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worker wearing respirator, lab worker, lungs

Inputs: Emerging Issues

Use of Digital Chest Imaging in Occupational Health Settings

Chest radiography has been an important tool in medical screening and surveillance for occupational lung disease since the first half of the 20th century. The system adopted worldwide for assessing the presence and severity of changes in chest radiographs consistent with pneumoconioses was the “International Labour Organization (ILO) Classification of Radiographs of Pneumoconioses,” In the U.S., the ILO classification system is used in a range of settings and its use is required in various governmental and compensation settings. The ILO classification system specifies that film-based chest radiographs must be used for classification. This has recently created challenges in the U.S., where digital chest imaging has replaced film-based chest radiography in most clinical settings. Digital chest imaging provides many advantages, including more efficient image distribution, storage and retrieval; elimination of hazardous chemicals used to develop films; and the potential for advanced image processing and automated image interpretation. However, challenges remain that must be addressed to allow replacement of film-based chest radiographs with digital chest images in occupational settings, including documentation of equivalency, development of technical guidelines to assure consistent, high quality of results, and, for intramural NIOSH programs, updating infrastructure to accommodate use of digital chest imaging in teaching, testing, and service activities.

Flavorings-Related Lung Disease

Inhalation of butter flavoring chemical mixtures, including the chemical diacetyl, has been associated with severe obstructive lung disease. Many people with this disease who have been studied with lung biopsy have been found to have an irreversible type of lung damage called constrictive bronchiolitis. In this condition, the smallest airways carrying air through the lungs, the bronchioles, become scarred and constricted. This disease has now been described in a variety of work settings where diacetyl and butter flavorings are present, including microwave popcorn production plants, flavoring production plants, a chemical plant where diacetyl was made, and several other food production settings. The Occupational Safety and Health Administration (OSHA) has recently published an advanced notice of proposed rulemaking on occupational exposure to diacetyl and food flavorings containing diacetyl, which will need to be supported by a strong scientific foundation in toxicology, field studies and epidemiology, exposure assessment, engineering controls, and personal protective equipment.

Coal Workers’ Pneumoconiosis (CWP)

CWP, commonly referred to as “black lung,” is a fibrosing lung disease caused by inhalation of coal mine dust. Although it can be prevented by reducing inhalation of coal mine dust, it continues to be a significant problem. In the period from 1995-2005, it was listed as causing or contributing to 9642 deaths. Its prevalence in long-term miners who participate in national x-ray surveillance has recently increased, and advanced CWP has been identified among miners in their 30s and 40s. Risk for progressive CWP appears to be greatest in certain geographic “hot spots,” particularly the Appalachian region. In view of these issues, and the projected increase in coal mining, CWP must be viewed as an emerging issue despite its long history. New tools are being applied to prevent CWP. In 2009, the Mining Safety and Health Administration (MSHA) requested comments on a proposed rule to allow the use of real-time monitors to measure exposure of coal miners to respirable coal mine dust. Completing this rule and promoting widespread use of the monitors may allow miners to immediately detect and control exposures. Research is underway to assess adequacy of engineering controls in hot spot regions and recommend improvements. Finally, to utilize x-ray machines now present in most clinical settings, it is important that guidance be developed to allow use of digital chest imaging in place of film-based radiographs in CWP health screening programs.

Occupational Respiratory Disease Surveillance

Injury and illness surveillance is a fundamental activity for ongoing assessment of adverse occupational outcomes, providing the foundation for research, evaluation, and prevention efforts. Without surveillance data, the effectiveness of any intervention or prevention program cannot be assessed. However, there is a critical lack of reliable and comprehensive national morbidity and mortality surveillance data for occupational respiratory disease (ORD) outcomes, especially by workplace exposure or its surrogates. Surveillance for occupational respiratory disease can be very difficult because there is often a delay of many years between occupational exposures and development of disease. Often, diseases do not manifest themselves until after affected individuals have left the offending jobs or even retired. Thus, making the link between occupation, industry, and disease often requires a statistical approach. In the past, death certificate information provided important, ongoing statistical information about the relationships between decedents’ usual industry or occupation and cause of death. Unfortunately, since 2000, this has not been possible because most states have not coded usual industry or occupation into analyzable electronic death certificate data bases. Thus, developing new approaches to occupational respiratory disease surveillance is an important, emerging issue. Efforts are underway to address this issue by developing methods for automated coding of occupation and industry. If successful, these efforts would allow coding of death certificate data, restoring them as a useful source of occupational respiratory disease surveillance. In addition, it will be important to identify and use new sources of surveillance information, such as workers’ compensation records, health insurance information, and electronic health records. Electronic health records are, in theory, very attractive because they will be widely used and will provide information about a range of disease types.