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NIOSH Respiratory Diseases Research Program

Evidence Package for the National Academies' Review 2006-2007

NIOSH Programs > Respiratory Diseases > Evidence Package > 4. Airways Diseases > 4.1 Work-Related Asthma

4.1d) Improve Ascertainment of the Asthma-Work Association

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Issue

Asthma can be caused or exacerbated by exposures in the ambient environment, at home, or at work. Improved methods are needed to ascertain that asthma is related to exposures at work. The 1978 version of the American Thoracic Society’s “Adult Respiratory Questionnaire” has been used hundreds of times by researchers conducting epidemiologic research on airways diseases, both in the U.S. and dozens of other countries. By the late 1990s, this questionnaire was dated and especially needed new questions relevant to asthma and occupational exposures. The Asthma and COPD NORA Team recognized the need for modifying this widely used standard questionnaire, as summarized in “The Team Document: Ten Years of Leadership Advancing NORA” (A4-47).

An RDRP scientist developed a new portable spirometer in the late 1980s. It was a fully functional spirometer for measuring and recording the standard features of pulmonary function and was designed to be worn on a workers belt. It also recorded and date- and time-stamped all of its readings, which overcame the problem of subjects having to do so. Also, unlike other portable devices that measured only peak expiratory flow, this new device measured most of the standard metrics of pulmonary function, including Forced Expiratory Volume in One Second (FEV1) and the forced vital capacity. This NIOSH “belt spirometer” was used in HHEs where asthma was an outcome of interest. This “belt spirometer” served a purpose in demonstrating the feasibility of fully functional portable electronic recording spirometers, and helped spawn interest in the development of improved portable spirometry instrumentation and related software for use in serial spirometry testing for asthma.

Approach

Since 2001, two RDRP scientists have participated as members of the American Thoracic Society ad hoc committee to revise the “Adult Respiratory Questionnaire.” The other scientists and clinicians on the same ad hoc committee are from academia and NIH in the U.S., as well as from other countries. In 2001, RDRP and the American Thoracic Society co-sponsored a meeting of the committee. It included meetings devoted to occupational exposures and outcomes. In subsequent meetings, RDRP members of the committee successfully argued for the inclusion of more questions on occupation. In addition, they led the revision of a more extensive occupational module that could be used in conjunction with the core Adult Questionnaire. The first version of the instrument was completed by 2003, at which time RDRP contracted with CDC’s National Center for Health Statistics (NCHS) to conduct cognitive testing of the new questions. Based on the cognitive testing report, the committee made changes in the core questionnaire. In 2005, RDRP contracted again with NCHS, to conduct cognitive testing of the revised core questionnaire plus the occupational components.

New technologies were developed for portable spirometers by private companies in the late 1990s. RDRP developed hardware and software to facilitate the collection of serial spirometry data that can be used to confirm suspected work-related changes in pulmonary function. Part of this work was done by RDRP and part was done in collaboration with a spirometry equipment manufacturer. RDRP scientists worked with the ndd Corporation to modify existing spirometer software to keep track of serial testing of subjects. This represented an advance in assessment and documentation for a commercially available, portable, electronic recording spirometer easy enough to be used by unsupervised, ambulatory individuals. In 2002 and 2003, the Workplace Exacerbation of Asthma project used EasyOne™ portable spirometers from ndd Corporation to conduct serial testing of adults with asthma to detect patterns of variable airflow consistent with workplace exacerbation of asthma. The new device and software were also used in several HHEs that involved asthma.

Outputs and Transfers

The first NCHS report from cognitive review was available late in 2004, and was used to further revise the core Adult Questionnaire. A report from the second round of cognitive testing was released in September 2006.

The software developed by RDRP in collaboration with the ndd Corporation for the EasyOne™ portable spirometer has been retained by the company.

Intermediate Outcomes

RDRP-developed “belt spirometers” were loaned to state-based SENSOR asthma surveillance programs and academic occupational health researchers (e.g. at Duke University). The software has been used by researchers in Michigan in a study of WRA (A4-48).

The software developed by RDRP in collaboration with the ndd Corporation for the EasyOne™ portable spirometer is offered to customers as one of the software packages that can be used with the EasyOne™. Thus, clinicians and researchers now have ready access to the EasyOne™ as a tool for detecting variability in lung function in the ambulatory setting, an important approach to detecting WRA.

What’s Ahead

In 2007, cognitive testing of the revised adult respiratory questionnaire will be completed. During 2008, the test data will be used to modify the parts of the questionnaire related to occupational exposures, symptoms, and diseases. RDRP will also conduct field testing of the questionnaire, either by extramural funding or by an internal field study. The questionnaire, including the occupational module, will then be published by the Society. Researchers and clinicians will be able to use the instrument in their work, and hopefully it will have a 10 to 20 year life span for research purposes (in its almost 30-year life span, the 1978 questionnaire has been used widely throughout the world in respiratory health studies).

In the coming year, RDRP will also develop criteria for interpreting serial peak expiratory flow measurements and evaluate serial spirometry data collected in the study of workplace exacerbation of asthma. These studies will describe and compare peak expiratory flow and FEV1 and serial measurements for peak expiratory flow and FEV1 to standard office spirometry. They will also compare the performance of peak expiratory flow and FEV1 for identifying workplace exacerbation of asthma.

Intermediate Goal and Objectives Moving Forward

The RDRP intermediate goal is to contribute to the reduction and prevention of WRA. This will be accomplished through the following objectives:

  • Monitoring the frequency of natural rubber latex asthma among healthcare workers to ensure the problem remains under control
  • Using the EasyOne™ spirometer with the software developed by RDRP scientists in several investigations of WRA
  • Developing better tools for identification, evaluation, and prevention of WRA
  • Developing recommendations for identification, evaluation, and prevention of WRA, including WRA associated with indoor environmental quality problems
  • Facilitating prevention of WRA through the effective dissemination and assisting implementation of recommendations