Table 5 Complete cohort, gestation (days) 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 = 0.47)

Parsimonious model (R2a = 0.46)

β

95% CI

P Value

β

95% CI

P Value

β

95% CI

P Value

Days of PM2.5 Exposure (> 25 µg/m 3 )

0.01

-0.00, 0.02

0.18

0.02

0.01, 0.03

0.001

0.01

0.00, 0.02

0.003

Birthweight (g)

0.01

0.01, 0.01

< 0.001

0.02

0.01, 0.02

< 0.001

0.02

0.02, 0.02

< 0.001

Gender

Female

0.64

0.33, 0.95

< 0.001

2.24

2.00, 2.47

< 0.001

2.29

2.06, 2.53

< 0.001

Male

Ref

        

Smoking

Yes

-3.46

-3.87, -3.05

< 0.001

0.57

0.25, 0.88

< 0.001

0.58

0.27, 0.89

< 0.001

No

Ref

        

Diabetes

Yes

-7.09

-7.57, -6.62

< 0.001

-4.47

-4.83, -4.10

< 0.001

   

Unknown

-0.42

-2.86, 2.02

0.738

1.00

-0.81, 2.81

0.280

   

No

Ref

        

Foetal Growth Restriction

Yes

-14.80

-15.65, -13.94

< 0.001

1.04

0.36, 1.72

0.003

1.16

0.47, 1.85

0.001

Clinical Suspicion

-6.04

-7.06, -5.03

< 0.001

4.00

3.23, 4.78

< 0.001

4.06

3.27, 4.84

< 0.001

Unknown

-9.63

-14.48, -4.77

< 0.001

3.26

-0.38, 6.90

< 0.001

4.76

1.10, 8.43

0.011

No

Ref

        

Ethnicity

Non-Indigenous

1.76

1.27, 2.25

< 0.001

0.61

0.24, 0.98

0.001

   

Unknown

0.67

-1.27, 2.61

0.500

0.28

-1.15, 1.72

0.701

   

Indigenous

Ref

        

Previous Pregnancy

Yes

-1.62

-1.94, -1.30

< 0.001

-2.95

-3.21, -2.69

< 0.001

-2.77

-3.02, -2.53

< 0.001

No

Ref

        

Hypertension

Yes

-8.07

-8.72, -7.42

< 0.001

-3.39

-3.88, -2.89

< 0.001

   

Unknown

-4.18

-9.43, 1.06

0.118

1.86

-2.02, 5.74

0.348

   

No

Ref

        

Anaemia

Yes

0.67

0.25, 1.09

0.002

-0.21

-0.52, 0.09

0.176

   

Unknown

0.72

0.37, 1.08

< 0.001

0.77

0.49, 1.04

< 0.001

   

No

Ref

        

Birth Type

Instrumental Birth

2.34

1.79, 2.90

< 0.001

1.15

0.73, 1.57

< 0.001

1.06

0.63, 1.48

< 0.001

Caesarean Birth

-4.28

-4.62, -3.94

< 0.001

-2.85

-3.11, -2.59

< 0.001

-3.15

-3.41, -2.89

< 0.001

Vaginal Birth

Ref

        

Maternal Age

 

-0.13

-0.16, -0.10

< 0.001

0.00

-0.01, − 0.03

0.506

   

Maternal BMI

 

-0.11

-0.14, -0.09

< 0.001

-0.13

-0.14, -0.11

< 0.001

-0.19

-0.21, -0.18

< 0.001

PM2.5 Tower Location

Beresfield

0.07

-0.86, 1.00

0.883

-1.36

-2.08, -0.64

< 0.001

   

Gunnedah

0.11

-1.34, 1.57

0.880

-0.38

-1.46, 0.70

0.488

   

Muswellbrook

0.66

-0.55, 1.87

0.283

-0.66

-1.46, 0.70

0.158

   

Narrabri

-1.99

-3.58, -0.40

0.014

-2.27

-1.57, 0.26

< 0.001

   

Singleton

1.49

0.40, 2.58

0.007

-0.76

-1.59, 0.07

0.074

   

Tamworth

-0.89

-1.91, 0.13

0.087

-1.40

-2.18, -0.62

< 0.001

   

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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