Table 1.
Sample characteristics
| Variables [theoretical range] | Full sample (N = 1299) |
Accelerometry based sub-sample of adolescents (N = 553) | ||
|---|---|---|---|---|
| Household/family characteristics | % | % | ||
| Adolescent’s gender (girls) | 57.04 | 54.25 | ||
| Parent’s gender (female) | 76.44 | 76.49 | ||
| Mean (SD) | Median (IQR) | Mean (SD) | Median (IQR) | |
| Adolescent’s age (years) | 14.70 (1.57) | 14.62 (2.57) | 14.65 (1.56) | 14.58 (2.37) |
| Parent’s age (years) | 44.95 (6.45) | 45.00 (9.00) | 45.29 (6.13) | 45.00 (8.00) |
| Length of residence at current address (years) | 9.68 (6.62) | 10.00 (10.00) | 9.47 (6.74) | 9.00 (10.08) |
| Number of children in the household | 1.66 (0.75) | 2.00 (1.00) | 1.72 (0.75) | 2.00 (1.00) |
| PA equipment at home [0–10] | 4.98 (2.41) | 5.00 (4.00) | 4.96 (2.36) | 5.00 (3.00) |
| Social support for PA from household adults [0–4] | 1.46 (0.94) | 1.33 (1.33) | 1.52 (0.95) | 1.33 (1.33) |
| Parental rules about activity [0–14] | 9.24 (3.61) | 10.00 (5.00) | 9.51 (3.56) | 10.00 (5.00) |
| PA-related reasons for living in the neighbourhood (neighbourhood self-selection) [1–5] | 3.38 (0.74) | 3.43 (1.00) | 3.43 (0.74) | 3.43 (1.00) |
| Parental transport-related PA (min/week) | 166.61 (284.60) | 60.00 (210.00) | 165.12 (289.13) | 70.00 (210.00) |
| Parental leisure-time PA (min/week) | 122.65 (279.07) | 0.00 (120.00) | 128.67 (278.74) | 0.00 (150.00) |
| Proximity to school [1–5] | 2.19 (1.28) | 2.00 (2.00) | 2.17 (1.30) | 2.00 (2.00) |
| Number of motorised vehicles in the household | % | n | % | n |
| 0 | 69 | 898 | 68 | 377 |
| 1 | 23 | 298 | 23 | 128 |
| 2 or more | 8 | 103 | 9 | 48 |
| Monthly household income (HKD) | ||||
| < 15,000 | 29 | 380 | 27 | 152 |
| 15,000 – 29,999 | 30 | 390 | 30 | 165 |
| 30,000 – 59,999 | 19 | 248 | 21 | 116 |
| ≥ 60,000 | 22 | 281 | 22 | 120 |
| Household highest education level | ||||
| Lower secondary or below | 20 | 265 | 21 | 117 |
| Higher secondary | 34 | 438 | 32 | 179 |
| Associate Degree/Higher diploma | 12 | 149 | 11 | 63 |
| Bachelor or above | 34 | 447 | 35 | 194 |
| Marital status (Married or in de facto relationship) | 90 | 1163 | 90 | 498 |
| Type of household (Apartment/unit /flat) | 89 | 1160 | 87 | 483 |
| Area level socio-economic status (High) | 47 | 604 | 47 | 259 |
| Ethnicity/race (Chinese) | 90 | 1163 | 88 | 486 |
| School characteristics | Mean (SD) | Median (IQR) | Mean (SD) | Median (IQR) |
| PA equipment at school [0–6] | 4.53 (1.11) | 5.00 (1.00) | 4.58 (1.08) | 5.00 (1.00) |
| PA-friendly policy supporting after school PA [0–4] | 2.53 (0.84) | 2.50 (1.00) | 2.55 (0.86) | 2.50 (1.00) |
| Social support for PA from peers [0–4] | 1.15 (1.04) | 1.00 (2.00) | 1.26 (1.10) | 1.00 (2.00) |
| % | n | % | n | |
| School type (Public) | 96 | 1242 | 95 | 525 |
| Adolescent’s characteristics | Mean (SD) | Median (IQR) | Mean (SD) | Median (IQR) |
| Enjoyment of PA [1–5] | 3.73 (1.03) | 4.00 (2.00) | 3.85 (1.03) | 4.00 (2.00) |
| Attitude towards PA [1–5] | 3.17 (0.41) | 3.20 (0.60) | 3.20 (0.41) | 3.20 (0.60) |
| Athletic ability [1–5] | 2.84 (1.06) | 3.00 (2.00) | 2.92 (1.03) | 3.00 (2.00) |
| Adolescent’s self-reported PA | ||||
| Total weekly minutes of PA at school | ||||
| Time 1 | 155.8 (55.99) | 150.0 (54.00) | 161.8 (58.26) | 155.0 (56.00) |
| Time 2 | 163.8 (53.64) | 155.0 (50.00) | 168.2 (57.09) | 155.0 (60.00) |
| Participation in after school sports teams (#) [0–4] | ||||
| Time 1 | 1.09 (1.17) | 1.00 (2.00) | 1.15 (1.21) | 1.00 (2.00) |
| Time 2 | 1.02 (1.14) | 1.00 (2.00) | 1.08 (1.19) | 1.00 (2.00) |
| Accelerometry data | ||||
| Average MVPA (minutes per day) | ||||
| At school | 16.04 (9.48) | 13.88 (9.78) | ||
| After school | 9.59 (6.49) | 8.13 (8.33) | ||
| Time spent in MVPA as % of wear time | ||||
| At school | 3.70 (2.18) | 3.19 (2.24) | ||
| After school | 7.53 (4.94) | 6.64 (6.11) | ||
| Wear time as % of all time | ||||
| At school | 95.62 (6.40) | 99.04 (6.90) | ||
| After school | 94.04 (8.85) | 99.00 (9.80) | ||
| Duration of monitoring period | ||||
| Hours of school time per day | 7.58 (0.48) | 7.50 (0.83) | ||
| Hours of after school time pre day | 2.23 (0.30) | 2.33 (0.50) | ||
| Valid days at school | 4.93 (1.29) | 5.00 (1.00) | ||
SD = standard deviation; IQR = interquartile range; PA = physical activity; HKD = Hong Kong dollars; # = number
Time 1, Time 2 – data were collected at two time-points six months apart