Prediction equations for spirometry in four- to six-year-old children

Objective To generate prediction equations for spirometry in 4- to 6-year-old children. Methods Forced vital capacity, forced expiratory volume in 0.5 s, forced expiratory volume in one second, peak expiratory flow, and forced expiratory flow at 25–75% of the forced vital capacity were assessed in 195 healthy children residing in the town of Sete Lagoas, state of Minas Gerais, Southeastern Brazil. The least mean squares method was used to derive the prediction equations. The level of significance was established as p < 0.05. Results Overall, 85% of the children succeeded in performing the spirometric maneuvers. In the prediction equation, height was the single predictor of the spirometric variables as follows: forced vital capacity = exponential [(−2.255) + (0.022 × height)], forced expiratory volume in 0.5 s = exponential [(−2.288) + (0.019 × height)], forced expiratory volume in one second = exponential [(−2.767) + (0.026 × height)], peak expiratory flow = exponential [(−2.908) + (0.019 × height)], and forced expiratory flow at 25–75% of the forced vital capacity = exponential [(−1.404) + (0.016 × height)]. Neither age nor weight influenced the regression equations. No significant differences in the predicted values for boys and girls were observed. Conclusion The predicted values obtained in the present study are comparable to those reported for preschoolers from both Brazil and other countries.