. 2017 Oct 15;196(8):993–1003. doi: 10.1164/rccm.201610-1987OC

Table 3.

Model Parameters and R² Values for Each Spirometry Parameter and Sex

	Model	R² Women	R² Men
FEV₁, L	$β_{0 i} \times I (Ethnic = i) + β_{1} (Age - 45) + β_{2} {(Age - 45)}^{2} + β_{3} (Height - 160)$	0.58	0.54
FVC, L	$β_{0 i} \times I (Ethnic = i) + β_{1} (Age - 45) + β_{2} {(Age - 45)}^{2} + β_{3} (Height - 160)$	0.50	0.48
FEV₁/FVC, %	$β_{0 i} \times I (Ethnic = i) + β_{1} (Age - 45) + β_{2} {(Age - 45)}^{2} + β_{3} (Height - 160)$	0.31	0.20

Note: In all models, age was centered at 45 years, and height was centered at 160 cm.