Table 3—

Prediction equations from the Bronchial Obstruction in North Trøndelag (BONT) study for particular parameters with explained variance (adjusted R2) and residual standard deviation (RSD) based on 362 males and 546 females

MalesFemales
ParameterEquationR2RSDEquationR2RSD
FVCExp (−12.396+2.733 ln(H)−0.0000592 A2)0.630.12Exp (−9.851+2.189 ln(H)−0.000143A2+0.006439A0.680.13
FEV1Exp (−10.556+2.342 ln(H)−0.0000685 A2)0.600.12Exp (−9.091+2.004 ln(H)−0.000163 A2+0.007237A0.720.13
FEV1/FVCExp (6.433−0.385 ln(H)−0.000923A)0.050.07Exp (5.403−0.185ln(H)−0.00115A)0.060.07
PEF L·s−1Exp (−6.632+1.731 ln(H)−0.000436A2)0.160.23Exp (−7.726+1.808 ln(H)−0.000286A2+0.022A)0.340.25
FEF25%–75% L·s−1Exp (−3.764+1.037 ln(H)−0.000102A2)0.260.27Exp (−6.442+1.474 ln(H)−0.000243A2+0.01199A)0.410.30
Log AUC L× L·s−1Exp (−156.16+37.12ln(H)−0.184H−0.00012A2)0.510.27Exp (−16.597+3.698 ln(H)−0.00041A2+0.02408A)0.650.29
  • A: age in yrs

  • H: height in cm

  • Exp (x): ex

  • FVC: forced vital capacity

  • FEV1: forced expiratory volume in one second

  • PEF: peak expiratory flow

  • FEF25%–75%: forced mid-expiratory flow

  • AUC: area under curve

  • The predicted value for FEV1 in a 20 yrs-old man with height 180 cm is computed as: FEV1= e(−10.556 + 2.342×ln(180) – 0.0000685×400) = e1.5785 =4.848

  • The lower limit of normal (LLN) is computed as: LLN FEV1 = e(predicted−1.645×RSD) = e1.3811 = 3.979