Table 1.
Characteristics sample for different cohorts.
| Variables | 1980–1989 cohort | 1990–1999 cohort | 2000–2009 cohort | |||
|---|---|---|---|---|---|---|
| N | 9764 | 7119 | 5468 | |||
| HAZ M (SD) | − 0.61 | (3.2) | − 0.23 | (2.9) | 0.43 | (4.3) |
| BAZ M (SD) | − 0.12 | (2.9) | 0.21 | (3.5) | 0.45 | (4.7) |
| Educational level [N (%)] | ||||||
| Low | 4815 | (50.54) | 2457 | (38.13) | 1023 | (21.74) |
| High | 4713 | (49.46) | 3987 | (61.87) | 3682 | (78.26) |
| Household income per capita* | ||||||
| Median | 1254.20 | 3360 | 5100 | |||
| Range (P25–P75) | 180–5600 | 264–17,600 | 227–31,666 | |||
| Sex [N (%)] | ||||||
| Boy | 5271 | (53.98) | 3760 | (52.82) | 2975 | (54.51) |
| Girl | 4493 | (46.02) | 3359 | (47.18) | 2493 | (45.59) |
| Urban–rural area [N (%)] | ||||||
| Live in rural | 7062 | (72.33) | 5201 | (73.06) | 3990 | (72.97) |
| Live in urban | 2702 | (27.67) | 1918 | (26.94) | 1478 | (27.03) |
| Nationality [N (%)] | ||||||
| Ethnic minority | 1328 | (13.74) | 1094 | (15.41) | 815 | (14.97) |
| Han nationality | 8337 | (86.26) | 6003 | (84.57) | 4631 | (85.03) |
| Regional [N (%)] | ||||||
| Central-western | 6535 | (66.93) | 4512 | (63.38) | 3640 | (66.57) |
| Eastern | 3229 | (33.07) | 2607 | (36.62) | 1828 | (33.43) |
| Urbanization index | ||||||
| Median | 45.00 | 52.30 | 60.32 | |||
| Range (P25–P75) | 18.01–83.83 | 25.35–98.89 | 30.42–98.55 | |||
| Environment sanitation score M (SD) | 1.1 | (1.7) | 1.8 | (1.3) | 2.4 | (1.1) |
| No sister or brother [N (%)] | 5041 | (51.63) | 4862 | (68.30) | 5118 | (93.60) |
| Have sister or brother [N (%)] | 4723 | (48.37) | 2257 | (31.70) | 350 | (6.40) |
| Carbohydrate intake percentage M (SD) | 66.45 | (0.34) | 60.45 | (0.37) | 58.42 | (0.37) |
| Fat intake percentage M (SD) | 22.03 | (0.67) | 27.73 | (0.68) | 29.18 | (0.65) |
| Protein intake percentage M (SD) | 12.06 | (0.34) | 12.16 | (0.38) | 12.27 | (0.39) |
| Mother’s BMI (kg/m2) M (SD) | 22.21 | (2.76) | 22.77 | (3.51) | 22.84 | (3.07) |
| Father’s BMI (kg/m2) M (SD) | 22 | (2.55) | 22.77 | (2.88) | 23.11 | (3.12) |
| Mother’s height (m) M (SD) | 1.57 | (0.07) | 1.59 | (0.06) | 1.60 | (0.05) |
| Father’s height (m) M (SD) | 1.70 | (0.05) | 1.71 | (0.04) | 1.73 | (0.06) |
| Age (years) M (SD) | 11.59 | (3.38) | 11.61 | (3.49) | 10.99 | (3.32) |
Data are mean (SD) or n (%). N means measurements, M means mean, SD means standard deviation. HAZ and BAZ were height-for-age and BMI-for-age z-scores using sex- and age-specific WHO 2007 growth reference. *In Chinese currency (Yuan).