Table 1. Associated sociodemographic factors of myopia in children.
| Variables | Total, n (%) | Myopia, n (%) | No myopia, n (%) | P-valuea |
|---|---|---|---|---|
| Total | 3055 (100) | 1447 (47.3) | 1608 (52.6) | — |
| Refractive error (D)b | −1.9 (±2.2) | −2.7 (±1.6) | 1.0 (1.5) | <0.001 |
| Myopia categories | — | — | — | |
| No myopia | 1608 (52.6) | |||
| Low myopia | 938 (30.7) | |||
| Moderate myopia | 453 (14.8) | |||
| High myopia | 56 (1.8) | |||
| Age (years)b | 13.6 (±1.6) | 15.4 (±1.3) | 12.6 (±1.2) | <0.001 |
| Gender | ||||
| Boy | 1579 (51.7) | 713 (45.1) | 866 (54.8) | 0.011 |
| Girl | 1476 (48.3) | 734 (49.7) | 742 (50.3) | |
| Grade | ||||
| 1 | 324 (10.6) | 7 (0.2) | 317 (97.8) | <0.001 |
| 2 | 308 (10.1) | 41 (13.3) | 267 (86.7) | |
| 3 | 340 (11.1) | 132 (38.8) | 208 (61.2) | |
| 4 | 284 (9.3) | 135 (47.5) | 149 (52.5) | |
| 5 | 277 (9.1) | 170 (61.3) | 107 (38.6) | |
| 6 | 442 (14.5) | 249 (56.3) | 193 (43.7) | |
| 7 | 366 (12.0) | 241 (65.8) | 125 (34.2) | |
| 8 | 398 (13.0) | 256 (64.3) | 142 (35.7) | |
| 9 | 316 (10.3) | 216 (68.4) | 100 (31.6) | |
| Ethnicity | ||||
| Han | 2696 (88.3) | 1319 (48.9) | 1377 (51.1) | 0.016 |
| Other ethnic groups | 359 (11.7) | 128 (35.6) | 231 (64.3) | |
| Family economic status | ||||
| Above average | 875 (28.6) | 411 (46.9) | 464 (53.0) | 0.081 |
| Average | 1871 (61.2) | 911 (48.7) | 960 (51.3) | |
| Below average | 263 (8.6) | 109 (41.4) | 154 (58.6) | |
| Missing data | 46 (1.5) | — | — | |
| Academic achievement | ||||
| Above average | 1123 (36.8) | 537 (47.8) | 586 (52.2) | 0.254 |
| Average | 1039 (34.0) | 476 (45.8) | 563 (54.2) | |
| Below average | 834 (27.3) | 414 (49.6) | 429 (51.4) | |
| Missing data | 59 (1.9) | — | — | |
Abbreviation: SD, standard deviation.
a
χ2 tests were used to examine the differences between myopia and no myopia group based on the above-mentioned categorical variables, and a t-test was used to examine the refractive error and age differences between myopia and no myopia group.
b
Refractive error data and age data are presented as the mean (±SD).