Table 1. Characteristics of the study population: Singleton live births in Alberta from April 1, 2005 to March 31, 2010.
| Characteristic | N | % |
|---|---|---|
| Live singletons | 206,994 | 100.0 |
| Sex | ||
| Female | 100,795 | 48.7 |
| Male | 105,967 | 51.2 |
| Missing data | 232 | 0.1 |
| Adverse birth group | ||
| Reference group | 149,743 | 72.3 |
| Moderate/late PTB (32–26) | 15,861 | 7.7 |
| Very PTB (<32) | 3,107 | 1.5 |
| SGA at term | 16,241 | 7.9 |
| LGA at term | 18,134 | 8.8 |
| Missing data | 3,908 | 1.9 |
| 5-min Apgar | ||
| Reassuring (7–10) | 194,943 | 94.2 |
| Moderately abnormal (4–6) | 3,552 | 1.7 |
| Low (0–3) | 832 | 0.4 |
| Missing data | 7,667 | 3.7 |
| Significant resuscitation measures | 18,942 | 9.2 |
| Bronchopulmonary dysplasia | 128 | 0.1 |
| Material deprivation (quintiles) | ||
| Q1 (least deprived) | 39,806 | 19.2 |
| Q2 | 38,931 | 18.8 |
| Q3 | 39,007 | 18.8 |
| Q4 | 37,635 | 18.2 |
| Q5 (most deprived) | 43,193 | 20.9 |
| Missing data | 8,422 | 4.1 |
| Social Deprivation (quintiles) | ||
| Q1 (least deprived) | 27,353 | 13.2 |
| Q2 | 39,990 | 19.3 |
| Q3 | 43,927 | 21.2 |
| Q4 | 46,120 | 22.3 |
| Q5 (most deprived) | 41,182 | 19.9 |
| Missing data | 8,422 | 4.1 |
| Deaths at follow-up | 183 | 0.1 |
Reference group = appropriate-for-gestational age infants born at term; LGA = large for gestational age. PTB = preterm birth. SGA = small for gestational age.