Table 1 Study and participant characteristics

Country

UK

Denmark

Portugal

Australia

US

UK

UK

Australia

Number of waves

2 waves

2 waves

2 waves

2 waves

4 waves

2 waves

3 waves

3 waves

Average follow-up duration (years)

W1-W2

2.1 ± 0.3

6.0 ± 0.3

7.2 ± 0.2

3.1 ± 0.2

2.9 ± 0.5

1.1 ± 0.1

1.0 ± 0.04

3.0 ± 0.06

W1-W3

5.4 ± 0.5

4.1 ± 0.1

4.9 ± 0.2

W1-W4

7.4 ± 0.5

Data-collection period

W1

All months 2003–2005

All months 1997–1998

January – June 2000

February – December 2002–2003

September –November 1998–2000

January – November 2006–2008

February – July 2007

March–December 2001

W2

All months 2005–2007

All months 2003–2004

January – July 2007–2008

May – December

September –November 2000–2004

All, 2007–2009

March – July 2008

July – November 2004

W3

September –November 2003–2005

April–September 2011

May–November 2006

W4

September–December 2005–2007

Number of participants with baseline accelerometer data / valid baseline accelerometer data

W1

6085 / 5455

529 / 283

1218 / 631

1389 / 1040

437 / 329

1269 / 816

2009 / 1708

1162 / 1022

Number of participants included in analysis

W1

2992

122

33

226

306

386

663

428

W2

2992

122

33

226

227

386

565

361

W3

267

275

324

W4

213

Gender (% boys)

W1

46.6

41.0

36.4

51.8

46.4

39.9

43.4

46.3

Mean age and range (years)

W1

11.7 ± 0.2 (10.6–13.6)

9.6 ± 0.4 (8.6–10.5)

9.7 ± 0.3 (9.1–10.4)

8.1 ± 2.6 (5.0–12.6)

5.6 ± 0.5 (4.7–7.5)

10.9 ± 0.4 (10.1–11.8)

10.2 ± 0.3 (9.5–10.8)

9.5 ± 2.7 (5.5–15.0)

W2

13.8 ± 0.2 (12.6–14.8)

15.7 ± 0.4 (14.9–16.8)

16.9 ± 0.31 (16.3–17.5)

11.2 ± 2.6 (8.1–15.9)

8.6 ± 0.5 (7.6–10.7)

12.0 ± 0.4 (11.1–12.8)

10.8 ± 0.4 (10.0–12.0)^b

12.5 ± 2.7 (8.5–15.9)

W3

11.1 ± 0.3 (10.6–12.7)

14.3 ± 0.3 (13.7–14.9)

14.1 ± 2.6 (10.5–17.7)

W4

13.0 ± 0.3 (12.5–14.4)

BMI z-score

W1

0.31 ± 1.16

0.19 ± 0.98

0.44 ± 1.33

0.69 ± 0.98

0.37 ± 1.06

0.29 ± 1.17

0.37 ± 1.16

0.60 ± 1.04

W2

0.20 ± 1.09

0.08 ± 0.86

0.22 ± 0.99

0.62 ± 0.99

0.65 ± 1.31

0.30 ± 1.17

NA.

0.60 ± 1.07

W3

0.73 ± 1.31

0.25 ± 1.20

0.54 ± 1.04

W4

0.65 ± 1.28

Total sedentary time (minutes/day)

W1

370 ± 68

333 ± 101

366 ± 116

282 ± 73

246 ± 49

387 ± 64

371 ± 64

316 ± 79

W2

425 ± 76

492 ± 72

544 ± 78

388 ± 96

318 ± 57

414 ± 69

391 ± 65

381 ± 92

W3

356 ± 65

475 ± 73

446 ± 104

W4

413 ± 73

Prolonged sedentary time (minutes/day)

W1

158 ± 62

143 ± 103

183 ± 134

102 ± 45

81 ± 36

177 ± 61

172 ± 61

122 ± 57

W2

209 ± 78

272 ± 90

366 ± 97

176 ± 90

118 ± 49

196 ± 63

191 ± 64

172 ± 79

W3

148 ± 56

269 ± 81

237 ± 110

W4

203 ± 73

Day-to-day variation in total sedentary time (minutes/day)

W1

54 ± 19

53 ± 21

50 ± 24

48 ± 19

41 ± 19

55 ± 21

54 ± 21

51 ± 22

W2

60 ± 22

68 ± 27

74 ± 37

56 ± 21

47 ± 21

60 ± 22

55 ± 19

57 ± 22

W3

51 ± 22

64 ± 25

63 ± 27

W4

57 ± 25

Day-to-day variation in prolonged sedentary time (minutes/day)

W1

47 ± 19

45 ± 24

44 ± 23

40 ± 20

32 ± 17

48 ± 19

48 ± 20

43 ± 22

W2

55 ± 23

63 ± 28

84 ± 34

51 ± 23

38 ± 20

53 ± 21

53 ± 20

52 ± 24

W3

43 ± 20

63 ± 23

61 ± 30

W4

57 ± 23

MVPA^c (minutes/day)

(median with (interquartile range))

W1

30 (24)

23 (25)

19 (33)

38 (28)

25 (18)

21 (17)

25 (21)

35 (23)

W2

30 (26)

17 (20)

23 (22)

26 (23)

31 (24)

23 (20)

23 (21)

39 (30)

W3

26 (26)

20 (21)

29 (24)

W4

22 (24)

Accelerometer wear time (minutes/day)

W1

792 ± 52

776 ± 56

783 ± 72

755 ± 64

768 ± 43

769 ± 60

773 ± 57

782 ± 65

W2

792 ± 62

831 ± 56

820 ± 78

778 ± 66

786 ± 44

786 ± 70

773 ± 61

796 ± 65

W3

783 ± 43

796 ± 63

803 ± 66

W4

790 ± 57