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Table 1 Characteristics of participants by cohort studies

From: Tracking of accelerometry-measured physical activity during childhood: ICAD pooled analysis

  Avon Longitudinal Study of Parents and Children (ALSPAC) Children Living in Active Neighourhoods (CLAN) Healthy Eating and Play Study (HEAPS) Iowa Bone Development Study (IBDS) Personal and Environmental Associations with Children’s Health (PEACH)
Country United Kingdom Australia Australia United States United Kingdom
Source population Birth cohort recruited from a Bristol health district Students in Melbourne public schools Students in Melbourne public and catholic schools Birth cohort recruited from Iowa hospitals Students in Bristol public schools
Accelerometry data files, a follow-up/baseline, n (%) 4102/6085 (67%) 511/1162 (44%) 327/1390 (24%) 456/528 (86%) 889/1269 (70%)
Sample, b n 3324 444 259 415 579
Compliance rate, c % 81 87 79 91 65
Gender      
Boys, % 46.8 47.5 52.1 50.1 41.6
Girls, % 53.2 52.5 47.9 49.9 58.4
Data collection months     
Baseline All Jul-Dec Feb-Nov Sep-Nov Sep-Jul
Follow-up All Jul-Nov May-Nov Sep-Nov Oct-Jul
   Median (interquartile)  
Follow-up duration, years 2.1 (2.0, 2.3) 3.0 (2.9, 3.0) 3.0 (3.0, 3.1) 2.0 (2.0, 2.0) 1.1 (1.0, 1.1)
Ages, years      
Baseline 11.7 (11.6, 11.8) 10.9 (6.3, 11.6) 6.4 (5.8, 10.9) 11.0 (10.9, 11.2) 10.9 (10.6, 11.2)
Follow-up 13.8 (13.8, 13.9) 13.9 (9.2, 14.6) 9.6 (9.0, 13.9) 13.0 (12.9, 13.2) 12.0 (11.7, 12.3)
Height, m      
Baseline 1.50 (1.46, 1.55) 1.42 (1.20, 1.51) 1.24 (1.16, 1.44) 1.49 (1.43, 1.54) 1.45 (1.40, 1.50)
Follow-up 1.63 (1.58, 1.68) 1.60 (1.39, 1.68) 1.44 (1.34, 1.62) 1.62 (1.56, 1.66) 1.51 (1.46, 1.57)
Weight, kg      
Baseline 41.4 (36.2, 48.6) 35.5 (23.7, 43.8) 27.0 (21.7, 37.7) 41.8 (35.2, 51.0) 37.0 (33.0, 44.0)
Follow-up 52.6 (46.8, 60.2) 51.1 (35.3, 61.1) 41.0 (31.7, 53.6) 53.7 (45.4, 64.1) 42.8 (37.6, 50.8)
Accelerometer wear days     
Baseline 7 (6, 7) 6 (5, 6) 5 (4, 6) 5 (4, 5) 5 (4, 6)
Follow-up 6 (5, 7) 6 (5, 6) 5 (4, 6) 5 (4, 5) 5 (4, 6)
Accelerometer wear time, hours/day     
Baseline 13.3 (12.8, 13.8) 13.1 (12.4, 13.9) 12.7 (12.0, 13.5) 12.8 (12.5, 13.5) 13.0 (12.4, 13.6)
Follow-up 13.5 (12.8, 14.1) 13.6 (12.9, 14.2) 13.2 (12.4, 13.9) 13.1 (12.6, 13.8) 13.3 (12.6, 14.0)
MVPA, minutes/day     
Baseline 52.3 (37.1, 70.9) 61.2 (47.7, 78.2) 67.4 (48.8, 88.7) 45.6 (32.6, 63.8) 43.3 (30.9, 57.7)
Follow-up 48.5 (33.3, 68.8) 59.1 (43.1, 79.0) 49.0 (33.8, 68.7) 40.0 (25.2, 57.3) 45.5 (32.2, 62.1)
VPA, minutes/day     
Baseline 13.0 (7.6, 22.1) 17.2 (11.0, 26.0) 17.6 (10.8, 28.0) 12.4 (6.4, 22.6) 8.2 (4.5, 14.0)
Follow-up 14.0 (7.2, 24.4) 19.3 (11.4, 33.0) 11.3 (6.0, 19.2) 10.2 (5.0, 18.3) 8.0 (3.8, 14.2)
  1. MVPA, moderate- to vigorous-intensity physical activity; VPA, vigorous-intensity physical activity.
  2. aThe number of accelerometry data files at follow-up was obtained from the number of participants who had accelerometry data files at follow-up among those who had accelerometry data files at baseline in the ICAD dataset.
  3. bSample size was the number of participants who had age, gender, and valid accelerometry data (≥ 10 hours/day and ≥ 3 wear days) at both baseline and follow-up.
  4. cCompliance rate was calculated as sample size divided by the number of participants who had accelerometry data files at both baseline and follow-up.
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