This position statement reviews several aspects of spirometric testing in the workplace, where spirometry is employed in the primary, secondary, and tertiary prevention of occupational lung disease. Primary prevention includes pre-placement and fitness-for-duty examinations as well as research and monitoring of health status in groups of exposed workers; secondary prevention includes periodic medical screening of individual workers for early effects of exposure to known occupational hazards; and tertiary prevention includes clinical evaluation and impairment/disability assessment. For all of these purposes, valid spirometry measurements are critical, requiring: documented spirometer accuracy and precision, a rigorous and standardized testing technique, standardized measurement of pulmonary function values from the spirogram, adequate initial and refresher training of spirometry technicians, and, ideally, quality assessment of samples of spirograms. Interpretation of spirometric results usually includes comparison with predicted values and should also evaluate changes in lung function over time. Response to inhaled bronchodilators and changes in relation to workplace exposure may also be assessed. Each of these interpretations should begin with an assessment of test quality and, based on the most recent ATS recommendations, should rely on a few reproducible indices of pulmonary function (FEV1, FVC, and FEV1/FVC.) The use of FEF rates (e.g., the FEF25-75%) in interpreting results for individuals is strongly discouraged except when confirming borderline airways obstruction. Finally, the use of serial PEF measurements is emerging as a method for confirming associations between reduced or variable pulmonary function and workplace exposures in the diagnosis of occupational asthma. Throughout this position statement, ACOEM makes detailed recommendations to ensure that each of these areas of test performance and interpretation follow current recommendations/standards in the pulmonary and regulatory fields. Submitted by the Occupational and Environmental Lung Disorder Committee on November 16,1999. Approved by the ACOEM Board of Directors on January 4,2000.

An industry-wide pulmonary morbidity study was undertaken to evaluate the respiratory health of employees manufacturing refractory ceramic fibers at five US sites between 1987 and 1989. Refractory ceramic fibers are man-made vitreous fibers used for high temperature insulation. Of the 753 eligible current employees, 742 provided occupational histories and also completed the American Thoracic Society respiratory symptom questionnaire; 736 also performed pulmonary function tests. Exposure to refractory ceramic fibers was characterized by classifying workers as production or nonproduction employees and calculating the duration of time spent in production employment. The risk of working in the production of refractory ceramic fibers and having one or more respiratory symptoms was estimated by adjusted odds ratios and found to be 2.9 (95 percent confidence interval 1.4-6.2) for men and 2.4 (95 percent confidence interval 1.1-5.3) for women. The effect of exposure to refractory ceramic fibers on forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), the ratio of the two (FEV1/FVC), and forced expiratory flow (liters/second) between 25 percent and 75 percent of the FVC curve (FEF(25-75)) was evaluated by multiple regression analysis using transformed values adjusted for height, by dividing by the square of each individual's height. For men, there was a significant decline in FVC for current and past smokers of 165.4 ml (p < 0.01) and 155.5 ml (p = 0.04), respectively, per 10 years of work in the production of refractory ceramic fibers. For FEV1, the decline was significant (p < 0.01) only for current smokers at 134.9 ml. For women, the decline was greater and significant for FVC among nonsmokers, who showed a decrease of 350.3 ml (p = 0.05) per 10 years of employment in the production of refractory ceramic fibers. These findings indicate that there may be important sex differences in response to occupational and/or environmental exposure.

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Noncombat injuries and illnesses have had a significant impact on military missions and continue to result in force health protection challenges today. Future studies are needed to test and evaluate countermeasures to mitigate these illnesses and injuries to increase the health of the individuals and optimize mission readiness.