Table 1 Characteristics of the study subjects
Elementary School (n = 1728) | Secondary school (n = 2114) | |
|---|---|---|
Gender, % (n) | ||
Boys | 54.9 (948) | 49.9 (1054) |
Girls | 45.1 (780) | 50.1 (1060) |
Age | ||
Mean (SD) | 8.7 (0.61) | 14.8 (0.82) |
Median | 8.7 | 15.0 |
Range | 7–15 | 11–18 |
Ethnicity | ||
Han | 16.6 (287) | 16.6 (351) |
Hani | 68.2 (1178) | 62.5 (1321) |
Yi | 9.3 (162) | 12.0 (253) |
Others | 5.9 (102) | 8.9 (189) |
BMI (SD) | 16.2 (2.82) | 19.7 (2.89) |
Myopia, n(%) | ||
Presence | 2.5 (43) | 30.5 (644) |
Absence | 97.5 (1685) | 69.5 (1470) |