Characteristics | Cases N = 1670 | Controls N = 6680 | Overall N = 8350 | P-value |
---|---|---|---|---|
Age at index date in months [(median, (IQR)] | 4.0 (2.0–13.0) | 4.0 (2.0–13.0) | 4.0 (2.0–13.0) | 1 |
Female [N, (%)] | 649 (44.2%) | 2596 (44.2%) | 3245 (44.2%) | 1 |
Number of live births per mother (mean ± SD) | 2.5 ± 1.1 | 2.2 ± 1.0 | 2.2 ± 1.0 | <.001 |
Neighbourhood Income quintile [N (%)] | ||||
1 - lowest | 351 (23.9%) | 1205 (20.5%) | 1556 (21.2%) | 0.06 |
2 | 265 (18.1%) | 1160 (19.8%) | 1425 (19.4%) | |
3 | 307 (20.9%) | 1260 (21.5%) | 1567 (21.3%) | |
4 | 315 (21.5%) | 1272 (21.7%) | 1587 (21.6%) | |
5 - highest | 230 (15.7%) | 975 (16.6%) | 1205 (16.4%) | |
Rural [N (%)] | 158 (10.8%) | 552 (9.4%) | 710 (9.7%) | 0.11 |
Distance to nearest acute care hospital in km (Mean ± SD) | 6.0 ± 6.3 | 5.9 ± 7.2 | 5.9 ± 7.0 | 0.49 |
Ecozones [N (%)] | ||||
South | 1396 (95.1%) | 5597 (95.3%) | 6993 (95.3%) | 0.72 |
Northa | 72 (4.9%) | 275 (4.7%) | 347 (4.7%) | |
Annual AQHIb (Mean ± SD) | 3.2 ± 0.3 | 3.2 ± 0.3 | 3.2 ± 0.3 | <.001 |
Yearly mean of daily max NO2c (ppb) (Mean ± SD) | 19.5 ± 4.7 | 20.3 ± 4.9 | 20.1 ± 4.8 | <.001 |
Yearly mean of daily max O3 (ppb) (Mean ± SD) | 39.9 ± 2.0 | 39.8 ± 1.8 | 39.8 ± 1.9 | 0.07 |
Yearly mean of daily max PM2.5c (μg/m3) (Mean ± SD) | 15.2 ± 1.9 | 15.2 ± 1.7 | 15.2 ± 1.7 | 0.37 |
Mean of minimum daily temperature during 7–13 prior to index date, (°C) (Mean ± SD) | − 4.6 ± 4.8 | − 2.4 ± 6.6 | −2.8 ± 6.3 | <.001 |