. Author manuscript; available in PMC: 2008 Feb 1.

Published in final edited form as: Bone. 2006 Oct 27;40(2):529–537. doi: 10.1016/j.bone.2006.09.014

Table 4.

Slopes and heritability coefficients for markers of bone metabolism in men and women

	Men		Women

	Slope	H² (%)	Slope	H² (%)

PTH	1.31 ± 0.24	92^*	1.24 ± 0.32	85^*
25-OH vitamin D	0.64 ± 0.18	82^*	0.67 ± 0.19	82^*
1,25-(OH)2 vitamin D	0.66 ± 0.23	76^*	0.80 ± 0.16	90^*
BSAP	0.64 ± 0.28	68	0.39 ± 0.11	82^*
Osteocalcin	0.60 ± 0.21	77^*	0.65 ± 0.17	82^*
DPD	0.48 ± 0.11^**	88^*	1.03 ± 0.12	96^*
NTX	0.78 ± 0.11	94^*	0.75 ± 0.23	80^*
PYD	0.46 ± 0.34	49	1.06 ± 0.23	88^*
Helical peptide	0.77 ± 0.11	95^*	1.15 ± 0.52	78^*
Urinary calcium	0.96 ± 0.09	97^*	1.23 ± 0.25	89^*

Subjects were identical twins assigned at random to sedentary bed rest (CON) or bed rest combined with lower body negative pressure treadmill exercise (EX). Slope data are means ± SD for 8 subjects per group for all variables except osteocalcin, for which n = 6.

Heritability coefficients are statistically significant, P < 0.05.

^**

Slopes for men and women are different, P < 0.05.