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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)