13. Vision for the Future12. Sampling and Analytical Methods Activities
The mission of RDRP is “to provide national and international leadership for the prevention of work-related respiratory diseases, using a scientific approach to gather and synthesize information, create knowledge, provide recommendations, and deliver products and services to those who can effect prevention.” Embodied in this mission statement is the recognition that RDRP cannot prevent work-related respiratory diseases on its own. But RDRP can play a key role by motivating and enabling others to make their own unique contributions. RDRP will continue to evaluate and re-evaluate a range of data inputs to ensure that its research and other activities remain relevant to customer needs and to document impact. Inputs used by RDRP will include surveillance data, information from Health Hazard Evaluation and Technical Assistance requests and findings, stakeholder input, economic data, information reported in the scientific literature and input from others that is relevant to occupational respiratory disease. We will also use information obtained from the Evaluation Committee through its evaluation of RDRP, as well as stakeholder comment stimulated by dissemination of chapter contents via the NIOSH Web site and the NIOSH eNews.
RDRP has shaped a preliminary vision for its future program of research and other activities within NIOSH’s new matrix management structure. This structure stretches across all of NIOSH’s traditional administrative units. RDRP is inclusive of the broad range of individuals and groups supported by NIOSH to do work that is relevant to occupational respiratory disease. A degree of overlap exists between RDRP and other elements of the matrix management structure, including two scheduled to undergo National Academies reviews of their own (the Cancer Program and the Personal Protective Technology Program). Detailed presentation of those programs and their plans will be provided during their reviews. Plans presented here focus specifically on the work-related respiratory diseases, themselves.
RDRP has developed five strategic goals. Four are based on disease category. One is based on exposure, since it is currently unknown if that exposure will induce respiratory or other work-related disease. The strategic goals of RDRP are to:
Although these strategic goals are primarily organized by disease process, many types of activities are embodied within the strategic goals. Multidisciplinary research, surveillance, development of authoritative recommendations, health communications, and training and education are all of critical importance in preventing and reducing work-related respiratory disease and all will be used to achieve RDRP goals.
The terminology “prevent and reduce” may seem redundant. But it was chosen intentionally, because the existence of reduction can be objectively measured. The existence of prevention, to some degree, must be assumed.
Each individual strategic goal is briefly discussed below.
Strategic Goal 1: Prevent and reduce work-related airways diseases
This goal is of very high priority due to the large numbers of people who are affected by these diseases and the financial cost to society. Earlier in this document, it was noted that the American Thoracic Society has estimated that 15 percent of COPD and adult asthma are attributable to workplace exposures, with a conservative annual estimated cost in the U.S. of nearly $7 billion.
WRA remains a very challenging problem. It can be caused or exacerbated by a large variety of occupational agents in a wide range of work-places, including non-industrialized indoor workplaces. Symptoms of WRA may occur outside of work hours, such as after work or during the weekend, making them difficult to associate with workplace exposure. RDRP will work to improve characterization, exposure assessment, and elucidation of mechanisms of action for two types of agents that remain poorly characterized, low molecular weight agents and mold allergens. Asthma associated with nonindustrialized indoor workplaces is one of the more common complaints cited by requestors of HHEs. Although recommendations exist for remediation of these indoor environments, little is known about effectiveness. RDRP will investigate the effectiveness of such recommendations made in conjunction with HHEs to mitigate asthma associated with indoor air/environmental quality. RDRP will implement and monitor a model screening and surveillance program for WRA in the isocyanate manufacturing industry, anticipating that this model program could provide lessons transferable not only downstream to isocyanate users but also to other industrial sub-sectors in which workers are exposed to other asthma-causing agents. Finally, together with others, RDRP will continue to develop and validate better approaches to facilitate use of ambulatory spirometry for assessment of asthma at work.
RDRP will work to elucidate the nature, causes, and prevention of work-related diseases associated with chronic airways obstruction. RDRP will work to increase awareness of the contribution of occupational exposures to the burden of COPD. RDRP will continue to develop data sets that can be used to evaluate relationships between prevalence of COPD and occupation. RDRP will partner with other agencies to enhance the value of data from the NHANES in documenting the burden of occupational COPD. In addition, approaches for assessment of longitudinal lung function decline as a method for early detection of COPD in individual workers will be developed. RDRP will disseminate these findings as guidance to enhance workplace spirometry monitoring programs. In recent years, serious problems have emerged with severe fixed airways obstruction associated with bronchiolitis obliterans in workers exposed to artificial butter flavorings. RDRP plans to aggressively pursue surveillance for this condition to better understand the extent, severity, and cause(s) of the problem. RDRP will conduct studies to better understand the inhalation toxicology of artificial butter flavorings. RDRP will continue to partner with California’s OSHA and Department of Health Services to assess a number of facilities and develop protective recommendations for exposure assessment and engineering controls. Finally, RDRP will work to provide regulators with the data they need to address current requests for Emergency Temporary Standards for diacetyl; and the data and risk assessments they will need for worker protection over the long term.
Strategic Goal 2: Prevent and reduce work-related interstitial lung diseases
Protection against coal worker’s pneumoconiosis through reduction of respirable coal mine dust exposures by 50 percent before 2014 is a key performance measure in the OMB PART used to rate NIOSH’s performance as a federal program (A1-2). Unfortunately, RDRP has recently identified clusters of miners with progressive massive fibrosis in Appalachia, suggesting continued problems with excessive exposure to coal mine dust. Further reductions in coal mine dust exposure will be sought through continuing technological improvements in dust assessment and dust control in coal mining. RDRP activities will include working to assure the availability and widespread use of personal dust monitors that can signal excursion from the PEL in real-time. In cooperation with a major manufacturer of roof bolting machines, RDRP will demonstrate the effectiveness of a canopy air curtain system that will reduce roofbolters’ respirable dust exposures by at least 40 percent. The current ILO classification system used in surveillance for CWP requires use of traditional film-based chest radiographs. The capability to take such radiographs is becoming increasingly rare in the U.S. due to the market dominance of digital radiography. RDRP will address this inevitable transition by introducing digital chest imaging standards for classification of pneumoconiosis. RDRP will seek and investigate the nature and causes of "hot spots" of pneumoconiosis observed among coal miners. This effort will be supported by RDRP’s already operational mobile examination unit, which will increasingly serve hard-to-reach communities of coal miners. RDRP will explore with MSHA strategies that could lead to achievement in coal mining of the NIOSH REL of 1 mg/m3 proposed in 1995.
Exposure to silica dust, especially freshly fractured, silicaceous material, is associated with development of silicosis and lung cancer. In addition, there is evidence for an association with kidney diseases, autoimmune disorders, and other adverse health effects. RDRP will work to reduce exposures to crystalline silica in the construction industry and to reduce exposures through abrasive blasting. Work performed by RDRP to introduce standards for use of digital chest radiographs to classify for changes associated with pneumoconiosis will also have relevance to medical screening and surveillance for silicosis. The potential usefulness of molecular biomarkers for early detection will also be investigated. Although silicosis has become less common in the U.S., it remains a frequent and difficult problem internationally, particularly in the developing world. RDRP will continue to partner internationally to establish models of national silicosis surveillance, incorporating best practices from systems used in U.S. and other countries, adapted to local needs and infrastructure. RDRP will assist its international partners in developing local expertise in using the ILO classification system for radiographs of the pneumoconioses, as well as in performing spirometry. It will further help to establish sustainable educational and local accreditation systems in these countries.
Despite the implementation of an occupational exposure limit of 2 μg/m3 TWA by OSHA, workers in the beryllium industry still become immunologically sensitized to beryllium and develop chronic beryllium disease. Several years ago, based on RDRP observations, our industry partner (Brush Wellman) introduced a Comprehensive Preventive Program that included dermal protection. RDRP is assisting Brush Wellman to monitor that program for its effectiveness and to make adjustments as necessary. Ultimately, RDRP will conduct a follow-up study of all current and former workers hired under Brush Wellman’s Comprehensive Preventive Program to determine the program’s long-term effectiveness in reducing sensitization and chronic beryllium disease.
RDRP will complete ongoing epidemiologic analyses of data collected from 1998-2005, using exposure estimates constructed from historical mass-based airborne beryllium sampling data to assess for exposure-response relationships. Because simple mass-based exposure metrics may not optimally predict risk for development of chronic beryllium disease, RDRP will also collect new data that will allow it to reanalyze the epidemiologic data collected from 1998-2005 and examine dose-response relationships in light of estimated dissolved beryllium dose and categorical dermal exposure. In addition, a variety of genetic markers are being studied and gene-environment interaction analyses for the adverse outcomes of sensitization and disease will be performed. These analyses will take into account estimated mass-based beryllium exposure, estimated dissolved beryllium dose, and categorical dermal exposure. RDRP will make transgenic mice expressing human HLA molecules associated with risk for chronic beryllium disease available to researchers. These mice will be used in studies that examine the impacts of beryllium dose and form; and route, pattern and duration of exposure on development of sensitization and pulmonary pathology consistent with experimental chronic beryllium disease.
Strategic Goal 3: Prevent and reduce work-related respiratory infectious diseases
Several infectious diseases pose current risk and/or potential future threat to workers, including: pandemic influenza, because it can be readily transmitted to healthcare and other workers from infectious patients or coworkers; TB, because it can be readily transmitted to healthcare and other workers in close contact with infectious patients or coworkers; and anthrax, because of continued terrorist activity and the large social and economic impact of the anthrax terrorist attacks in the U.S. several years ago. Additional emerging diseases such as avian influenza and SARS are also important concerns. RDRP will continue to contribute to the high priority, federal government-wide effort to develop and improve recommendations, raise awareness, and prepare for outbreaks of pandemic or avian influenza. RDRP will work to sustain the decline in TB incidence in the U.S. through development of improved engineering controls to prevent TB transmission in healthcare and correctional settings, and through development and dissemination of culturally and linguistically appropriate education materials concerning occupational TB targeted to high risk settings. RDRP will work to reduce vulnerability of workers to bioterrorism by maintenance of preparedness to deal with terror attacks. RDRP will also contribute to risk reduction relating to potential future chemical, biological, radiological, and nuclear threats through improvements in its OMB PART key performance measure of increasing the percent of fire fighters and first responders with access to CBRN respirators. In addition, development of TIL standards and research on face shape will drive the development of respirators with better “out-of-the-box” fitting characteristics. Finally, research on respirator re-use will help to ease shortages in the event of an emergency such as outbreak of pandemic influenza.
Strategic Goal 4: Prevent and reduce work-related respiratory malignancies
Work-related respiratory cancer is a high priority problem. As noted in chapter 5, it has been estimated that approximately 9,000-10,000 men and 900-1,900 women develop lung cancer annually in the U.S. due to past exposure to occupational carcinogens. Efforts to reduce exposures to crystalline silica, now generally accepted as a respiratory carcinogen, have already been discussed. Over the next several years, efforts will focus on two additional respiratory carcinogens, diesel exhaust and mineral fibers.
In the case of diesel exhaust, efforts will focus on completion of the collaborative NIOSH and NCI epidemiological study of diesel exhaust and mortality, which focuses on lung cancer as an outcome. This large study will provide important information about relationships between diesel exhaust exposure and lung cancer. It will be especially useful in documenting exposure-response relationships. Research will also focus on developing exposure assessment methods and control technologies to facilitate implementation of MSHA’s diesel rule.
Relationships between mineral fiber exposures and chest malignancies such as lung cancer and mesothelioma will be another important focus of investigation. Asbestos is a well-known carcinogen. However, current exposure-response relationships for induction of respiratory cancer are based on exposure methods using older light microscopy-based methods. Current work is using electron microscopy- based methods to reanalyze the exposures of a cohort of asbestos textile workers. This will allow modeling of exposure-response that takes into account the vast majority of fibers that cannot be seen by light microscopy. Another study will evaluate cancer mortality in a cohort of vermiculite miners exposed to the asbestiform amphibole fibers contaminating vermiculite from Libby, MT. This reanalysis includes and expands upon a cohort first studied in the 1980s and, given the latencies between exposure and development of cancer, will likely detect steeper exposure-response relationships than the original study. Finally, RDRP will conduct laboratory-based studies to evaluate the impact of various fiber characteristics on carcinogenesis, including length, biopersistence, crystallization pattern (asbestiform vs. massive), and mineral composition. These studies are very much needed to understand the carcinogenic potential of mineral fibers other than asbestos, especially so-called “cleavage fragments” composed of massive amphibole.
Strategic Goal 5: Prevent respiratory and other diseases potentially resulting from occupational exposures to nanomaterials.
Nanotechnology is advancing rapidly. Respiratory diseases resulting from inhalation of nanoparticles or other diseases resulting from migration of inhaled nanoparticles through the lungs to other organs have yet to emerge in nanotechnology workers. However, there is sufficient potential to require that the possibility of nanoparticle-induced diseases be anticipated and addressed. RDRP believes that it is important to understand the potential risks posed by nanoparticles and nanomaterials and ways to protect exposed workers. RDRP will determine relative toxicities of different nanomaterials in biological systems. RDRP will conduct research to develop and validate methods of exposure assessment. RDRP will consider and recommend appropriate periodic medical monitoring and surveillance of exposed or potentially exposed workers. RDRP will consider and recommend appropriate engineering controls for workplaces where nanomaterials are manufactured and used; these will include administrative controls, chemical safety hoods, HVAC systems and filtration, and appropriate personal protective technologies.
In summary, RDRP planning is influenced by a range of inputs. Historical and legally mandated responsibilities (diseases induced by coal-mine dust), surveillance and epidemiological data (asthma, COPD, respiratory malignancies), opportunities to prevent emerging diseases (flavorings-induced bronchiolitis obliterans, new asthma agents, emerging infectious diseases), and scientific imperatives (nanotechnology, chronic beryllium disease) all play important roles in guiding RDRP planning. The institute can bring to bear an array of resources to achieve its goals, the most important being the multidisciplinary collaborations which are so important to advances in research and applied prevention. RDRP strategic plans will evolve as goals are accomplished, surveillance changes priorities, and novel approaches and problems arise in U.S. and global workplaces. RDRP effectiveness in preventing work-related respiratory disease will depend on a cogent and organized approach to priority setting. This approach must allocate the resources committed by the Institute and society for occupational respiratory diseases research in a way that assures optimal relevance and impact.