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. 2018 Jul 5;20(7):e227. doi: 10.2196/jmir.9113

Table 3.

Relative validity of the FFeQ for nutrients (n=92). Means and cross-classification were computed on crudes variables. All variables were log transformed before computing Pearson correlation coefficients to improve normality.

Nutrients Daily intakes FFeQ2 vs mean of three to six 24-hour recalls

24-hour recalls, median (IQR) FFeQ2, median (IQR) FFeQ2-24-hour recalls, mean (SD) Pearson correlation coefficientsa Cross-classification of nutrient distribution, %

Unadjusted Energy-adjustedb Deattenuatedc Subjects classified in same or adjacent quintile Subjects classified in opposite quintiles
Energy (kcal) 1882.2 (659.6) 1859.5 (819.8) -77.4 (565.3) 0.47 N/Ad 0.50e 66 3
Protein (g) 76.2 (22.6) 72.2 (34.1) -3.5 (23.6) 0.57 0.47 0.52 72 2
Carbohydrates (g) 203.7 (74.6) 202.3 (98.0) -1.3 (72.6) 0.44 0.49 0.54 71 3
Fat (g) 74.2 (28.4) 67.7 (34.8) -3.6 (27.2) 0.47 0.55 0.61 59 3
SFAf (g) 26.9 (13.9) 25.8 (14.2) -2.4g (10.5) 0.61 0.54 0.61 67 1
MUFAh (g) 24.2 (10.4) 26.3 (12.0) 3.1g (12.2) 0.35 0.46 0.53 58 7
PUFAi (g) 8.6 (3.7) 7.8 (3.6) -0.1 (4.5) 0.32 0.48 0.55 58 4
Cholesterol (mg) 244.2 (133.6) 243.3 (130.2) -11.4 (149.9) 0.46 0.31 0.39 65 5
Sugars (g) 79.8 (34.3) 82.5 (46.2) 3.6 (42.9) 0.28 0.39 0.45 71 8
Fiber (g) 21.6 (9.0) 20.9 (9.3) -0.7 (7.9) 0.40 0.52 0.60 64 3
Alcohol (g) 4.7 (14.0) 2.0 (6.9) -3.5g (8.5) 0.77j k k 88 1
Water (g) 2736.5 (868.5) 3182.4 (1744.0) 1310.8g (2654.0) 0.47 0.47 0.51 68 1
Sodium (mg) 2463.5 (1072.0) 2376.7 (945.7) -402.5g (1483.9) 0.37 0.05 0.07 64 1
Magnesium (mg) 319.1 (104.6) 344.0 (194.9) 52.0g (142.4) 0.26 0.25 0.29 62 8
Phosphorus (mg) 1139.6 (334.3) 1114.7 (491.7) 1.6g (352.8) 0.50 0.40 0.45 67 2
Potassium (mg) 3099.1 (1044.0) 3091.6 (1555.0) 133.1 (955.3) 0.49 0.59 0.68 71 2
Calcium (mg) 853.4 (322.5) 1113.7 (625.1) 442.2g (553.1) 0.42 0.38 0.44 70 5
Manganese (mg) 2.8 (1.5) 11.5 (6.5) 9.3g (4.9) 0.08 0.05 0.05 59 8
Iron (mg) 9.4 (4.3) 10.6 (5.0) 1.1g (4.5) 0.28 0.23 0.27 62 3
Copper (mg) 1.4 (0.6) 2.2 (1.5) 0.8g (1.6) 0.08 0.06 0.07 57 7
Zinc (mg) 8.6 (2.9) 9.1 (4.7) 0.4 (5.0) 0.40 0.22 0.26 61 1
Iodine (μg) 120.2 (68.5) 122.1 (57.2) -3.6 (69.1) 0.43 0.24 0.29 68 2
Retinol (μg) 0.0 (0.0) 383.3 (393.4) 506.6g (479.8) 0.11j k k 41 18
Carotene (μg) 3298.9 (2559.0) 3165.6 (2944.0) -306.4 (2833.2) 0.52 0.54 0.68 77 3
Vitamin D (μg) 2.2 (1.5) 2.1 (1.2) -0.4 (1.9) 0.32 0.23 0.31 61 3
Vitamin E (mg) 9.0 (4.3) 10.2 (5.1) 2.1g (5.4) 0.25 0.43 0.53 58 4
Vitamin C (mg) 118.6 (69.7) 124.7 (90.3) 13.3 (68.5) 0.54 0.56 0.68 78 2
Vitamin B1 (mg) 1.1 (0.4) 1.0 (0.4) -0.1g (0.4) 0.31 0.33 0.41 66 4
Vitamin B2 (mg) 1.6 (0.6) 1.5 (0.8) 0.0 (0.6) 0.45 0.48 0.53 68 1
Vitamin B3 (mg) 16.5 (6.8) 15.6 (8.9) 0.0 (6.7) 0.49 0.49 0.58 73 4
Vitamin B5 (mg) 4.8 (2.0) 4.8 (2.4) 0.2 (1.8) 0.47 0.57 0.64 70 1
Vitamin B6 (mg) 1.7 (0.7) 1.6 (0.6) -0.1 (0.7) 0.28 0.38 0.46 58 2
Vitamin B9 (μg) 305.1 (115.1) 321.0 (141.0) 26.9 (126.0) 0.36 0.49 0.58 64 1
Vitamin B12 (μg) 3.3 (2.3) 5.6 (3.8) 2.1g (6.0) 0.31 0.21 0.26 65 7

aThe statistical tests provided P values <.05 for each Pearson correlation coefficient, except for those in italics.

bEnergy adjustment according to the residual method.

cEnergy-adjusted and deattenuated Pearson correlation coefficient (corrected for within-person variation in the three to six 24-hour recalls).

dN/A: not applicable

eUnadjusted and de-attenuated Pearson correlation coefficient.

fSFA: saturated fatty acids.

gThe mean rank of the values of the three to six 24-hr recalls was significantly different to the mean rank of the values of the SFFeQ, according to Wilcoxon signed rank tests. The statistical tests provided P values <.05 for each Pearson correlation coefficient, except for those in italics.

hMUFA: monounsaturated fatty acids.

iPUFA: polyunsaturated fatty acids.

jSpearman correlation coefficients were performed because normality was not respected.

kNormality was not respected. Energy-adjusted and deattenuated coefficients were not performed.