Table 2 Characteristics of the study subjects (n = 105, 988).

From: Ozone and Other Air Pollutants and the Risk of Congenital Heart Defects

Item

Infants without any malformations (N = 105,800)

Congentital heart defects (N = 188)

Maternal age (years)

ā€ƒ<20

19813 (18.73)

29 (15.43)

ā€ƒ20–25

53060 (50.15)

102 (54.26)

ā€ƒ25–30

25237 (23.85)

46 (24.47)

ā€ƒ>30

7690 (7.27)

11 (5.85)

Maternal education (years)

ā€ƒ<12

15578 (14.76)

31 (16.49)

ā€ƒ12–15

45917 (43.51)

78 (41.49)

ā€ƒ>15

44042 (41.73)

79 (42.02)

ā€ƒMissing

263

Ā 

Parity

ā€ƒ1

81098 (76.65)

144 (76.60)

ā€ƒ>1

24702 (23.35)

44 (23.40)

Season of conception

ā€ƒSpring

25662 (24.26)

38 (20.21)

ā€ƒSummer

25042 (23.67)

47 (25.00)

ā€ƒAutumn

26833 (25.36)

46 (24.47)

ā€ƒWinter

28263 (26.71)

57 (30.32)

Infant sex

ā€ƒMale

56355 (53.27)

97 (52.43)

ā€ƒFemale

49437 (46.73)

88 (47.57)

Type of birth

ā€ƒLive birth

105421 (99.64)

29 (15.42)

ā€ƒStillbirth

372 (0.35)

159 (84.57)

ā€ƒfetal deaths

7 (0.01)

Ā