Table 1.
Basic characteristics of study participants of the China Health and Nutrition Survey (1993 – 2011), stratified by study wave and age group (adult and child participants)
| Wave | 1993 | 1997 | 2000 | 2004 | 2006 | 2009 | 2011 |
|---|---|---|---|---|---|---|---|
| Adult participants | (n = 6416) | (n = 6644) | (n = 7357) | (n = 6826) | (n =6540) | (n = 6700) | (n = 6182) |
| Age, mean [SD] | 37.1 [11.4] | 38.1 [11.2] | 39.6 [11.0] | 42.0 [10.8] | 42.8 [10.7] | 43.2 [10.9] | 44.1 [10.7] |
| Sex (Female), n (%) | 3363 (52.4) | 3395 (51.1) | 3830 (52.1) | 3568 (52.3) | 3459 (52.9) | 3534 (52.8) | 3302 (53.4) |
| Education, n (%) | |||||||
| Primary school or less | 1498 (23.4) | 1287 (19.4) | 1049 (14.3) | 839 (12.3) | 976 (14.9) | 892 (13.3) | 719 (11.6) |
| Junior high school | 1359 (21.2) | 1475 (22.2) | 1602 (21.8) | 1504 (22.0) | 1120 (17.1) | 1150 (17.2) | 1006 (16.3) |
| High school | 2131 (33.2) | 2193 (33.0) | 2580 (35.1) | 2489 (36.5) | 2316 (35.4) | 2617 (39.1) | 2433 (39.4) |
| Attained further education | 1368 (21.3) | 1556 (23.4) | 1977 (26.9) | 1982 (29.0) | 2113 (32.3) | 2036 (30.4) | 2016 (32.6) |
| Missing | 60 (0.9) | 133 (2.0) | 149 (2.0) | 12 (0.2) | 15 (0.2) | 5 (0.1) | 8 (0.1) |
| Household Income, n (%) (1) | |||||||
| Low | 3686 (57.5) | 2901 (43.7) | 2569 (34.9) | 1902 (27.9) | 1625 (24.9) | 970 (14.5) | 714 (11.6) |
| Middle | 2157 (33.6) | 2793 (42.0) | 3016 (41.0) | 2347 (34.4) | 2102 (32.1) | 1837 (27.4) | 1270 (20.5) |
| High | 556 (8.7) | 906 (13.6) | 1657 (22.5) | 2510 (36.8) | 2707 (41.4) | 3813 (56.9) | 4103 (66.4) |
| Missing | 17 (0.3) | 44 (0.7) | 115 (1.6) | 67 (1.0) | 106 (1.6) | 80 (1.2) | 95 (1.5) |
| Urbanization index, mean [SD] (2) | 47.8 [16.3] | 52.8 [18.2] | 58.5 [18.3] | 62.4 [20.0] | 64.5 [20.1] | 67.0 [19.2] | 68.5 [18.6] |
| Waist-to-height ratio, mean [SD] (3) | 0.469 [0.054] | 0.479 [0.055] | 0.489 [0.058] | 0.498 [0.058] | 0.499 [0.058] | 0.506 [0.061] | 0.513 [0.062] |
| Child participants | (n=1195) | (n=2057) | (n=2091) | (n=1324) | (n=1025) | (n=912) | (n=819) |
| Age, mean [SD] | 13.6 [2.9] | 12.5 [2.7] | 12.9 [2.5] | 13.2 [2.8] | 12.8 [2.9] | 12.5 [2.6] | 12.4 [2.7] |
| Sex (Female), n (%) | 586 (49) | 964 (46.9) | 983 (47) | 627 (47.4) | 495 (48.3) | 405 (44.4) | 403 (49.2) |
| Education, n (%) | |||||||
| Primary school or less | 29 (2.4) | 43 (2.1) | 10 (0.5) | 12 (0.9) | 26 (2.5) | 20 (2.2) | 27 (3.3) |
| Junior high school | 201 (16.8) | 234 (11.4) | 218 (10.4) | 143 (10.8) | 120 (11.7) | 112 (12.3) | 118 (14.4) |
| High school | 589 (49.3) | 966 (47) | 991 (47.4) | 672 (50.8) | 455 (44.4) | 463 (50.8) | 382 (46.6) |
| Attained further education | 374 (31.3) | 807 (39.2) | 858 (41) | 497 (37.5) | 424 (41.4) | 317 (34.8) | 292 (35.7) |
| Missing | 2 (0.2) | 7 (0.3) | 14 (0.7) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Household income, n (%) (1) | |||||||
| Low | 766 (64.1) | 1078 (52.4) | 860 (41.1) | 458 (34.6) | 337 (32.9) | 197 (21.6) | 168 (20.5) |
| Middle | 347 (29) | 761 (37) | 865 (41.4) | 489 (36.9) | 350 (34.2) | 299 (32.8) | 221 (27) |
| High | 82 (6.9) | 200 (9.7) | 326 (15.6) | 356 (26.9) | 319 (31.1) | 402 (44.1) | 416 (50.8) |
| Missing | 0 (0.0) | 18 (0.9) | 40 (1.9) | 21 (1.6) | 19 (1.9) | 14 (1.5) | 14 (1.7) |
| Urbanization index, mean [SD] (2) | 46.5 [16.4] | 50.6 [17.6] | 55.8 [17.1] | 59.9 [19.7] | 62.4 [20.1] | 64.4 [19.1] | 66.6 [18.5] |
| Waist-to-height ratio, mean [SD] (3) | 0.426 [0.041] | 0.430 [0.041] | 0.428 [0.042] | 0.429 [0.046] | 0.426 [0.047] | 0.430 [0.050] | 0.436 [0.055] |
(1)
Household income was divided by square root of the number of household members and categorized into tertiles (low, middle and higher).
(2)
The urbanization index theoretically ranges from 0 to 120, with a higher value indicating more urbanized community environment.
(3)
Waist-to-height ratio was calculated as waist circumference divided by standing height.