The single breath nitrogen test in epidemiological surveys; an appraisal
article
The sensitivity to early srages of chronic non speoific lung disease (CNSLD) of 16 variables obtained with the single- and multiple-breath nitrogen tesr was studied in 554 men and 469 women in two cross-sectional surveys, and in ll8 conscripts. The reproducibilily of an index and ils potential to identify subjccts with abnormal lung functioí were judged jointly from the ratios of the between- and within-subject variances ol the indices, standardized for age and height. These ratios were highest for the slope of phase III in symptomatic and asymptomatic smoking men. Using discriminant analysis in both sexes the slope of phase III. and in men also residual volume. discriminates besl the asymptomatic smokers f,rom the non-smokers, and the asymptomatic from the symptomatic subjects; however, only 60 to 70 per cent of the subjects are correctly classified, showing the large overlap between groups. In men, the height of phase lV is larger in smokers than in nonsmokers. However, when adjusted for the slope of phase III, these differences disappear. The closing volume determination did not yield useful information in any of the analyses. Pack-years are more closely but poorly related to the age and height adjusted variables than daily cigarette consumption, indicating a predominantly cumulative dose-effect of smoking on lung function. The slope of phase III and residual volume, but not closing volume, are recommended for future use in longitudinal studies.
TNO Identifier
1000663
Source
Bulletin Européen de Physiopathologie Respiratoire, 17(3), pp. 381-397.
Pages
381-397
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