Table 4.

Longitudinal mixed regression model analysis of BMC for girls (n = 170) at ages 13 and 15 as predicted by MVPA and Vigorous PA at age 5.

	Effect	(A) Without BMC at Age 5			(B) With BMC at Age 5
	Effect	β	SE	P Value	β	SE	P Value
Spine BMC	Intercept	−136.639	10.511	< 0.001	−131.011	9.930	< 0.001
	Age	2.547	0.200	< 0.001	3.257	0.212	< 0.001
	Ht (cm)	0.848	0.078	< 0.001	0.596	0.076	< 0.001
	Wt (kg)	0.211	0.038	< 0.001	0.161	0.036	< 0.001
	MVPA at age 5	0.037	0.030	0.211	0.037	0.026	0.151
	Spine BMC at age 5	….	….	….	1.931	0.241	< 0.001
	Concurrent^a MVPA (min/day)	−0.022	0.014	0.103	−0.025	0.015	0.098
Spine BMC	Intercept	−137.555	10.440	< 0.001	−132.751	9.887	< 0.001
	Age	2.577	0.202	< 0.001	3.306	0.214	< 0.001
	Ht (cm)	0.862	0.079	< 0.001	0.600	0.078	< 0.001
	Wt (kg)	0.222	0.039	< 0.001	0.163	0.037	< 0.001
	Vigorous PA at age 5	0.211	0.650	0.746	0.500	0.555	0.370
	Spine BMC at age 5	….	….	….	1.951	0.242	< 0.001
	Concurrent^a Vigorous PA (min/day)	−0.106	0.200	0.599	−0.137	0.217	0.527
Hip BMC	Intercept	−62.340	4.804	< 0.001	−60.055	4.460	<0.001
	Age	0.350	0.092	< 0.001	0.585	0.096	< 0.001
	Ht (cm)	0.457	0.035	< 0.001	0.381	0.033	< 0.001
	Wt (kg)	0.137	0.017	< 0.001	0.109	0.016	< 0.001
	MVPA at age 5	0.302	0.128	0.020	0.174	0.111	0.120
	Hip BMC at age 5	….	….	….	1.379	0.187	< 0.001
	Concurrent^a MVPA (min/day)	−0.010	0.049	0.846	−0.007	0.050	0.883
Hip BMC	Intercept	−61.036	4.670	< 0.001	−59.413	4.340	< 0.001
	Age	0.357	0.092	< 0.001	0.599	0.096	< 0.001
	Ht (cm)	0.459	0.035	< 0.001	0.379	0.033	< 0.001
	Wt (kg)	0.137	0.017	< 0.001	0.109	0.016	< 0.001
	Vigorous PA at age 5	0.361	0.280	0.199	0.302	0.237	0.120
	Hip BMC at age 5	….	….	….	1.416	0.185	< 0.001
	Concurrent^a Vigorous PA (min/day)	0.018	0.093	0.850	0.018	0.096	0.883

β, regression parameter estimate; BMC, bone mineral content; MVPA, moderate and vigorous-intensity physical activity; PA, physical activity

Box-Cox transformed MVPA and Vigorous PA minutes used for inferential analyses.

Concurrent = 13 and/or 15 yr for Panels (A) and (B)

Note: maturity offset not included since 98.8% were mature at age 13 and 100% were mature at age 15