Table 4 Smoking cohort, birthweight regression analysis.

From: Effects of PM2.5 exposure during high bushfire smoke days on birthweight and gestational age in Hunter New England, NSW, Australia. A study on pregnant people who smoke and don’t smoke

Variable

Level

Univariate

Full model (R2a = 0.58)

Parsimonious model (R2a = 0.57)

β

95% CI

P Value

β

95% CI

P Value

β

95% CI

P Value

Days of PM2.5 Exposure (> 25 µg/m 3 )

-0.96

-2.42, 0.50

0.199

-0.63

-1.70, 0.44

0.250

-1.33

-2.33, -0.33

0.009

Gestation (Days)

28.67

27.71, 29.63

< 0.001

26.37

25.48, 27.26

< 0.001

26.20

25.33, 27.07

< 0.001

Gender

Female

-110.44

-145.61, -75.28

< 0.001

-143.40

-166.53, -120.27

< 0.001

-142.17

-165.35, -118.99

< 0.001

Male

Ref

        

Diabetes

Yes

36.67

-18.58, 91.93

0.193

107.13

69.47, 144.80

< 0.001

   

Unknown

-39.09

-209.50, 131.33

0.653

27.68

-89.19, 144.56

0.642

   

No

Ref

        

Foetal Growth Restriction

Yes

-919.22

-981.81, -856.63

< 0.001

-555.03

-602.16, -507.89

< 0.001

-562.44

-609.70, -515.18

< 0.001

Clinical Suspicion

-608.93

-680.31, -537.54

< 0.001

-442.10

-494.67, -389.52

< 0.001

-447.29

-499.96, -394.63

< 0.001

Unknown

-714.66

-1044.10, -385.23

< 0.001

-455.06

-704.84, -205.28

< 0.001

-486.14

-727.47, -244.81

< 0.001

No

Ref

        

Ethnicity

Non-Indigenous

79.05

38.11, 119.99

< 0.001

28.60

0.46, 56.74

0.046

   

Unknown

16.48

-233.26, 266.21

0.897

44.47

-121.39, 210.32

0.599

   

Indigenous

Ref

        

Previous Pregnancy

Yes

22.39

-16.81, 61.60

0.263

101.90

73.24, 130.56

< 0.001

84.67

58.48, 110.87

< 0.001

No

Ref

        

Hypertension

Yes

-124.43

-209.87, -38.99

0.004

4.08

-52.62, 60.77

0.888

   

Unknown

182.38

-517.77, 153.02

0.286

-148.94

-373.13, 75.25

0.193

   

No

Ref

        

Anaemia

Yes

85.56

37.92, 133.20

< 0.001

52.42

21.11, 83.74

0.001

52.88

21.55, 84.22

0.001

Unknown

2.65

-37.21, 42.52

0.896

-39.44

-67.577, -11.31

0.006

-31.33

-58.80, -3.86

0.025

No

Ref

        

Birth Type

Instrumental Birth

73.46

2.16, 144.76

0.043

3.63

-44.41, 51.66

0.882

   

Caesarean Birth

-93.82

-133.267, -54. 37

< 0.001

-5.31

-31.97, 21.34

0.696

   

Vaginal Birth

Ref

        

Maternal Age

 

-4.08

-7.08, -1.08

0.008

-3.16

-5.32, -0.20

0.004

   

Maternal BMI

 

17.13

14.61, 19.64

< 0.001

10.00

8.22, 11.78

< 0.001

10.90

9.19, 12.61

< 0.001

PM2.5 Tower Location

Beresfield

208.53

102.34, 314.72

< 0.001

121.90

46.32, 197.49

0.002

   

Gunnedah

319.82

160.53, 479.10

< 0.001

130.43

23.46, 237.41

0.017

   

Muswellbrook

294.47

166.17, 422.77

< 0.001

134.90

46.12, 223.68

0.003

   

Narrabri

91.35

-75.29, 257.99

0.283

89.53

-23.26, 202.33

0.120

   

Singleton

278.05

151.06, 405.03

< 0.001

95.50

6.96, 184.04

0.035

   

Tamworth

176.82

63.92, 289.77

0.002

95.48

16.72, 174.24

0.018

   

Armidale

Ref

        
  1. Key: ref: reference variable for which all other levels within the variable are assessed. “PM2.5 tower” denotes the suburb location of the air quality monitoring site from which the exposure variables were collected.
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