Table 3.

Age-related differences in radius length and in selected cortical bone properties from the µCT, biochemical, and biomechanical analyses of the radius mid-shaft (Mean ± SD).

Property	Unit	n=12 6 months	n=12 12 months	n=12 24 months	p-value
					6 vs. 12	6 vs. 24	12 vs. 24
Lengtha	mm	27.4 ± 1.0	28.7 ± 0.5	28.8 ± 1.0	0.0011	0.0009	NS
Ct.Thb	mm	0.52 ± 0.02	0.51 ± 0.02	0.47 ± 0.05	NS	0.0008	0.0168
Ct.Ar	mm2	1.71 ± 0.07	1.88 ± 0.08	1.96 ± 0.06	<0.0001	<0.0001	NS
Tt.Ar	mm2	1.88 ± 0.08	2.09 ± 0.09	2.25 ± 0.06	<0.0001	<0.0001	<0.0001
Imin	mm4	0.25 ± 0.04	0.32 ± 0.03	0.37 ± 0.04	0.0001	<0.0001	NS
Ct.Po	%	3.7 ± 0.2	3.4 ± 0.6	4.8 ± 1.9	NS	NS	0.0231
Ct.TMD	mgHA/cm3	1169 ± 29	1205 ± 14	1220 ± 24	0.0014	<0.0001	NS
Collagen contentc	µmol/g	2.40 ± 0.25	2.27 ± 0.19	2.36 ± 0.22	ANOVA p=0.3667
DPD per col	mol/mol	0.51 ± 0.08	0.50 ± 0.11	0.59 ± 0.08	NS	NS	0.0451
Stiffnessd	N/mm	64.6 ± 6.05	94.5 ± 7.97	109.0 ± 8.57	<0.0001	<0.0001	<0.0001
Modulus	GPa	11.8 ± 0.88	14.0 ± 0.92	14.5 ± 1.09	<0.0001	<0.0001	NS
Peak force	N	25.3 ± 1.78	33.7 ± 2.78	36.2 ± 2.49	<0.0001	<0.0001	0.0128
Yield force	N	21.7 ± 1.66	29.7 ± 2.56	32.8 ± 2.31	<0.0001	<0.0001	0.0015
PYD	mm−1	0.032 ± 0.007	0.024 ± 0.005	0.018 ± 0.004	0.0028	<0.0001	0.0049
Wf	N mm	17.4 ± 2.54	19.1 ± 3.32	16.6 ± 2.61	ANOVA p=0.1064
Toughness	MJ/m3	2.16 ± 0.39	2.19 ± 0.37	1.83 ± 0.28	NS	0.0290
					0.0290

^aCaliper measurement of radius length;

^bµCT-derived properties;

^cCharacteristics from HPLC in which DPD is deoxypyridinoline, a mature enzymatic crosslink, normalized to collagen content (col); and

^dBiomechanical properties as determined from three-point bending tests.