Table 4 Adjusted risk ratios and 95% confidence intervals for preterm birth by interquartile range change of NO₂, O₃, PM_2.5 modified by diet

Trimester 1

NO ₂ ^a

kcal ^k

1.00

(0.69, 1.44)

1.00

(0.70, 1.43)

0.93

(0.67, 1.27)

fat ^l

1.09

(0.77, 1.53)

1.08

(0.76, 1.53)

0.94

(0.63, 1.39)

dfat ^m

1.17

(0.83, 1.63)

1.15

(0.81, 1.62)

0.99

(0.70, 1.41)

O ₃ ^b

kcal

0.91

(0.58, 1.44)

0.89

(0.56, 1.42)

0.99

(0.46, 2.12)

fat

0.84

(0.55, 1.29)

0.81

(0.52, 1.26)

0.97

(0.47, 2.00)

sfat

0.87

(0.58, 1.32)

0.89

(0.59, 1.33)

1.04

(0.65, 1.65)

H PM _2.5  ^cd

kcal

0.93

(0.63, 1.37)

0.93

(0.64, 1.36)

0.94

(0.54, 1.61)

fat

0.85

(0.58, 1.24)

0.84

(0.57, 1.23)

0.86

(0.48, 1.53)

sfat

0.91

(0.63, 1.31)

0.91

(0.63, 1.31)

0.93

(0.57, 1.54)

C PM _2.5 ^ce

kcal

0.97

(0.68, 1.37)

0.97

(0.69, 1.36)

1.04

(0.61, 1.75)

fat

0.91

(0.64, 1.27)

0.89

(0.63, 1.26)

0.98

(0.56, 1.71)

sfat

0.94

(0.68, 1.31)

0.94

(0.68, 1.31)

1.01

(0.61, 1.66)

Trimester 2

NO ₂

kcal

0.96

(0.67, 1.38)

1.00

(0.69, 1.45)

1.03

(0.69, 1.55)

fat

0.95

(0.67, 1.35)

0.97

(0.68, 1.38)

0.97

(0.65, 1.44)

sfat

1.05

(0.76, 1.47)

1.07

(0.77, 1.50)

1.10

(0.75, 1.61)

O ₃

kcal

0.98

(0.63, 1.53)

0.95

(0.62, 1.46)

0.77

(0.39, 1.49)

fat

1.12

(0.74, 1.69)

1.08

(0.71, 1.65)

0.80

(0.40, 1.64)

sfat

1.03

(0.69, 1.53)

1.00

(0.67, 1.50)

0.79

(0.43, 1.47)

H PM _2.5

kcal

-- ^j

--

--

--

--

--

fat

0.87

(0.59, 1.28)

0.83

(0.55, 1.24)

0.72

(0.40, 1.30)

sfat

0.88

(0.60, 1.29)

0.84

(0.57, 1.25)

0.77

(0.44, 1.36)

C PM _2.5

kcal

--

--

--

--

--

--

fat

0.91

(0.64, 1.29)

0.88

(0.62, 1.26)

0.73

(0.40, 1.33)

sfat

0.89

(0.63, 1.27)

0.87

(0.61, 1.24)

0.82

(0.48, 1.41)

Trimester 3

NO ₂

kcal

0.80

(0.57, 1.13)

0.82

(0.58, 1.16)

0.87

(0.57, 1.31)

fat

0.79

(0.56, 1.11)

0.79

(0.55, 1.13)

0.83

(0.55, 1.26)

sfat

0.88

(0.63, 1.23)

0.88

(0.63, 1.23)

0.95

(0.65, 1.39)

O ₃

kcal

1.25

(0.77, 2.04)

1.24

(0.76, 2.01)

1.51

(0.62, 3.64)

fat

1.34

(0.83, 2.16)

1.34

(0.83, 2.17)

1.43

(0.60, 3.38)

sfat

1.33

(0.84, 2.12)

1.31

(0.82, 2.10)

1.36

(0.58, 3.17)

H PM _2.5

kcal

1.07

(0.71, 1.60)

1.05

(0.71, 1.54)

0.92

(0.55, 1.55)

fat

1.35

(0.97, 1.89)

1.34

(0.96, 1.88)

1.07

(0.65, 1.76)

sfat

1.14

(0.81, 1.63)

1.12

(0.79, 1.58)

0.95

(0.76, 1.18)

C PM _2.5

kcal

1.15

(0.78, 1.67)

1.13

(0.78, 1.64)

1.06

(0.61, 1.83)

fat

1.46

(1.05, 2.02)

1.40

(0.96, 2.05)

1.21

(0.70, 2.08)

sfat

1.19

(0.86, 1.65)

1.17

(0.84, 1.64)

1.00

(0.70, 1.45)