Table 2.

Correlation coefficients between the values of CF or POS and LS-aBMD and central-vBMD and PS-vBMD

	LS-aBMD		Central-vBMD		PS-vBMD
	r	P	r	P	r	P
CF 0M	0.38	0.16	0.49	0.08	0.39	0.08
CF 12M	0.29	0.29	0.64	< 0.05	0.60	< 0.05
CF 24M	0.34	0.22	0.78	< 0.01	0.67	< 0.01
POS 0M	0.58	< 0.05	0.45	0.16	0.39	0.19
POS 12M	0.34	0.21	0.54	< 0.05	0.58	< 0.05
POS 24M	0.35	0.20	0.62	< 0.05	0.83	< 0.01

0M baseline, 12M 12 months, 24M 24 months, LS-aBMD lumbar spine areal bone mineral density, central-vBMD central volumetric bone mineral density, PS-vBMD pedicle screw volumetric bone mineral density of the left side, CF compression force, POS pullout strength, r correlation coefficient, P P value, n.s. not significant