Table 1.
Demographic characteristics among 6–9-year-old children, Beijing, China (N = 1914).
| Characteristics | Wave 1 (n = 1,914) | Wave 2 (n = 1,746) | Wave 3 (n = 1,651) | Wave 4 (n = 1,657) |
|---|---|---|---|---|
| Age (year)a | 6.6 ± 0.3 | 7.6 ± 0.3 | 7.6 ± 0.3 | 7.6 ± 0.3 |
| Sex, boysb | 956 (50.0) | 875 (50.1) | 820 (49.7) | 826 (49.8) |
| Height z-scorea | 0.67 ± 0.96 | 0.79 ± 0.97 | 0.77 ± 0.97 | 0.77 ± 0.97 |
| Weight z-scorea | 0.70 ± 1.41 | 0.99 ± 1.48 | 0.98 ± 1.48 | 0.98 ± 1.46 |
| Body mass index (BMI) z-scorea | 0.40 ± 1.54 | 0.70 ± 1.59 | 0.69 ± 1.59 | 0.70 ± 1.57 |
| Systolic blood pressure (SBP in mmHg)a | 101 ± 8 | 101 ± 8 | 101 ± 9 | 101 ± 8 |
| Diastolic blood pressure (DBP in mmHg)a | 56 ± 6 | 56 ± 6 | 56 ± 6 | 56 ± 6 |
| Short sleep (<10 h/d)b | 1,441 (75.3) | 1,327 (76.0) | 1,246 (75.5) | 1,249 (75.4) |
| Long screen time (≥2 h/d)b | 95 (5.0) | 86 (4.9) | 79 (4.8) | 80 (4.8) |
| Insufficient fruit/vegetable intake (FVI <4 /d)b | 931 (48.6) | 864 (49.5) | 813 (49.2) | 818 (49.4) |
| Insufficient physical activity (PA weekly average <1 h/d)b | 1,451 (75.8) | 1,323 (75.8) | 1,259 (76.3) | 1,267 (76.5) |
| Insufficient PA (weekly patterns <1 h/d)b | 1,649 (86.2) | 784 (44.9) | 1,493 (90.4) | 1,495 (90.2) |
| Dehydration status (specific gravity ≥1.02)b | 670 (35.0) | 1,085 (62.1) | 1,055 (63.9) | 1,049 (63.3) |
| Renal tubular damage (β2-MG >0.2 mg/L)b | 168 (8.8) | 277 (15.9) | 425 (25.7) | 481 (29.0) |
| Renal glomerular damage (MA ≥20 mg/L)b | 107 (5.6) | 96 (5.5) | 72 (4.4) | 68 (4.1) |
β2-MG, β2-microglobulin; MA, microalbumin;
a
Mean and standard deviation;
b
n (%).