Characteristics of participants
| Characteristic | Males | Females | ||
|---|---|---|---|---|
| n | Mean (SD) | n | Mean (SD) | |
| Age in years at physical activity monitoring | 2128 | 11.7 (0.23) | 2627 | 11.7 (0.23) |
| Birthweight (g) | 1996 | 3457.1 (579.6) | 2446 | 3375.2 (490.5) |
| Gestation (weeks) | 2020 | 39.4 (2.0) | 2484 | 39.5 (1.6) |
| Age of mother in years at delivery | 2020 | 29.2 (4.6) | 2484 | 28.9 (4.5) |
| BMI Z score at 11 | 2117 | 0.34 (1.17) | 2609 | 0.27 (1.17) |
| BMI Z score at 13 | 1093 | 0.27 (1.18) | 1392 | 0.18 (1.16) |
| BMI Z score at 16 | 1531 | 0.27 (1.07) | 1918 | 0.36 (1.06) |
| Number of valid days of accelerometry | 2128 | 5.9 (1.2) | 2627 | 5.9 (1.2) |
| Accelerometer wear time (min) | 2128 | 4639 (1040) | 2627 | 4557 (1006) |
| Counts-per-minute (cpm) | 2128 | 662 (186) | 2627 | 553 (153) |
| Average daily minutes of MVPA | 2128 | 29 (17) | 2627 | 18 (12) |
| Percentage of time spent in MVPA | 2128 | 8 (4) | 2627 | 5 (3) |
| n | Percentage | n | Percentage | |
| Ethnicity | ||||
| White | 1846 | 95.6 | 2281 | 96.4 |
| Non-white | 84 | 4.4 | 85 | 3.6 |
| BMI at 11 years | ||||
| Normal | 1512 | 71.4 | 1917 | 73.5 |
| Overweight | 288 | 13.6 | 339 | 13.0 |
| Obese | 317 | 15.0 | 353 | 13.5 |
| BMI at 13 years | ||||
| Normal | 810 | 74.1 | 1061 | 76.0 |
| Overweight | 143 | 13.1 | 192 | 13.8 |
| Obese | 140 | 12.8 | 139 | 10.0 |
| BMI at 16 years | ||||
| Normal | 1179 | 77.0 | 1444 | 75.5 |
| Overweight | 184 | 12.0 | 245 | 12.8 |
| Obese | 168 | 11.0 | 229 | 11.9 |
| Mother's oily fish intake | ||||
| Never/rarely | 714 | 37.2 | 900 | 38.3 |
| Once in 2 weeks | 674 | 35.2 | 806 | 34.3 |
| 1–3 times a week | 508 | 26.5 | 615 | 26.1 |
| 4–7 times a week | 20 | 1.0 | 30 | 1.3 |
| More than once a day | 1 | 0.1 | 1 | 0.0 |
| Mother smoked during pregnancy | ||||
| Yes | 308 | 15.5 | 411 | 16.8 |
| No | 1681 | 84.5 | 2029 | 83.2 |
| Mothers education | ||||
| CSE | 244 | 12.4 | 310 | 12.9 |
| Vocational | 171 | 8.7 | 186 | 7.8 |
| O level | 695 | 35.4 | 874 | 36.4 |
| A level | 536 | 27.3 | 632 | 26.3 |
| Degree | 317 | 16.1 | 397 | 16.5 |
| Occupational social class | ||||
| I (Professional) | 134 | 7.8 | 142 | 6.8 |
| II | 600 | 35.1 | 710 | 34.2 |
| III (Non-manual) | 734 | 42.9 | 894 | 43.0 |
| III (Manual) | 103 | 6.0 | 121 | 5.8 |
| IV | 122 | 7.1 | 180 | 8.7 |
| V (Unskilled) | 15 | 0.1 | 30 | 1.4 |
| Armed forces | 1 | 0.1 | 0 | 0 |
BMI body mass index; MVPA, moderate-vigorous intensity physical activity.