorem , Benchmarking , Dust/analysis , Humans , Particle Size , Particulate Matter/analysis
9.
Toxicol Appl Pharmacol ; 361: 107-112, 2018 12 15.
Article in English | MEDLINE | ID: mdl-29653125

ABSTRACT

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. Geologic sampling has indicated that only the eastern part of the iron range contains non-asbestiform amphibole elongate mineral particles (EMPs), in close proximity to the ore. This type of EMP has been less studied and also exists in talc and gold mining. A series of investigations into the state's taconite industry have been recently completed. Results from a cohort mortality study indicated an SMR of 2.77 (95% CI = 1.87-3.96) for mesothelioma. In a case-control study, the odds ratio for mesothelioma for high vs. low EMP exposure was 2.25 (5% CI = 1.13-4.5) but EMPs in this study were counted by phase contrast microscopy. Odds ratios were not elevated in mines located in the eastern part of the Mesabi iron range. The overall findings suggest that mesothelioma in taconite miners is related to EMP exposure. Because of the way EMPs were counted, results from these studies cannot allow a firm conclusion about the association between EMP exposure and the reported excess mesothelioma.


Subject(s)
Air Pollutants, Occupational/toxicity , Iron , Lung Neoplasms/chemically induced , Mesothelioma/chemically induced , Minerals/toxicity , Mining , Occupational Diseases/chemically induced , Occupational Exposure/adverse effects , Particulate Matter/toxicity , Silicates , Case-Control Studies , Cohort Studies , Cross-Sectional Studies , Health Surveys , Humans , Incidence , Lung Neoplasms/epidemiology , Lung Neoplasms/mortality , Mesothelioma/epidemiology , Mesothelioma/mortality , Minnesota/epidemiology , Occupational Diseases/epidemiology , Occupational Diseases/mortality , Occupational Exposure/statistics & numerical data , United States/epidemiology
10.
Am J Ind Med ; 61(5): 391-399, 2018 05.
Article in English | MEDLINE | ID: mdl-29516526

ABSTRACT

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. Participants provided an occupational history and had a chest radiograph performed. RESULTS: A total of 1188 workers participated. Potential exposures to non-amphibole EMPs were evident across multiple jobs in all active mines. Pleural abnormalities were found in 16.8% of workers. There was an association of pleural abnormalities with cumulative EMP exposure that was not specific to the eastern portion of the range. CONCLUSION: There was evidence of a mild to moderate increase in pleural abnormalities in this population of miners, associated with geographically non-specific cumulative EMP exposure.


Subject(s)
Iron/adverse effects , Occupational Diseases/chemically induced , Occupational Diseases/epidemiology , Occupational Exposure/adverse effects , Pleural Diseases/chemically induced , Pleural Diseases/epidemiology , Silicates/adverse effects , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Environmental Monitoring/methods , Female , Humans , Male , Middle Aged , Mining , Minnesota/epidemiology , Occupational Diseases/diagnostic imaging , Pleural Diseases/diagnostic imaging , Regression Analysis , Risk Factors
11.
J Occup Environ Hyg ; 14(5): 377-388, 2017 05.
Article in English | MEDLINE | ID: mdl-28388309

ABSTRACT

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. Between-mine, between-SEG (similar exposure groups), within-SEG, and within-worker components of variability for RD and RS exposures were estimated using a two- or three-way nested random-effects ANOVA model. The majority of RD concentrations across all mines were below the Mine Safety and Health Administration (MSHA) Permissible Exposure Limit (PEL). The highest concentrations of RD were often observed in either the Pelletizing or Crushing departments, which are inherently dusty operations. With a few exceptions, the concentrations of RS in the crushing and concentrating processes were higher than those in the other mining processes, as well as higher than the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) for RS. The magnetic separation and flotation processes in the concentrating department reduced the levels of RS significantly, and lowered the percentage of quartz in RD in the pelletizing department. There was little variability among the six mines or between the two mineralogically distinct zones for either RD or RS exposures. The between-SEG variability for RS did not differ substantially across most of the mines and was a major component of exposure variance. The within-SEG (or between-worker) variance component was typically the smallest because in many instances one worker from a SEG within a mine was monitored multiple times. Some of these findings were affected by the degree of censoring in each SEG and mine, characteristics of the taconite rock, seasonal effects during sampling, or the tasks assigned to each job in that mine.


Subject(s)
Dust/analysis , Environmental Monitoring , Iron/chemistry , Mining , Occupational Exposure/analysis , Silicates/chemistry , Silicon Dioxide/analysis , Occupational Health
12.
Am J Ind Med ; 59(12): 1047-1060, 2016 12.
Article in English | MEDLINE | ID: mdl-27699808

ABSTRACT

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. RESULTS: Quantitative EMP exposure information in these industries is incomplete. However, there are consistent findings of pneumoconiosis in each of these types of mining. A recent case-control study suggests a possible association between this exposure and mesothelioma. Lung cancer is inconsistently reported in these industries and is an unlikely outcome of non-asbestiform EMP exposure. There is evidence of cardiovascular mortality excess across all of these types of mining. CONCLUSIONS: Non-malignant respiratory disease and cardiovascular mortality have been consistently increased in these industries. Further investigation, including additional insights for the role of non-asbestiform EMP, is warranted. Am. J. Ind. Med. 59:1047-1060, 2016. © 2016 Wiley Periodicals, Inc.


Subject(s)
Air Pollutants, Occupational/toxicity , Minerals , Mining , Occupational Diseases/mortality , Occupational Exposure/adverse effects , Cardiovascular Diseases/etiology , Cardiovascular Diseases/mortality , Gold , Humans , Iron , Mesothelioma/etiology , Mesothelioma/mortality , Occupational Diseases/etiology , Particle Size , Pneumoconiosis/etiology , Pneumoconiosis/mortality , Silicates , Talc
13.
J Occup Environ Med ; 58(2): 154-61, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26849259

ABSTRACT

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. Demographic, exposure, and injury data collected for four 6-month periods used a computer-assisted telephone interview. An a priori causal model enabled survey development, data analysis, and interpretation. Directed acyclic graphs, developed from this model, facilitated potential confounder identification for specific exposures in multivariate analyses. RESULTS: The injury rate was 12.82 events per 1000 persons per year. Increased risk was associated with male gender, increasing age, state of residence, history of prior injury, and increasing hours worked per week. CONCLUSIONS: Large machinery-related agricultural injuries can result in significant consequences. Associated increased injury risks require further investigation and targeting of relevant interventions.


Subject(s)
Accidents, Occupational/statistics & numerical data , Agriculture/instrumentation , Occupational Injuries/etiology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Databases, Factual , Female , Health Surveys , Humans , Male , Middle Aged , Midwestern United States/epidemiology , Multivariate Analysis , Occupational Injuries/epidemiology , Risk Factors , Young Adult
14.
Chem Res Toxicol ; 29(2): 136-41, 2016 Feb 15.
Article in English | MEDLINE | ID: mdl-26756500

ABSTRACT

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. The understanding of respiratory disease in taconite mining is hampered by the lack of exposure data to asbestiform mineral fibers that occurred in the 1950s and 1960s. Other industries with similar mineral exposure have not demonstrated definitive associations with respiratory cancer, although non-malignant respiratory disease is a consistent finding in epidemiological studies.


Subject(s)
Air Pollutants, Occupational/toxicity , Inhalation Exposure , Iron/toxicity , Lung Neoplasms/etiology , Mesothelioma/etiology , Mining , Silicates/toxicity , Air Pollutants, Occupational/chemistry , Humans , Iron/chemistry , Lung Neoplasms/mortality , Mesothelioma/mortality , Occupational Exposure , Silicates/chemistry , Survival Analysis
15.
Occup Environ Med ; 73(2): 103-9, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26655961

ABSTRACT

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. METHODS: Mesothelioma cases (N=80) were identified through the Minnesota Cancer Surveillance System (MCSS) and death certificates. Four controls of similar age were selected for each case with 315 controls ultimately eligible for inclusion. Mesothelioma risk was evaluated by estimating rate ratios and 95% CIs with conditional logistic regression in relation to duration of taconite industry employment and cumulative EMP exposure [(EMP/cc)×years], defined by the National Institute for Occupational Safety and Health (NIOSH) 7400 method. Models were adjusted for employment in haematite mining and potential exposure to commercial asbestos products used in the industry. RESULTS: All mesothelioma cases were male and 57 of the cases had work experience in the taconite industry. Mesothelioma was associated with the number of years employed in the taconite industry (RR=1.03, 95% CI 1.00 to 1.06) and cumulative EMP exposure (RR=1.10, 95% CI 0.97 to -1.24). No association was observed with employment in haematite mining. CONCLUSIONS: These results support an association between mesothelioma and employment duration and possibly EMP exposure in taconite mining and processing. The type of EMP was not determined. The potential role of commercial asbestos cannot be entirely ruled out.


Subject(s)
Iron/adverse effects , Lung Neoplasms/etiology , Mesothelioma/etiology , Mining , Occupational Diseases/etiology , Occupational Exposure/adverse effects , Particulate Matter/adverse effects , Silicates/adverse effects , Adult , Air Pollutants, Occupational/adverse effects , Case-Control Studies , Employment , Female , Ferric Compounds/adverse effects , Humans , Logistic Models , Lung Neoplasms/mortality , Male , Mesothelioma/mortality , Minerals , Minnesota/epidemiology , Occupational Diseases/mortality , Risk Factors , Work
16.
Ann Epidemiol ; 25(11): 811-5, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26381550

ABSTRACT

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. SIRs for lung cancer by histologic subtypes were also estimated. We adjusted for out-of-state migration and conducted a probabilistic bias analysis for smoking-related cancers. RESULTS: A total of 5700 cancers were identified, including 51 mesotheliomas and 973 lung cancers. The SIRs for lung cancer and mesothelioma were 1.3 (95% CI = 1.2-1.4) and 2.4 (95% CI = 1.8-3.2), respectively. Stomach, laryngeal, and bladder cancers were also elevated. However, adjusting for potential confounding by smoking attenuated the estimates for lung (SIR = 1.1, 95% CI = 1.0-1.3), laryngeal (SIR = 1.2, 95% CI = 0.8-1.6), oral (SIR = 0.9, 95% CI = 0.7-1.2), and bladder cancers (SIR = 1.0, 95% CI = 0.8-1.1). CONCLUSIONS: Taconite workers may have an increased risk for certain cancers. Lifestyle and work-related factors may play a role in elevated morbidity. The extent to which mining-related exposures contribute to disease burden is being investigated.


Subject(s)
Iron/adverse effects , Mining , Neoplasms/epidemiology , Occupational Diseases/epidemiology , Occupational Exposure/adverse effects , Silicates/adverse effects , Adult , Age Distribution , Air Pollutants, Occupational , Cohort Studies , Female , Humans , Incidence , Inhalation Exposure , Male , Middle Aged , Minnesota/epidemiology , Occupational Exposure/statistics & numerical data , Public Health Surveillance , Sex Distribution , United States/epidemiology , Young Adult
17.
Front Med ; 9(3): 392-400, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26089192

ABSTRACT

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. This fraction has been associated with increasing rates of cardio-respiratory disease in China and elsewhere. Ambient pollutant levels have been described in many of China's cities and are comparable to previous levels in southern California. Lung cancer mortality in China has increased since the 1970s and has been higher in men and in urban areas, the exact explanation for which has not been determined. The estimation of individual risk for Chinese citizens living in areas of air pollution will require further research. Occupational cohort and case-control designs each have unique attributes that could make them helpful to use in this setting. Other important future research considerations include detailed exposure assessment and the possible use of biomarkers as a means to better understand and manage the threat posed by air pollution in China.


Subject(s)
Air Pollutants/classification , Air Pollution/adverse effects , Environmental Exposure/adverse effects , Lung Neoplasms/mortality , Research Design/trends , China/epidemiology , Humans , Incidence , Rural Population/statistics & numerical data , Sex Distribution , Urban Population/statistics & numerical data
18.
AIDS Behav ; 19(10): 1938-40, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26070886

ABSTRACT

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. These findings indicate a need to improve the quality of data on reported mode of HIV transmission. Accurate information has important public health implications in planning prevention and treatment services.


Subject(s)
HIV Infections/epidemiology , HIV Infections/transmission , Heterosexuality , Homosexuality, Male , Population Surveillance/methods , Adult , Drug Users/statistics & numerical data , Female , HIV Infections/prevention & control , Humans , Incidence , Male , Risk Factors , Risk-Taking , Substance Abuse, Intravenous/epidemiology , Ukraine/epidemiology
19.
Occup Environ Med ; 72(9): 633-9, 2015 Sep.
Article in English | MEDLINE | ID: mdl-25977445

ABSTRACT

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. Two age-matched controls were selected from risk sets of cohort members alive and lung cancer free at the time of case diagnosis. Calendar time-specific exposure estimates were made for every job and were used to estimate workers' cumulative exposures. ORs and 95% CIs were estimated using conditional logistic regression. We evaluated total lung cancer risk and risk of histological subtype by total work duration and by cumulative EMP, and silica exposure by quartile of the exposure distribution. RESULTS: A total of 1706 cases and 3381 controls were included in the analysis. After adjusting for work in haematite mining, asbestos exposure and sex, the OR for total duration of employment was 0.99 (95% CI 0.96 to 1.01). The ORs for quartile 4 versus 1 of EMP and silica exposure were 0.82 (95% CI 0.57 to 1.19) and 0.97 (95% CI 0.70 to 1.35), respectively. The risk of each histological subtype of lung cancer did not change with increasing exposure. CONCLUSIONS: This study suggests that the estimated taconite mining exposures do not increase the risk of developing lung cancer.


Subject(s)
Air Pollutants, Occupational , Iron , Lung Neoplasms/etiology , Mining , Occupational Diseases/etiology , Occupational Exposure/analysis , Silicates , Silicon Dioxide , Aged , Aged, 80 and over , Air Pollutants, Occupational/adverse effects , Asbestos/adverse effects , Case-Control Studies , Employment , Humans , Iron/adverse effects , Logistic Models , Minnesota , Occupational Exposure/adverse effects , Odds Ratio , Risk Factors , Silicates/adverse effects , Silicon Dioxide/adverse effects
20.
Chem Res Toxicol ; 28(3): 319-24, 2015 Mar 16.
Article in English | MEDLINE | ID: mdl-25622246

ABSTRACT

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. Future studies that define individual exposures, combined with biomarkers linked to disease, will be essential to the understanding of risk posed by air pollution in China.


Subject(s)
Air Pollution/adverse effects , Environmental Exposure/adverse effects , Particulate Matter/adverse effects , Biomarkers , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/prevention & control , China , Humans , Respiratory Tract Diseases/epidemiology , Respiratory Tract Diseases/prevention & control
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