Table 4

Measures of reproducibility for the daily intake of energy and selected nutrients in the test and retest food frequency questionnaire (FFQ), n = 1370

Test (FFQ1)

Retest (FFQ2)

Within person differences (FFQ1-FFQ2)

Pearson

Spearman





Nutrient

Mean

SDa

Mean

SD

Mean

95% CIb

Mean ± 2 SDc

r

95% CI

rs


Energy (kJ)

6571

1748

6400

1732

170.2

(91.5, 249.0)

(-2801, 3142)

0.64

(0.60, 0.67)

0.63

Protein (g)

73.6

21.3

71.5

21.0

2.1

(1.0, 3.1)

(-36, 40)

0.60

(0.56, 0.63)

0.60

Total fat (g)

60.0

20.1

58.4

19.4

1.6

(0.7, 2.5)

(-32, 35)

0.63

(0.60, 0.66)

0.64

Polyunsaturated fat (g)

11.0

4.4

10.7

4.3

0.2

(0.1, 0.4)

(-7, 8)

0.65

(0.62, 0.68)

0.66

Total carbohydrate (g)

179.4

49.9

174.0

50.9

5.4

(3.2, 7.6)

(-77, 87)

0.67

(0.64, 0.70)

0.67

Dietary fiber (g)

19.6

6.2

18.6

5.9

1.0

(0.7, 1.2)

(-9, 11)

0.67

(0.64, 0.70)

0.66

Sugar (g)

22.1

13.4

22.3

13.7

-0.2

(-0.8, 0.4)

(-21, 21)

0.70

(0.67, 0.72)

0.71

Alcohol (g)

2.2

3.2

2.8

3.5

-0.6

(-0.7, -0.5)

(-6, 4)

0.72

(0.69, 0.75)

0.77

Retinol (REd, μg)

1192

490

1142

482

50.3

(29.3, 71.3)

(-742, 843)

0.67

(0.64, 0.70)

0.66

Vitamin D (μg)

12.4

9.0

12.3

8.5

0.1

(-0.3, 0.5)

(-14, 14)

0.69

(0.66, 0.72)

0.70

Vitamin E (mg)

11.0

7.4

11.0

7.4

0.0

(-0.3, 0.3)

(-10, 10)

0.78

(0.76, 0.80)

0.73

Vitamin C (mg)

106

50

96

48

9.6

(7.5, 11.7)

(-69, 88)

0.68

(0.65, 0.70)

0.69

Calcium (mg)

624

246

600

248

23.2

(10.8, 35.6)

(-445, 492)

0.55

(0.51, 0.59)

0.60

% energy from protein

19.2

2.9

19.1

3.0

0.0

(-0.1, 0.2)

(-5, 5)

0.70

(0.67, 0.72)

0.69

% energy from fat

33.5

4.8

33.5

4.8

0.0

(-0.3, 0.2)

(-8, 8)

0.65

(0.62, 0.68)

0.65

% energy from carbohydrate

46.5

5.8

46.3

5.9

0.3

(0.0, 0.6)

(-10, 10)

0.64

(0.61, 0.67)

0.63

% energy from sugar

5.7

3.0

5.8

3.0

-0.2

(-0.3, -0.1)

(-5, 5)

0.68

(0.65, 0.71)

0.68

% energy from alcohol

1.0

1.6

1.4

1.8

-0.3

(-0.4, -0.2)

(-3, 2)

0.74

(0.72, 0.76)

0.78


aSD = Standard deviation, bCI = Confidence interval, cReferred to as limits of agreement in the text, dRetinol equivalents

Parr et al. Nutrition Journal 2006 5:4   doi:10.1186/1475-2891-5-4

Open Data