Table 2. Associations between change in body composition from birth to 6-7 years and tibial size and volumetric BMD assessed at age 6-7 years assessed by pQCT, and whole body BMC assessed by DXA. Data shown are standardised beta coefficient (SD per SD) and 95% confidence interval, with and without mutual adjustment, and for change in height.

		Change in lean mass			Change in fat mass
	n	Univariate	Adjusted for ΔFM	Adjusted for ΔFM & height growth	Univariate	Adjusted for ΔLM	Adjusted for ΔLM & height growth
Tibia (pQCT)
4% CSA	192	0.63 (0.49, 0.76) c	0.57 (0.42, 0.73) c	0.29 (0.10, 0.49) b	0.35 (0.20, 0.50) c	0.09 (−0.10, 0.27)	0.00 (−0.15, 0.16)
38% CSA	157	0.63 (0.50, 0.76) c	0.53 (0.37, 0.69) c	0.26 (0.08. 0.44) b	0.41 (0.27, 0.55) c	0.18 (0.01, 0.36) a	0.07 (−0.08, 0.22)
Cortical CSA	157	0.57 (0.45, 0.70) c	0.48 (0.32, 0.63) c	0.23 (0.05, 0.40) a	0.39 (0.25, 0.52) c	0.18 (0.02, 0.34) a	0.07 (−0.07, 0.21)
SSI	154	0.70 (0.56, 0.84) c	0.62 (0.45, 0.79) c	0.36 (0.18, 0.55) c	0.38 (0.22, 0.53)c	0.13 (−0.06, 0.31)	−0.01 (−0.16, 0.14)
Trabecular vBMD	192	0.26 (0.13, 0.40) c	0.30 (0.16, 0.45) c	0.24 (0.05, 0.43) a	0.04 (−0.10, 0.17)	−0.10 (−0.25, 0.05)	−0.13 (−0.27, 0.02)
Cortical vBMD	157	0.02 (−0.14, 0.18)	0.08 (−0.10, 0.25)	0.17 (−0.04, 0.38)	−0.10 (−0.25, 0.06)	−0.13 (−0.30, 0.04)	−0.12 (−0.29, 0.06)
Whole body (DXA)
BMC	198	0,81 (0.72, 0.90) a	0.71 (0.58, 0.83) c	0.31 (0.18, 0.45) c	0.54 (0.42, 0.66) c	0.23 (0.08,0.39) b	0.12 (0.02, 0.23) a
Anthropometry
Height	198	0.76 (0.66, 0.86) c	0.68 (0.56, 0.82) c	0.06 (−0.02,0.15)	0.47 (0.34, 0.59) c	0.17 (0.01, 0.32) a	0.03 (−0.04, 0.09)

^ap<0.05;

^bp<0.01;

^cp<0.001;

CSA: Cross sectional area; vBMD: volumetric Bone Mineral Density; SSI: Strength-strain index; BMC: Bone mineral content; ΔFM: change in fat mass; ΔLM: change in lean mass