Table 2 Characteristics of the study subjects (nā=ā105, 988).
From: Ozone and Other Air Pollutants and the Risk of Congenital Heart Defects
Item | Infants without any malformations (Nā=ā105,800) | Congentital heart defects (Nā=ā188) |
---|---|---|
Maternal age (years) | ||
ā<20 | 19813 (18.73) | 29 (15.43) |
ā20ā25 | 53060 (50.15) | 102 (54.26) |
ā25ā30 | 25237 (23.85) | 46 (24.47) |
ā>30 | 7690 (7.27) | 11 (5.85) |
Maternal education (years) | ||
ā<12 | 15578 (14.76) | 31 (16.49) |
ā12ā15 | 45917 (43.51) | 78 (41.49) |
ā>15 | 44042 (41.73) | 79 (42.02) |
āMissing | 263 | Ā |
Parity | ||
ā1 | 81098 (76.65) | 144 (76.60) |
ā>1 | 24702 (23.35) | 44 (23.40) |
Season of conception | ||
āSpring | 25662 (24.26) | 38 (20.21) |
āSummer | 25042 (23.67) | 47 (25.00) |
āAutumn | 26833 (25.36) | 46 (24.47) |
āWinter | 28263 (26.71) | 57 (30.32) |
Infant sex | ||
āMale | 56355 (53.27) | 97 (52.43) |
āFemale | 49437 (46.73) | 88 (47.57) |
Type of birth | ||
āLive birth | 105421 (99.64) | 29 (15.42) |
āStillbirth | 372 (0.35) | 159 (84.57) |
āfetal deaths | 7 (0.01) | Ā |