Table 1 Population characteristics of the LIFE Child study sample
Population Characteristics | 3–10 years | 11–18 years |
|---|---|---|
N = 620 | N = 796 | |
Mean age (years): | 7.3 | 14.9 |
Sex: | ||
Female | 296 (47.7%) | 390 (49.0%) |
Male | 324 (52.3%) | 406 (51.0%) |
Myopia: | ||
Myopic | 24 (3.9%) | 171 (21.5%) |
Non-myopic | 596 (96.1%) | 625 (78.5%) |
Socioeconomic status: | ||
Low | 65 (10.8%) | 105 (15.2%) |
Medium | 272 (45.3%) | 366 (52.8%) |
High | 263 (43.8%) | 222 (32.0%) |
Urban environment: | ||
No | 125 (20.4%) | 178 (26.1%) |
Yes | 488 (79.6%) | 505 (73.9%) |
Time outdoors frequency: | ||
Every day | 461 (79.2%) | 264 (45.4%) |
Every two days | 68 (11.7%) | 147 (25.3%) |
Two days per week | 39 (6.7%) | 132 (22.7%) |
Once per week | 14 (2.4%) | 38 (6.5%) |
Time outdoors duration: | ||
< 1 h | 58 (10.0%) | 88 (15.1%) |
1–2 h | 296 (50.9%) | 327 (56.1%) |
3–4 h | 169 (29.0%) | 140 (24.0%) |
> 4 h | 59 (10.1%) | 28 (4.8%) |
Near work frequency: | ||
Every day | 364 (65.9%) | 194 (40.2%) |
Every two days | 110 (19.9%) | 120 (24.9%) |
Two days per week | 53 (9.6%) | 88 (18.3%) |
Once per week | 25 (4.5%) | 80 (16.6%) |
Near work duration: | ||
< 1 h | 373 (67.6%) | 237 (49.6%) |
1–2 h | 164 (29.7%) | 219 (45.8%) |
3–4 h | 14 (2.5%) | 18 (3.7%) |
> 4 h | 1 (0.2%) | 4 (0.8%) |