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Discriminating Measures and Normal Values for Expiratory Obstruction: Recommendation
There are several possible limitations in this study. Although the spirometric measurements followed ATS guidelines, it is possible that some subjects gave incomplete historical details. While we do not have data for Asian individuals or other ethnic groups, the similarity of FEV1/FVC and FEV3/FVC values among thousands of white, black, and Latin adults in the […]
Discriminating Measures and Normal Values for Expiratory Obstruction: Conclusion
In evaluating the cigarette-smoking effect in the NHANES III population, both the decreases in FEV1/FVC and increases in 1 — FEV3/FVC for a given age group are striking (Fig 3). Using either measurement, fractions progressively deteriorate with age relative to the never-smoking subjects. Consequently, by middle age current smokers have similar values to those of […]
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Discriminating Measures and Normal Values for Expiratory Obstruction: Discussion
Two prior studies have given reference values for FEV3/FVC. Each study used 200 to 300 nonsmoking white adults of northern European ethnicity. Over a broad age and height range, our mean FEV3/FVC values for white never-smokers are, on average, approximately 1.7% and 1.0% lower than those for men and women reported in the study by […]
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Discriminating Measures and Normal Values for Expiratory Obstruction: Results
A total of 1,167 (ie, the sum of values from lines b to n, Table 3) of 3,570 smokers had abnormal patterns. Eight hundred one smokers had expiratory obstruction; 66% of smokers (530 of 801 smokers) [lines d to f, Table 3] had both early and late expiratory obstruction with or without possible restriction; 16% […]
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Discriminating Measures and Normal Values for Expiratory Obstruction: Physiologic Defects in Current Smokers
Figure 2 shows marked differences in the variability of FEV1/FVC, FEV3/FVC, and FEF25-75 in never-smokers and current smokers for each fifth percentile of the respective populations when plotted against the percentage of the mean predicted values. The legend emphasizes misclassifications that would result if 80% of mean values was used as the threshold. Figure 3 […]
Discriminating Measures and Normal Values for Expiratory Obstruction: Pattern Analysis of Current Smokers
We placed each of the currently smoking subjects into 1 of 16 (24) potential categories, depending on whether or not their FEVi, FVC, FEV/FVC, and FEV3/FVC values were below the LLN. This allowed us to decide whether each subject had normal spirometry findins, or had a pattern of obstruction, had probable restriction, or a combination, […]
Discriminating Measures and Normal Values for Expiratory Obstruction: Subjects
Utilizing data from the same NHANES III source, we did the following: (1) calculated the mean and LLN values for FEV3/FVC in these never-smoking and currently smoking groups; (2) compared the variability of FEV1/FVC, FEV3/FVC, and FEF25-75 values in never-smokers and current smokers; and (3) assessed changes associated with aging and smoking. We hypothesized that […]
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