Table 1.
The Characteristics of the Study Participants
| Characteristics | All Mean (SD) | Boys Mean (SD) (n = 6244) | Girls Mean (SD) (n = 5715) | P Value |
|---|---|---|---|---|
| Age, y | 7.55 (1.05) | 7.56 (1.02) | 7.536 (1.07) | 0.144 |
| BMI, kg/m2 | 16.17 (3.07) | 16.45 (3.25) | 15.86 (2.82) | <0.001 |
| Height, cm | 124.88 (8.43) | 125.37 (8.14) | 124.34 (8.70) | <0.001 |
| Weight, kg | 25.49 (6.73) | 26.14 (6.98) | 24.78 (6.36) | <0.001 |
| Mean arterial blood pressure, mm Hg | 88.99 (14.93) | 89.16 (14.12) | 88.80 (15.77) | 0.192 |
| Axial length, mm | 23.13 (0.93) | 23.40 (0.90) | 22.84 (0.87) | <0.001 |
| Family income per mo, N (%) | ||||
| ≤ HK $20,000* | 3177 (26.57) | 1646 (26.36) | 1530 (26.77) | 0.366 |
| > HK $20,000* | 8782 (73.43) | 4598 (73.64) | 4185 (73.23) | |
| Physical activity, h/wk | 18.74 (3.22) | 18.67 (3.22) | 18.81 (3.21) | 0.019 |
| Physical inactivity, h/wk | 38.82 (4.27) | 38.84 (4.24) | 38.80 (4.29) | 0.661 |
| Ratio | 0.487 (0.091) | 0.485 (0.091) | 0.489 (0.092) | 0.009 |
| CRAE, µm | 151.6 (11.5) | 150.9 (11.3) | 152.4 (11.6) | <0.001 |
| CRVE, µm | 215.7 (16.3) | 214.9 (16.1) | 216.6 (16.5) | <0.001 |
*
Equivalent to US $2551.10.