1. Cardiopulmonary Disease Among Illinois Miners, Results of an Analysis of State Workers’ Compensation Data
K.S. Almberg1, L. Friedman1, J.M. Graber2, C. Rose3, E.L. Petsonk4, G. Harris2, L. Go1, L.T. Stayner1, R.A. Cohen1
1University of Illinois at Chicago, School of Public Health, Chicago, IL, 2Rutgers Environmental & Occupational Health Sciences Institute,
Piscataway, NJ, 3National Jewish Health, Denver, CO, 4West Virginia University, Morgantown, WV
Introduction
Results
Limitations
Miners in the U.S. suffer from excess chronic respiratory disease as well as other adverse health effects resulting from their occupational exposures. Acute injuries and fatalities from mining safety failures, as well as disease from mining-related occupational exposures, affect a large portion of the mining population and result in substantial impairment, disability, mortality, and compensation costs.
The utility of state-based data systems to assess the burden of respiratory and cardiovascular disease (CVD) in miners has not been fully explored. Workers’ compensation (WC) data may contain information about the prevalence of, and risk factors for, respiratory and cardiovascular injuries and illnesses in this population. We explored the utility and limitations of Illinois Workers’ Compensation Commission (IWCC) data for understanding respiratory and CVD trends in Illinois miners.
The U.S. Department of Labor, Mine Safety and Health Administration (MSHA) maintains mine-level data for all registered mines in the U.S. We explored the feasibility of linking the IWCC and MSHA data sets to assess associations between mining company characteristics and respiratory and CVD WC claims in Illinois.
IWCC Analysis:
12,582 mining-related claims in IWCC,
Significantly higher percentage of mining claimants
were male (97% vs. 70%), married (84% vs. 60%),
and over 45 years of age (62% vs. 38%) compared to
non-mining claimants (Table 1)
Significantly larger proportion of mining-related
claims involved the heart and/or lungs (13.7% vs. 0.5%),
respiratory system (2.7% vs. 0.1%), or were
categorized as pneumoconiosis than non-mining
related claims (p<.0001)
Mine employees had elevated odds of reporting an
illness or injury involving the heart and/or lungs
(OR 21.5, 95% CI 16.5 – 27.9), after controlling for
age and gender (Table 2)
IWCC and MSHA Analysis:
The number of mine employees declined from 15,745
to 6,921 during the study period (Figure 1)
Coal mine employees comprise 44 to 68% of all IL mine
employees, but 96% of mining-related claims in IWCC, from 1990−2010
Coal mine employees had significantly increased odds of reporting
a respiratory and/or cardiovascular injury/illness compared to
non-coal mine employees (Table 3)
Employees of small or medium mines had significantly increased
odds of reporting an injury/illness of the respiratory and/or
cardiovascular system
Mine employees of companies that have no safety committees at
any of their operated mines had increased odds of
respiratory/cardiovascular injuries and/or illnesses
IWCC data lacks information on race/ethnicity, tobacco use, and industry or occupation.
It is possible that not all mine employees in IWCC were correctly identified through the screening methodology employed in this study, resulting in potential exposure misclassification. However any such misclassification would have biased our findings toward the null hypothesis of no effect.
The lack of detailed occupational information made it impossible to discern miners from administrative or support staff working at mines.
The lack of information about place of injury in the IWCC data meant that the linkage was conducted at the company level, instead of the mine level.
There was considerable inconsistency in how injuries and illnesses of the respiratory and cardiovascular system were reported in the IWCC data. For example, the 36 reported cases of pneumoconiosis were classified across 4 different body parts and nature-of-injury classifications.
Methods
A U.S. underground coal miner changes bits on a continuous miner machine. Photo courtesy of Dr. Robert Cohen.
Data sources:
IWCC:
Mining-related claims from identified using a multi-step screening algorithm based on names of registered mining companies in Illinois, keywords (e.g. coal, silica, mining, quarry), and manual review
Includes contested claims only
Data elements include employee demographics, location of accident/injury, body part(s) affected, disability, and compensation awarded
Random sample of non-mining claims from selected as comparison group
MSHA:
Company level variables including average mine size, commodity (e.g coal, metal, non-metal), and the use of safety programs were created from publicly available Address/Employment and Mines databases
These data were linked with the IWCC data by year and company, and were assessed for their relationship with claims involving the heart and/or lungs in the IWCC data
Analyses:
Demographic and medical characteristics of claims in the IWCC were compared between employees of mining and non-mining industries.
1) IWCC analysis: The association between respiratory and CVD claims with mining employment in the IWCC data was characterized using logistic regression.
2) IWCC and MSHA analysis: The associations between respiratory and CVD claims and company characteristics among mine-employees in the IWCC data were explored using logistic regression.
All analyses were performed using SAS 9.4.
Conclusions
The finding of increased odds of injury and illness in small mines is consistent with those previously reported in the literature. A novel finding from this study, that may have practical implications for health and safety in mines, is that odds of respiratory and cardiovascular injury/illness were also higher in companies that lacked a safety committee at any of their operations. Lack of detailed health information in the IWCC data prevented analyses of individual respiratory or cardiovascular diseases.
This analysis underscores the importance of collecting industry and occupational information in WC claims as well as improving the injury/illness categorization to reduce misclassification of outcomes.
Further research is needed to identify additional company- and mine-level characteristics associated with respiratory and cardiovascular injuries and illnesses among miners.
Figure 1. Number of mine employees in Illinois from 1990 – 2010, by commodity.
Data source: MSHA Address/employment data.
This research was supported by a grant from the Alpha Foundation for the Improvement of Mine Safety and Health, Inc.