Effects of Age on 1-Second Forced Expiratory Volume Response to Bronchodilation

Summary 

Background

The bronchodilation test is used to detect reversible airways obstruction, considered important for diagnosing asthma. However, little is known about the effects of age on the bronchodilation response. The aim of this study was to evaluate the effects of age on the bronchodilation response by determining changes in the 1-second forced expiratory volume (FEV₁) in a Chinese population.

Methods

All patients underwent pulmonary function testing to evaluate forced vital capacity, peak expiratory flow, and FEV₁. We assessed bronchodilation by measuring the change in FEV₁ (ΔFEV₁) before and after inhalation of 0.4mg of fenoterol (two puffs) delivered by a metered-dose inhaler with a spacer.

Results

Of the 1,616 patients tested in the clinic, the 333 (21%) who had a positive bronchodilator test, defined as ΔFEV₁ > 12% and 200mL, were enrolled in the study. For this population, the ΔFEV₁ was +360.8 ± 138.6mL (mean ± standard deviation) or + 21.0% ± 9.1%. In a multiple linear regression model, the absolute ΔFEV₁ (expressed in milliliters) was independently and negatively predicted by age (p < 0.001), and baseline peak expiratory flow (p < 0.001), but positively predicted by height (p < 0.001).

Conclusion

Age was an important determinant for response to bronchodilation as determined by the absolute change in FEV₁.

Key Words:  asthma , bronchodilators , lung function tests , spirometry

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