Abstract
BACKGROUND: Healthy individuals without respiratory symptoms can sometimes present with low FEV1/FVC. The objective of this study was to characterize and compare subjects without symptoms and with reduced FEV1/FVC but normal FEV1 with subjects with mild obstructive lung disease.
METHODS: Fifty healthy subjects with FEV1/FVC below the fifth percentile of reference values (normal variants) were compared with 52 subjects with asthma and 48 subjects with COPD who had similar FEV1/FVC.
RESULTS: Subjects without symptoms were more likely to be male, younger, and taller, and to have higher FVC%, FEV1%, mid expiratory flow, and terminal flow than subjects with obstructive disease. A receiver operating characteristic curve analysis determined that the best separation between the groups was provided by age < 55 y, height ≥ 167 cm, and FVC > 105%. A logistic regression analysis confirmed that male sex, age, FVC%, and FEF75 (Forced expiratory flow in 75% of forced vital capacity) were significant factors for discriminating subjects without symptoms from those with obstructive lung disease.
CONCLUSIONS: A reduced FEV1/FVC may be a normal finding in younger-to-middle age male subjects with an FVC% value above the mean predicted value, especially when terminal flow is within the normal range.
- airway obstruction
- asthma
- chronic obstructive pulmonary disease
- expiratory flow
- lung function
- lung functions testing
- spirometry
Footnotes
- Correspondence: Luciana dos Santos Andreata, 62 Santo Afonso St, Sete Lagoas, MG 35701-135 Brazil. E-mail: luluandreata{at}gmail.com.
The authors have disclosed no conflicts of interest.
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