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Table 3 Diet-related environmental impact according to the food frequency questionnaire (FFQ) and two replicates of the 24-h recall (24hR, with intra-class correlation coefficient) and group level bias, with correlation between the methods (crude, adjusted, de-attenuated) and attenuation coefficient (crude, adjusted)a for observed and energy-adjusted values standardised to a 2000 kcal diet

From: FFQ versus repeated 24-h recalls for estimating diet-related environmental impact

 

FFQ

2 replicates of 24hR

Correlation coefficient (24hR with FFQ)

Attenuation coefficient λ1

Dietary variables

Mean

(SD)

Mean

(SD)

ICC

%bias

Crude (95%CI)

Adjustedb(95%CI)

De-attenuated (95%CI)

Crude (SE)

Adjustedb (SE)

Observed values

 Energy, kcal/d

2139

(532)

2012

(583)

0.31

6.3

0.47

(0.43; 0.52)

0.38

(0.33; 0.43)

0.68

(0.59; 0.77)

0.52

(0.03)

0.42

(0.03)

 Protein, g/d

77.6

(18.5)

78.2

(23.5)

0.27

−0.8

0.46

(0.41; 0.50)

0.39

(0.34; 0.44)

0.75

(0.65; 0.84)

0.58

(0.03)

0.51

(0.04)

 GHGE, kgCO2e/d

3.50

(0.87)

3.64

(1.46)

0.21

−3.8

0.35

(0.30; 0.40)

0.30

(0.25; 0.35)

0.66

(0.54; 0.77)

0.59

(0.05)

0.53

(0.05)

 FE, MJ/d

30.19

(6.71)

31.10

(9.20)

0.28

−2.9

0.45

(0.40; 0.49)

0.40

(0.35;0.44)

0.75

(0.66; 0.84)

0.62

(0.04)

0.57

(0.04)

 LU, m2*year/d

4.01

(1.08)

4.15

(1.82)

0.17

−3.4

0.37

(0.32; 0.42)

0.31

(0.26; 0.36)

0.75

(0.62; 0.87)

0.63

(0.05)

0.56

(0.05)

 pReCiPe

0.41

(0.10)

0.43

(0.16)

0.19

−4.7

0.39

(0.34; 0.43)

0.33

(0.28; 0.38)

0.76

(0.64; 0.87)

0.62

(0.04)

0.56

(0.05)

Energy-adjusted values by regression residuals of observed values on energy (observed residuals)

 Protein, g/d

73.5

(10.3)

77.9

(14.2)

0.20

−5.6

0.35

(0.30; 0.40)

0.33

(0.28; 0.38)

0.75

(0.63; 0.86)

0.49

(0.04)

0.46

(0.04)

 GHGE, kgCO2e/d

3.33

(0.61)

3.63

(1.24)

0.12

−8.3

0.26

(0.20; 0.31)

0.23

(0.17; 0.28)

0.66

(0.50; 0.81)

0.52

(0.06)

0.48

(0.06)

 FE, MJ/d

28.82

(4.21)

30.98

(6.77)

0.22

−7.0

0.39

(0.34; 0.43)

0.35

(0.30; 0.40)

0.76

(0.65; 0.86)

0.62

(0.04)

0.59

(0.05)

 LU, m2*year/d

3.80

(0.71)

4.14

(1.56)

0.13

−8.2

0.30

(0.24; 0.35)

0.27

(0.21; 0.32)

0.73

(0.58; 0.88)

0.65

(0.06)

0.60

(0.06)

 pReCiPe,

0.39

(0.07)

0.43

(0.14)

0.14

−9.3

0.30

(0.24; 0.35)

0.26

(0.21; 0.32)

0.71

(0.57; 0.85)

0.61

(0.06)

0.56

(0.06)

Energy-adjusted values by regression residuals of densities on energy (density residuals)

 Protein density, %

14.9

(2.0)

15.9

(3.1)

0.20

−6.3

0.37

(0.31; 0.41)

0.35

(0.29; 0.40)

0.78

(0.66; 0.89)

0.57

(0.04)

0.54

(0.04)

 GHGEdensity,kgCO2e/d

3.38

(0.60)

3.73

(1.30)

0.19

−9.4

0.28

(0.23; 0.33)

0.25

(0.20; 0.30)

0.59

(0.46; 0.71)

0.61

(0.06)

0.57

(0.06)

 FE density, MJ/d

29.31

(4.09)

32.14

(7.62)

0.30

−8.8

0.39

(0.34; 0.44)

0.36

(0.31; 0.41)

0.66

(0.56; 0.74)

0.73

(0.05)

0.69

(0.05)

 LU density, m2*year/d

3.83

(0.70)

4.24

(1.72)

0.21

−9.7

0.30

(0.24; 0.35)

0.27

(0.21; 0.32)

0.59

(0.47; 0.71)

0.73

(0.07)

0.67

(0.07)

 pReCiPe density

0.40

(0.06)

0.44

(0.15)

0.22

−9.1

0.31

(0.26; 0.36)

0.28

(0.22; 0.33)

0.59

(0.48; 0.71)

0.70

(0.06)

0.65

(0.07)

  1. ICC, intra class correlation coefficient; GHGE, greenhouse gas emissions; FE, fossil energy use; LU, land use; pReCiPe, a weighted summary score for GHGE, FE, and LU; % bias, group-level bias calculated as (mean intake FFQ /mean intake 24hR)×100; 100; correlation coefficient (95%CI) estimated as the Pearson correlation coefficient; de-attenuated correlation coefficient (95%CI) estimated as the Pearson correlation coefficient/√ICC24hR; Attenuation coefficient λ1 (SE) estimated as the slope in the linear regression of the 24hR on the FFQ using linear mixed models to account for within-person day-to-day variability
  2. aMean values with their standard deviations, correlation coefficient with its 95% confidence intervals, attenuation coefficient with its standard error
  3. bAdjusted for age, gender and BMI
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Nutrition Journal

ISSN: 1475-2891

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