Table 5

Results from mixed linear regression analyses of effect of leisure time physical activity on body composition in 47 extremely preterm (EP) born children and their 49 age-matched and gender-matched term-born (TB) controls born in year 1999–2000 in the Western Norway health region and examined in 2010–2011 as part of the Project Extreme Prematurity

Variables, unitsEP bornTBPhysical activityPhysical activity
EP compared with TB
P value
Mean95% CIMean95% CIDifference*95% CIP valueEffect †95% CIP valueEffect‡95% CI
Weight, z-score−0.34(-0.63, to 0.05)−0.13(−0.43 to 0.16)−0.20(−0.60 to 0.20)0.32−0.09(−0.28 to 0.11)0.39−0.03(−0.44 to 0.36)0.88
BMI, z-score−0.19(−0.47 to 0.09)−0.21(−0.49 to 0.07)−0.02(−0.39 to 0.43)0.92−0.10(−0.29 to 0.09)0.280.03(−0.36 to 0.42)0.89
FMI, kg/m24.2(3.5 to 4.9)4.4(3.7 to 5.0)−0.2(−1.1 to 0.8)0.70−0.9(-1.3, to 0.4)<0.0010.5(−0.5 to 1.4)0.32
Total body fat, %26.0(23.3 to 28.7)26.1(23.5 to 28.8)−0.16(−4.0 to 3.7)0.94−4.1(-6.0, to 2.1)<0.0012.3(−1.6 to 6,2)0.25
ALMI, kg/m25.5(5.3 to 5.7)5.8(5.6 to 5.9)−0.3(-0.5, to 0.1)0.020.1(−0.1 to 0.2)0.44−0.3(-0.6, to 0.1)0.012
LBMI, kg/m211.3(11.0 to 11.6)11.6(11.3 to 11.8)−0.3(−0.7 to 0.2)0.200.1(−0.1 to 0.4)0.27−0.6(-1.1, to 0.1)0.02
STR0.78(0.72 to 0.85)0.69(0.63 to 0.76)0.09(0.00 to 0.17)0.040.005(−0.04 to 0.05)0.83−0.09(−0.18 to 0.01)0.07
WHtR0.44(0.43 to 0.45)0.44(0.43 to 0.45)0.00(−0.01 to 0.03)0.79−0.01(−0.02 to 0.00)0.11−0.00(−0.02 to 0.02)0.71
Fat mass ratio1.11(1.05 to 1.17)1.25(1.19 to 1.30)−0.13(-0.21, to 0.06)0.0010.00(−0.04 to 0.05)0.840.04(−0.05 to 0.13)0.42
BMC, g1096(1016 to 1176)1256(1177 to 1335)−160(-252, to 67)0.00114(−41 to 69)0.63−126(-245, to 6)0.04
BMD, g/cm20.809(0.788 to 0.830)0.863(0.843 to 0.884)−0.054(-0.078, to 0.030)<0.0010.008(−0.007 to 0.022)0.28−0.034(-0.065, to 0.003)0.03
BMD, z-score−0.07(−0.28 to 0.14)0.43(0.22 to 0.64)−0.50(-0.78, to 0.22)<0.0010.09(−0.07 to 0.25)0.27−0.39(-0.71, to 0.07)0.02
BMD, spine z-score−0.06(−0.29 to 0.17)−0.13(-0.35, to 0.10)0.06(−0.26 to 0.39)0.700.03(−0.15 to 0.21)0.73−0.23(−0.59 to 0.13)0.20
BMDth left, z-score−0.07(−0.33 to 0.19)0.44(0.18 to 0.69)−0.51(-0.84, to 0.17)0.0040.21(0.02 to 0.40)0.03−0.53(-0.91 to 0.15)0.007
BMDth right, z-score−0.12(−0.37, 0.14)0.38(0.14, 0.63)−0.50(-0.83, -0.17)0.0040.24(0.05, 0.42)0.001−0.50(-0.87 to -0.13)0.009
  • *Unadjusted difference between EP born and TB.

  • †Estimated overall effect of physical activity.

  • ‡Estimated difference in effect of PA on EP born compared with TB (interaction term). Boldface denotes significant group differences.

  • ALMI, appendicular lean mass index;BMC, bone mineral content;BMD, bone mineral density;BMDth, total hip bone mineral density;LBMI, lean body mass index;PA, physical activity;STR, subscapular-triceps skinfold ratio; WHtR, waist-to-height ratio; Fat mass ratio, (arms+legs fat mass)/truncal fat mass.