Table 4—

Comparison of predicted values for subjects aged 70 yrs, age regression coefficients, and variation around regression from previous reference value studies

First author [ref. no.]		FEV₁						FEV₁/FVC%
First author [ref. no.]		Male			Female			Male			Female
	Subjects n	Pred^#	Age	RSD^¶	Pred^#	Age	RSD^¶	Pred^#	Age	RSD^¶	Pred^#	Age	RSD^¶
Present study	71	3.03	−0.044	0.55	2.10	−0.041	0.36	74.2	−0.30	5.8	76.6	−0.44	6.5
Enright 3	777	2.80	−0.027	0.51	2.13	−0.033	0.30	73.2	−0.29	6.9	75.4	−0.24	6.7
Crapo 2	251	3.14	−0.024	0.49	2.11	−0.026	0.33	77.8	−0.15	4.8	76.6	−0.25	5.3
Gulsvik 9	470	3.17			2.20			83.3	−0.09	4.3	80.7	−0.10	4.6
Quanjer 5		2.79	−0.029	0.51	1.97	−0.025	0.38	74.6	−0.18	7.2	75.8	−0.19	6.5
Hankinson 4	7429	2.87			2.17			73.6	−0.21		75.9	−0.21
Knudson 10	112	2.75	−0.029	0.52	2.16	−0.040	0.38	79.3	−0.11	6.3	78.8	−0.19	7.6

FEV₁: forced expiratory volume in one second
FVC: forced vital capacity.
^#: predicted (Pred) values for age 70 yrs, height 170 cm for males and 160 cm for females
^¶: residual standard deviation (RSD) from the linear regression model containing intercept, height, and age