Mei-Lin Wang

Improvement in lung function measurements using a flow spirometer that emphasizes computer assessment of test quality.

We compared retrospective measurements of lung function from 101 steel workers using a commercially available spirometer to prospective lung function measurements performed, on average, 1.3 years later, with a newly developed spirometer. This spirometer was designed and developed to incorporate technology that provides immediate feedback on the quantitative and qualitative aspects of each forced expiratory effort. Of the 101 workers, 82 who had spirometry performed with each spirometer had at least two acceptable curves, and 51 workers tested with each spirometer had curves that met all American Thoracic Society (ATS) criteria for spirometry. No group showed the anticipated decline in forced expiratory volume in 1 second (FEV1) over time. The results showed an increased number of curves meeting ATS acceptability and reproducibility criteria, and a statistically significant increase in the FVC in all groups, and an increase in the FEV1 in the group encompassing all workers. Use of technology that strengthens the interaction between the spirometry technician, the data available to the technician on the computer, and the participant appears to represent true underlying lung function more accurately. Such an approach to the collection of lung function data should be considered by those evaluating spirometers for implementation in the workplace or pulmonary function laboratory as well as by those planning future spirometer development.

Chest illnesses and the decline of FEV1 in steelworkers

This study relates the impact of various medical conditions to clinically important forced expiratory volume in 1 second (FEV1) declines in a cohort of steelworkers evaluated cross-sectionally and longitudinally. Medical records of 1171 randomly chosen steelworkers were obtained from the medical department of a steel company. We reviewed the medical records for information regarding demographic parameters, smoking status, spirometry indexes, job history, and the workers respiratory health. These workers had performed annual spirometry from 1980 to 1991 at least once and up to 12 times. We compared the prevalence of medical conditions in 203 male never-smoking steelworkers in this group of 1171 workers by separating workers into three groups on the basis of final predicted FEV1 values (< 65%, between 65% and 79%, and > or = 80%). We also evaluated the prevalence of medical conditions and the association between these conditions and the rate of annual decline in FEV1 in 475 steelworkers who had at least three valid tests and at least 5 years separating the first and last test by multiple logistic regression analysis. Of the 475 steelworkers, 121 were categorized as rapid decliners (an annual rate of decline in FEV1 exceeding the 75th percentile of the slope distribution), whereas the remaining workers served as controls. Three of 203 and 17 of the remaining 200 in the cross-sectional survey had final predicted FEV1 values < 65% or between 65% and 79%, respectively. Among these 20 never-smokers, the accelerated rate of decline could be reasonably explained by factors independent of dust and age in all but two. In the 203 never-smokers, hay fever and trauma occurred more frequently in those with a decreased predicted FEV1. In the longitudinal study of 475 workers, the prevalence of pneumonia was significantly greater in the rapid decliners, whereas the prevalence of allergy, asthma or hay fever, and trauma approached a significant excess in number. Logistic regression models demonstrated that aging, weight gain, smoking, trauma, pneumonia, and a history of allergy, asthma, or hay fever were independently related to the risk of a clinically important decline of FEV1 in this group. In summary, there are multiple risk factors for an accelerated rate of decline in workers with dust exposure. An accurate assessment of the causes for an excessive rate of lung function decline in an individual worker within a population requires an understanding of the relationship between environmental exposures, lung function decline, and the individual workers underlying health. In addition to the three traditionally recognized variables--age, smoking, and dust exposure--the medical conditions of trauma, pneumonia, and allergy, asthma, or hay fever were related to a clinically important decline of FEV1 in this industrial population.

Rapid decline in forced expiratory volume in 1 second (FEV1) and the development of bronchitic symptoms among new Chinese coal miners.

Objective: To investigate the relationship between the development of bronchitic symptoms and the early rapid decline of forced expiratory volume in 1 second (FEV1). Methods: A two-stage and a mixed model approach were used to analyze data from 260 newly hired Chinese coal miners who completed approximately 5 to 16 health surveys during 3 years. Results: The proportion of miners with onset of bronchitic symptoms was significantly elevated after 11 months of underground mining. Miners with incident symptoms had greater declines in FEV1 compared with those who did not (−65 vs −23 mL/yr, P < 0.05). At 24 months follow-up, FEV1 had declined an average 235 mL among the 26 miners who developed bronchitic symptoms and smoked, compared with a decline of 96 mL among the 132 nonsmoking miners without symptoms. Conclusions: Among new coal miners, a sharp early decline in FEV1 is associated with the development of bronchitic symptoms.