Table 2.
Relative validity of the Food Frequency Questionnaire (FFeQ) for food groups (n=92). For food groups with a proportion of non-consumers >20%, tertiles and quintiles classifications were not performed. Instead, participants were classified as follows: class=1 for null consumption; class=2 for consumption below or equal to the median value in consumers, class=3 for consumption above the median value in consumers.
| Food groups | Daily intakesa | FFeQ2 vs mean three to six 24-hour recalls | |||||
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|
24-hour recalls, median (IQR) | FFeQ2, median (IQR) | FFeQ2-24-hour recalls, mean difference (SD) | Unadjusted Spearman correlation coefficients | Cross-classification of food group distribution, % | ||
|
|
Subjects classified in same tertile | Subjects classified in same or adjacent quintile | Subjects classified in opposite quintiles | ||||
| Whole-grain bread and substitutesb | 18.7 (44.8) | 10.7 (40.0) | -1.2 (54.1) | 0.35 | 53 | —c | — |
| White bread and substitutes | 50.9 (57.7) | 32.0 (69.3) | -2.2 (47.3) | 0.63 | 54 | 78 | 1 |
| Breakfast cerealsb | 0.0 (0.0) | 0.0 (0.5) | 1.9 (9.2) | 0.68 | 79 | — | — |
| Whole-grain pasta, rice and wheatb,d | 0.0 (0.0) | 2.3 (32.0) | 24.2d (46.4) | 0.14e | 49 | — | — |
| White pasta, rice and wheat | 68.3 (82.5) | 45.3 (90.7) | -11.3 (68.2) | 0.52 | 49 | 71 | 1 |
| Legumesb | 0.0 (16.7) | 16.7 (20.0) | 8.8d (30.8) | 0.26 | 27 | — | — |
| French fries and other fried tubersb | 0.0 (15.0) | 8.7 (15.3) | 2.3 (23.8) | 0.35 | 40 | — | — |
| Potatoes and other tubers (not fried)b | 50.0 (64.6) | 40.0 (53.3) | -4.8 (66.9) | 0.26 | 45 | — | — |
| Cooked vegetables | 179.6 (163.0) | 176.7 (166.7) | -8.8 (114.7) | 0.49 | 50 | 68 | 1 |
| Raw vegetables | 63.1 (66.7) | 34.4 (73.7) | -22.1d (51.7) | 0.53 | 58 | 74 | 1 |
| Pizza, lasagna and quicheb | 27.9 (58.6) | 14.2 (15.0) | -23.2d (40.3) | 0.44 | 48 | — | — |
| Sandwich, burgers and kebabb | 0.0 (23.3) | 0.0 (12.0) | -2.6 (18.2) | 0.52 | 61 | — | — |
| Fish fingers/breaded meatb | 0.0 (0.0) | 0.0 (3.3) | -4.1d (14.2) | 0.27 | 64 | — | — |
| Sausages and other processed meatb | 30.0 (30.3) | 11.3 (28.0) | -14.9d (29.5) | 0.38 | 54 | — | — |
| Poultry/rabbitb | 24.2 (47.5) | 20.0 (30.0) | 4.1 (52.8) | 0.45 | 41 | — | — |
| Meat | 43.3 (37.8) | 26.3 (34.7) | -2.3 (44.4) | 0.39 | 38 | 61 | 1 |
| Variety meatsb | 0.0 (0.0) | 0.0 (1.3) | 1.7d (10.0) | 0.09e | 74 | — | — |
| Eggsb | 8.3 (20.0) | 14.1 (21.2) | 6.5d (26.8) | 0.35 | 35 | — | — |
| Fishb | 15.8 (38.8) | 13.3 (20.0) | -3.0 (26.2) | 0.34 | 41 | — | — |
| Seafood (excluding fish)b | 0.0 (2.5) | 0.0 (6.7) | -3.2 (19.1) | 0.33 | 59 | — | — |
| Milkb | 0.0 (63.3) | 0.0 (180.0) | 70.6d (175.2) | 0.73 | 68 | — | — |
| Yogurt, white cheese, cottage cheese | 96.3 (109.8) | 125.0 (123.3) | 28.0d (70.6) | 0.75 | 60 | 88 | 0 |
| Cream dessertb | 0.0 (20.8) | 2.0 (16.7) | 5.1 (36.3) | 0.40 | 53 | — | — |
| Cheese | 31.0 (30.6) | 28.0 (18.0) | -7.1d (25.2) | 0.51 | 52 | 68 | 1 |
| Butter, fresh cream | 4.2 (6.7) | 10.0 (20.0) | 10.1d (20.2) | 0.66 | 51 | 79 | 0 |
| Margarine, mayonnaiseb | 0.0 (0.4) | 0.0 (0.8) | 1.0d (4.4) | 0.60 | 76 | — | — |
| Olive oil | 3.8 (6.3) | 10.0 (14.7) | 6.9d (10.0) | 0.28 | 49 | 62 | 2 |
| Rapeseed oil, walnut oil, mixed oilb | 0.3 (2.0) | 0.7 (2.7) | 0.9d (4.5) | 0.35 | 47 | — | — |
| Sunflower oil, groundnut oilb | 0.0 (0.0) | 0.0 (0.7) | 0.5 (2.8) | 0.21 | 65 | — | — |
| Salty snacksb | 0.0 (8.3) | 4.0 (8.0) | -0.1 (7.5) | 0.41 | 43 | — | — |
| Sweet snacks, chocolate, and Danish pastriesb | 46.7 (50.4) | 13.3 (40.0) | -26.6d (61.0) | 0.26 | 39 | — | — |
| Fruit | 202.8 (220.7) | 351.0 (260.0) | 122.3d (274.7) | 0.67 | 61 | 77 | 1 |
| Water | 992.8 (746.7) | 1550.0 (1200.0) | 1134.5d (2410.6) | 0.52 | 52 | 73 | 1 |
| Coffeeb | 214.2 (303.3) | 200.0 (380.0) | 74.7 (303.4) | 0.81 | 72 | — | — |
| Tea and herb teasb | 135.0 (557.1) | 90.0 (400.0) | -3.1 (310.4) | 0.88 | 71 | — | — |
| Fruit juiceb | 50.0 (143.3) | 50.0 (206.7) | 29.8d (132.6) | 0.61 | 58 | — | — |
| Sweet beveragesb | 0.0 (2.1) | 0.0 (0.0) | -11.5d (50.1) | 0.73 | 79 | — | — |
| Artificially-sweetened beveragesb | 0.0 (0.0) | 0.0 (0.0) | 10.8 (66.7) | 0.55 | 88 | — | — |
| Wineb | 25.0 (90.0) | 11.0 (40.5) | -16.4d (68.7) | 0.81 | 67 | — | — |
| Alcoholic beverages excluding wineb | 13.3 (52.5) | 2.5 (20.0) | -24.3d (65.5) | 0.48 | 54 | — | — |
aMeasured in grams (food) or milliliters (beverages).
bThese food groups have a large proportion of non-consumers (>20%).
cDashes indicate food groups that have a large proportion of nonconsumers (>20%). Classification into quintiles of consumption was not performed.
dThe mean rank of the values of the three to six 24-hour recalls was significantly different to the mean rank of the values of the SFFeQ, according to Wilcoxon signed rank tests.
eUnadjusted Spearman correlation coefficients for which the statistical tests did not provide P values <.05.