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Table 3 Derived equations for various spirometric parameters of male and female subjects

From: Reference equations for spirometric indices from a sample of the general adult population in Nigeria

Males
 VC (R2 = 0.745, RSD = 0.41225)
  Predicted ˗1.163 + (-0.035)A + 0.039H
  LLN ˗2.148 + (-0.037)A + 0.034H
 FVC (R2 = 0.837, RSD = 0.29524)
  Predicted ˗ 0.848 + (-0.034)A + 0.035H
  LLN ˗1.487 + (-0.035)A + 0.031H
 FEV1 (R2 = 0.821, RSD = 0.28328)
  Predicted ˗0.834 + (-0.031)A + 0.031H
  LLN ˗1.448 + (-0.032)A + 0.028H
 FEV ratio (R2 = 0.08, RSD = 4.6897)
  Predicted 82.448 + (-0.120)A + 0.038H
  LLN 72.288 + (-0.206)A + (0.029)H
 FEV3 (R2 = 0.845, RSD = 0.27565)
  Predicted ˗0.613 + (-0.033)A + 0.033H
  LLN ˗1.210 + (-0.034)A + 0.029H
 FEV6 Same as for FVC
 MMEF (R2 = 0.450, RSD = 0.91509)
 Predicted 3.830 + (-0.051)A + 0.017H
  LLN 1.997 + (-0.054)A + 0.015H
 PEFR (R2 = 0.573, RSD = 1.11787)
  Predicted ˗4.199 + (-0.054)A + 0.091H
  LLN ˗6.621 + (-0.061)A + 0.078H
 MVV (R2 = 0.594, RSD = 20.3577)
  Predicted 34.221 + (-1.378)A + 0.915H
  LLN 20.883 + (-1.408)A + 0.671H
 FIVC (R2 = 0.707, RSD = 0.37060)
  Predicted ˗1.407 + (-0.027)A + 0.035H
  LLN ˗2.210 + (-0.029)A + 0.031H
 FIV1 (R2 = 0.661, RSD = 0.36884)
  Predicted ˗1.572 + (-0.023)A + 0.034H
  LLN ˗2.371 + (-0.025)A + 0.029H
 PIF (R2 = 0.458, RSD = 0.88486)
  Predicted ˗2.366 + (-0.029)A + 0.066H
  LLN ˗4.283 + (-0.035)A + 0.056H
Females
 VC (R2 = 0.688, RSD = 0.40299)
  Predicted ˗2.980 + (-0.029)A + 0.044H
  LLN ˗3.975 + (-0.032)A + 0.038H
 FVC (R2 = 0.876, RSD = 0.16623)
  Predicted ˗1.578 + (-0.022)A + 0.032H
  LLN ˗1.988 + (-0.023)A + 0.030H
 FEV1 (R2 = 0.761, RSD = 0.21655)
  Predicted ˗1.861 + (-0.018)A + 0.031H
  LLN ˗2.195 + (-0.019)A + 0.028H
 FEV ratio (R2 = 0.034, RSD = 5.6592)
  Predicted 60.815 + (-0.044A) + 0.177H
  LLN 48.554 + (-0.054A) + 0.152H
 FEV3 (R2 = 0.860, RSD = 0.17413)
  Predicted ˗2.374 + (-0.020)A + 0.036H
  LLN ˗2.804 + (-0.021)A + 0.033H
 FEV6 (R2 = 0.876, RSD = 0.16555)
  Predicted ˗1.521 + (-0.022)A + 0.032H
  LLN ˗1.930 + (-0.023)A + 0.029H
 MMEF (R2 = 0.552, RSD = 0.73682)
  Predicted ˗3.830 + (-0.041)A + 0.059H
  LLN ˗5.548 + (-0.045)A + 0.059H
 PEFR (R2 = 0.611, RSD = 0.77743)
  Predicted ˗4.986 + (-0.045)A + 0.082H
  LLN ˗5.903 + (-0.049)A + 0.070H
 MVV (R2 = 0.550, RSD = 10.2106)
  Predicted 3.752 + (-0.578)A + 0.752H
  LLN 5.102 + (-0.939)A + 0.579H
 FIVC (R2 = 0.676, RSD = 0.27872)
  Predicted ˗1.201 + (-0.020)A + 0.028H
  LLN ˗1.888 + (-0.022)A + 0.024H
 FIV1 (R2 = 0.575, RSD = 0.30378)
  Predicted ˗0.762 + (-0.018)A + 0.023H
  LLN ˗1.511 + (-0.020)A + 0.019H
 PIF (R2 = 0.564, RSD = 0.62244)
  Predicted ˗3.928 + (-0.030)A + 0.066H
  LLN ˗5.464 + (-0.034)A + 0.057H
  1. R 2 coefficient of determination, RSD residual standard deviation, LLN lower limit of normal, A age in years, H height in centimetres, VC vital capacity (Liters), FVC forced vital capacity (Liters), FEV 1 forced expiratory volume in one second (Liters), FEV ratio FEV1/FVC%, FEV 3 forced expiratory volume in three seconds (Liters), FEV 6 forced expiratory volume in six seconds (Liters), PEFR peak expiratory flow rate(Liters/sec), MMEF maximal mid expiratory flow (Liters/sec), MVV maximal voluntary ventilation (Liters/min), FIVC forced inspiratory vital capacity (Liters), FIV 1 forced inspiratory volume in one second (Liters), PIF peak inspiratory flow (Liters/sec)