Variables | MLBW | No MLBW | p value |
---|---|---|---|
 | n = 53,276 (%) | n = 1,323,930 (%) |  |
Sex |  < 0.0001a | ||
 Female | 32,080 (60.21) | 634,531 (47.93) |  |
 Male | 21,196 (39.79) | 689,399 (52.07) |  |
Agec | |||
 Mean ± SD | 3.27 + 2.31 | 3.39 + 2.32 |  <0.0001b |
Economic status |  < 0.0001a | ||
 Low income | 3785 (7.10) | 66,293 (5.01) |  |
Confounders | |||
 Blindness and low vision | 3 (0.01) | 26 (0.002) | 0.0705a |
 Epilepsy | 241 (0.45) | 3101 (0.23) |  < 0.0001a |
 Fetal and neonatal hemorrhage | 35 (0.06) | 236 (0.02) |  < 0.0001a |
 Communicating hydrocephalus | 10 (0.02) | 83 (0.01) | 0.0006a |
 Intrauterine hypoxia and birth asphyxia | 38 (0.07) | 201 (0.02) |  < 0.0001a |
 Other perinatal jaundice | 54 (0.10) | 714 (0.05) |  < 0.0001a |
 Microcephalus | 35 (0.07) | 123 (0.01) |  < 0.0001a |
 Patent ductus arteriosus | 459 (0.86) | 3069 (0.23) |  < 0.0001a |
 Pneumonia | 1707 (3.20) | 36,133 (2.73) |  < 0.0001a |
 Pneumothorax | 9 (0.02) | 135 (0.01) | 0.1383a |
 Other respiratory conditions of fetus and newborn | 338 (0.63) | 1593 (0.12) |  < 0.0001a |