Comparison between reference values for FVC, FEV1, and FEV1/FVC ratio in White adults in Brazil and those suggested by the Global Lung Function Initiative 2012

Objective: To evaluate the spirometry values predicted by the 2012 Global Lung Function Initiative (GL1) equations, which are recommended for international use, in comparison with those obtained for a sample of White adults used for the establishment of reference equations for spiromety in Brazil. Methods: The sample comprised 270 and 373 healthy males and females, respectively. The mean differences between the values found in this sample and the predicted values calculated from the GL1 equations for FVC, FEV1, and VEF1/FVC, as well as their lower limits, were compared by paired t-test. The predicted values by each pair of equations were compared in various combinations of age and height. Results: For the males in our study sample, the values obtained for all of the variables studied were significantly higher than those predicted by the GL1 equations (p < 0.01 for all). These differences become more evident in subjects who were shorter in stature and older. For the females in our study sample, only the lower limit of the FEV1/FVC ratio was significantly higher than that predicted by the GL1 equation. Conclusions: The predicted values suggested by the GL1 equations for White adults were significantly lower than those used as reference values for males in Brazil. For both genders, the lower limit of the FEV1/FVC ratio is significantly lower than that predicted by the GL1 equations.