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Table 3 Correlation coefficients for the food frequency questionnaires (FFQ1 and FFQ2) and assisted food records (FRs) for comparative validity

From: Reproducibility and comparative validity of a food frequency questionnaire for Australian children and adolescents

Energy & Nutrients

Average of FFQ1 and FFQ2 vs Assisted FRs

(n = 101)

FFQ2 vs Assisted FRs

(n = 113)

 

Unadjusted (crude)

Transformed

De-attenuated, transformed

Energy-adjusted, transformed

De-attenuated, Energy-adjusted, transformed

Unadjusted (crude)

Transformed

De-attenuated, transformed

Energy-adjusted, transformed

De-attenuated, Energy-adjusted, transformed

Energy (kJ)

0.29 **

0.29 **

0.32

-

-

0.21 *

0.20 *

0.22

-

-

Protein (g)

0.27 *

0.27 *

0.32

0.25 *

0.29

0.15

0.15

0.18

0.22 *

0.26

Fat (g)

0.34 **

0.34 **

0.39

0.30 **

0.34

0.27 **

0.27 **

0.31

0.46 **

0.53

Sat Fat (g)

0.39 **

0.39 **

0.44

0.41 **

0.46

0.33 **

0.31 **

0.35

0.46 **

0.52

Poly Fat (g)

0.20 *

0.20 *

0.25

0.03

0.04

0.14

0.16

0.20

0.17

0.21

Mono Fat (g)

0.28 **

0.31 **

0.36

0.18

0.21

0.25 *

0.26 **

0.30

0.38 **

0.44

Carbohydrate (g)

0.25 *

0.26 *

0.29

0.26 *

0.29

0.23 *

0.22 *

0.24

0.42 **

0.47

Sugars (g)

0.25 *

0.27 *

0.30

0.22 *

0.25

0.24 *

0.27 **

0.30

0.37 **

0.41

Fibre (g)

0.44 **

0.42 **

0.48

0.37 **

0.42

0.29 **

0.29 **

0.33

0.31 **

0.35

Thiamin (mg)

0.36 **

0.41

0.45

0.31 **

0.34

0.19 *

0.23 *

0.26

0.31 **

0.35

Riboflavin (mg)

0.38 **

0.45 **

0.51

0.46 **

0.52

0.25 *

0.30 **

0.34

0.47 **

0.53

Niacin (mg)

0.28 **

0.31 **

0.36

0.21 *

0.24

0.12

0.14

0.16

0.18

0.21

Niacin equiv (mg)

0.31 **

0.29 **

0.33

0.19

0.22

0.13

0.13

0.15

0.15

0.17

Vitamin C (mg)

0.25 *

0.25 *

0.28

0.36 **

0.41

0.28 **

0.29 **

0.33

0.42 **

0.48

Folate (μg)

0.46 **

0.50 **

0.55

0.48 **

0.53

0.25 *

0.31 **

0.34

0.46 **

0.51

Vitamin A (μg)

0.28 **

0.31 **

0.36

0.25 *

0.29

0.19

0.18

0.21

0.24 *

0.27

Retinol (μg)

0.17

0.22 *

0.25

0.03

0.03

0.09

0.08

0.09

0.03

0.03

Betacarotene (μg)

0.27 *

0.36 **

0.42

0.41 **

0.48

0.29 **

0.30 **

0.34

0.39 **

0.45

Magnesium (mg)

0.38 **

0.40 **

0.44

0.50 **

0.55

0.28 **

0.28 **

0.31

0.51 **

0.56

Calcium (mg)

0.43 **

0.47 **

0.52

0.51 **

0.56

0.35 **

0.37 **

0.41

0.46 **

0.51

Iron (mg)

0.44 **

0.42 **

0.46

0.39 **

0.43

0.34 **

0.33 **

0.37

0.46 **

0.51

Zinc (mg)

0.28 **

0.26 *

0.31

0.25 *

0.30

0.18

0.15

0.18

0.27 **

0.32

Measure of central tendency

0.285 §

0.34 §§

0.38 §§

0.30 §§

0.34 §§

0.245 §

0.24 §§

0.27 §§

0.34 §§

0.39 §§

  1. Spearmans correlations undertaken in unadjusted (crude) data. Pearsons correlations undertaken on all other data (square-root transformed).
  2. * denotes p-value < 0.05; ** denotes p-value < 0.01; § denotes median; §§ denotes mean.