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. Author manuscript; available in PMC: 2015 Jun 1.
Published in final edited form as: Bone. 2014 Mar 13;63:95–100. doi: 10.1016/j.bone.2014.03.004

Table 3.

Longitudinal mixed regression model analysis of BMC for boys (n = 156) at ages 13 and 15 as predicted MVPA and Vigorous PA at age 5.

Effect (A) Without BMC at Age 5
(B) With BMC at Age 5
β SE P Value β SE P Value
Spine BMC Intercept −126.024 8.929 < 0.001 −132.847 9.248 < 0.001
Age 4.613 0.437 < 0.001 4.877 0.459 < 0.001
Ht (cm) 0.572 0.062 < 0.001 0.540 0.065 < 0.001
Wt (kg) 0.035 0.038 0.355 0.021 0.038 0.590
Maturity (0,1) 2.632 0.979 0.008 2.554 1.011 0.013
MVPA at age 5 0.799 0.243 0.001 0.695 0.245 0.005
Spine BMC at age 5 …. …. …. 0.687 0.235 0.004
Concurrenta MVPA (min/day) 0.229 0.150 0.129 0.182 0.156 0.246
Spine BMC Intercept −122.811 8.835 < 0.001 −130.361 9.236 < 0.001
Age 4.751 0.440 < 0.001 5.004 0.462 < 0.001
Ht (cm) 0.570 0.063 < 0.001 0.539 0.066 < 0.001
Wt (kg) 0.031 0.038 0.419 0.017 0.038 0.655
Maturity (0,1) 2.464 0.977 0.013 2.355 1.014 0.021
Vigorous PA at age 5 1.338 0.529 0.012 1.079 0.539 0.047
Spine BMC at age 5 …. …. …. 0.702 0.241 0.004
Concurrenta Vigorous PA (min/day) 0.574 0.300 0.058 0.454 0.314 0.150
Hip BMC Intercept −78.328 6.136 < 0.001 −79.011 6.265 < 0.001
Age 1.450 0.286 < 0.001 1.793 0.305 < 0.001
Ht (cm) 0.458 0.044 < 0.001 0.401 0.045 < 0.001
Wt (kg) 0.098 0.026 < 0.001 0.070 0.026 0.009
Maturity (0,1) 1.149 0.680 0.093 1.563 0.726 0.033
MVPA at age 5 0.480 0.172 0.006 0.323 0.168 0.057
Hip BMC at age 5 …. …. …. 1.250 0.265 < 0.001
Concurrenta MVPA (min/day) 0.129 0.102 0.211 0.087 0.108 0.423
Hip BMC Intercept −76.442 6.050 < 0.001 −77.904 6.193 < 0.001
Age 1.532 0.288 < 0.001 1.881 0.306 < 0.001
Ht (cm) 0.459 0.044 < 0.001 0.398 0.046 < 0.001
Wt (kg) 0.096 0.026 < 0.001 0.069 0.027 0.011
Maturity (0,1) 1.029 0.678 0.131 1.459 0.728 0.047
Vigorous PA at age 5 0.676 0.376 0.074 0.319 0.369 0.388
Hip BMC at age 5 …. …. …. 1.325 0.268 < 0.001
Concurrenta Vigorous PA (min/day) 0.344 0.204 0.093 0.247 0.214 0.250

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.

a

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