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Table 2 Mean anthropometric and body composition measures at 18y by adolescent movement behavior trajectories, Bt20+

From: Adolescent physical activity, sedentary behavior and sleep in relation to body composition at age 18 years in urban South Africa, Birth-to-Twenty+ Cohort

N BMI (kg/m2) Waist circumference (cm) Fat Mass Indexa (kg/m2) Lean Massb Indexc (kg/m2) Body fat (%) BMI (kg/m2) Waist circumference (cm) Fat Mass Index (kg/m2) Lean Mass Index (kg/m2) Body fat (%)
Males Females
638 638 449 449 449 699 699 509 509 509
Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD)
Informal activity
 Decreasing over time 20.4 (3.1) 72.1 (7.3) 2.5 (1.6) 15.7 (1.5) 13.4 (5.6) 23.1 (4.6) 75.4 (11.0) 7.2 (3.0) 13.1 (1.6) 33.5 (7.0)
 Increasing over time 19.4 (2.1) 69.9 (5.1) 1.9 (0.7) 14.7 (1.0) 11.1 (3.4) 23.9 (4.3) 80.1 (31.1) 8.4 (2.8) 13.8 (1.5) 35.8 (6.5)
  P-value 0.04 0.05 0.04 0.21 0.03 0.3 0.03 0.08 0.03 0.12
Organized sports participation
 Males
  Consistently low 30.4 (3.2) 72.1 (7.5) 2.5 (1.6) 15.0 (1.5) 13.4 (5.6)      
  Decreasing from adequate to low 19.8 (2.3) 71.5 (6.4) 2.3 (1.7) 14.7 (1.1) 12.6 (6.1)      
  Increasing from low to adequate 20.1 (1.9) 71.2 (5.0) 2.2 (0.9) 15.3 (1.4) 12.1 (4.0)      
   P-value 0.4 0.6 0.3 0.3 0.3      
 Females
  None       23.3 (4.7) 76.0 (13.2) 7.4 (3.01) 13.1 (1.7) 33.9 (6.9)
  Consistently some       22.3 (3.4) 72.8 (9.1) 6.5 (2.7) 13.1 (1.2) 31.1 (7.5)
   P-value       0.1 0.04 0.04 0.9 0.005
Walking to and from school
 Consistently 150 min/week 20.4 (3.1) 72.2 (7.4) 2.6 (1.6) 15.1(1.5) 13.4 (5.7) 23.2 (4.8) 75.8 (13.6) 7.4 (3.2) 13.1 (1.7) 33.7 (7.3)
 Consistently 300 min/week 19.9 (2.6) 71.0 (6.1) 2.2 (1.0) 14.9 (1.5) 12.1 (4.1) 23.0 (3.7) 75.2 (10.6) 7.1 (2.5) 13.2 (1.4) 33.2 (6.2)
  P-value 0.2 0.1 0.07 0.3 0.07 0.7 0.6 0.5 0.4 0.4
Overall physical activity d
 Decreasing activity over time and do not walk to school 20.9 (3.6) 72.3 (7.4) 3.0 (2.2) 15.1 (1.4) 14.9 (7.4) 23.6 (5.2) 75.6 (11.7) 7.7 (3.3) 13.1 (1.7) 34.7 (7.2)
 Decreasing activity over time but consistently walk to school 20.4 (3.1) 72.3 (7.3) 2.5 (1.3) 15.0 (1.6) 13.2 (4.9) 23.0 (4.3) 75.7 (11.0) 7.2 (3.0) 13.1 (1.6) 33.4 (6.8)
 Consistently more active and consistently walk to school 19.3 (2.0) 70.1 (6.0) 2.1 (1.1) 15.1 (1.2) 11.7 (4.3) 22.8 (3.9) 75.5 (20.0) 6.8 (2.7) 13.2 (1.4) 32.1 (7.1)
  P-value 0.001 0.03 0.0002 0.7 0.0001 0.2 0.9 0.1 0.8 0.03
Sedentary behavior
 Males
  Consistently low 20.1 (2.6) 71.5 (6.5) 2.5 (1.5) 15.0 (1.5) 13.2 (5.5)      
  Consistently high 20.7 (4.4) 72.6 (9.2) 2.1 (0.9) 14.7 (1.4) 12.0 (4.4)      
  Increasing from low to high 21.2 (3.8) 74.6 (8.8) 2.8 (1.8) 15.3 (1.4) 14.1 (6.3)      
   P-value 0.004 0.001 0.2 0.3 0.3      
 Females
  Initially low but increasing       23.1 (4.5) 75.2 (10.9) 7.3 (3.0) 13.1 (1.6) 33.6 (6.9)
  Consistently high       24.3 (5.0) 81.3 (26.7) 7.8 (3.6) 13.7 (1.7) 33.9 (8.4)
   P-value       0.05 0.0008 0.4 0.04 0.8
Schoolnight sleep
  ≤ 8 h/night 20.9 (3.7) 73.3 (8.5) 2.7 (1.7) 15.1 (1.6) 13.9 (5.9) 23.3 (4.6) 75.7 (14.0) 7.4 (2.9) 13.2 (1.6) 33.8 (6.9)
  ≥ 9 h/night 20.0 (2.5) 71.2 (6.2) 2.4 (1.4) 15.0 (1.4) 12.9 (5.3) 22.8 (4.5) 75.4 (10.6) 7.1 (3.2) 13.0 (1.7) 33.1 (7.2)
  P-value 0.0001 0.0007 0.06 0.3 0.06 0.1 0.8 0.3 0.2 0.3
  1. a Fat mass index, calculated by dividing fat mass (in kg) by height (in meters) squared
  2. b Lean mass does not include bone mineral content
  3. c Lean mass index, calculated by dividing lean mass (in kg) by height (in meters) squared
  4. d Multi-trajectory groups made up of informal activity, organized sports and walking to and from school trajectories, representing overall physical activity pattern
  5. P-values represent comparisons between groups for males and females, using ANOVA