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Table 3 Associations between birth weight and an inter-quartile range in air pollution metrics, for pregnancy-long exposures (a)

From: Investigating the association between birth weight and complementary air pollution metrics: a cohort study

   

Low birth weight

Mean birth weight in grams

Air pollution metrics

Inter-quartile range (IQR) in air pollution metrics

Number of subjects

Odds ratio per IQR increase in air pollution metrics

95% confidence interval

p value

Change for per IQR increase in air pollution metrics

95% confidence interval

p value

Monitoring station measurements, nearest station approach without distance restrictions (b)

NO 2

11.87

68,303

0.85

0.76

0.94

< 0.01

36.24

30.50

41.98

< 0.01

NO x

27.70

68,303

0.93

0.86

1.00

0.06

25.31

20.84

29.78

< 0.01

NO

17.90

68,303

0.95

0.89

1.02

0.20

20.27

16.23

24.32

< 0.01

CO

0.48

68,303

0.96

0.88

1.04

0.28

22.79

18.23

27.35

< 0.01

PM 10

6.76

68,303

0.94

0.87

1.01

0.09

20.74

16.68

24.79

< 0.01

PM 2.5

5.10

61,623

0.93

0.84

1.02

0.11

26.83

21.56

32.11

< 0.01

O 3

11.50

68,303

1.13

1.02

1.25

0.01

−31.36

−36.82

−25.89

< 0.01

Land Use Regression model predictions (b)

NO 2

9.34

68,303

0.94

0.86

1.02

0.13

16.59

12.01

21.16

< 0.01

NO x

25.24

68,303

0.98

0.91

1.06

0.66

9.42

5.25

13.59

< 0.01

CALINE4 predictions (b)

NO x

5.65

67,043

0.97

0.90

1.04

0.35

14.10

10.29

17.91

< 0.01

CO

0.08

67,043

0.96

0.90

1.04

0.31

15.09

11.27

18.91

< 0.01

PM 2.5

1.36

67,043

0.99

0.92

1.06

0.74

5.94

2.32

9.57

< 0.01

Traffic density, within buffers of different distances around roads (b)

50 m

12.91

68,303

1.00

1.00

1.01

0.52

0.06

−0.21

0.32

0.68

75 m

35.91

68,303

1.01

0.99

1.02

0.24

−0.21

−1.12

0.69

0.64

100 m

53.91

68,303

1.02

1.00

1.05

0.06

−0.51

−2.00

0.97

0.50

150 m

74.30

68,303

1.05

1.01

1.08

0.01

−0.34

−2.43

1.75

0.75

200 m

84.33

68,303

1.05

1.01

1.09

0.01

0.06

−2.29

2.42

0.96

250 m

81.34

68,303

1.04

1.00

1.08

0.05

0.35

−1.95

2.64

0.77

300 m

76.57

68,303

1.02

0.99

1.06

0.21

0.22

−1.67

2.11

0.82

Distance to the nearest road (b)

Freeways

1766.80

68,303

1.04

0.96

1.14

0.35

−7.80

−12.50

−3.09

< 0.01

Major roads

253.05

68,303

0.94

0.87

1.01

0.07

−1.95

−5.42

1.51

0.27

  1. a) Adjusted for maternal age, length of gestation and poverty using smoothing splines and maternal race/ethnicity, insurance, parity, and gender of the infant as categorical variables.
  2. b) The units are parts per million for CO, parts per billion for NO, NO2, NOx, and O3, and μg.m-3 for PM10 and PM2.5. Concentrations are averages, across the pregnancy period, derived from daily 24 h- mean concentrations for NO2, NO, NOx, CO, PM10 and PM2.5 and from daily mean concentrations from 10 am to 6 pm for O3. The unit for traffic density is vehicle number per day/meter. The unit for distance to road is meters.