Skip to main content

Table 4 Relative validity of food groups for the food-frequency questionnaire (n = 21)

From: Reproducibility and relative validity of a newly developed web-based food-frequency questionnaire for assessment of preconception diet

  FFQ 1 WFR Spearman’s r P CC% GM% Kappa k P
Median (P25, P75) Median (P25, P75)
Milk, yoghurt, milk desserts (ml/day) 184 (103, 335) 222 (117, 424) 0.63 0.002 52 0 0.28 0.066
Cheese (g/day) 20 (10, 31) 35 (13, 54) 0.62 0.003 62 5 0.43 0.005
Eggs (g/day) 18 (16, 54) 21 (7.8, 43) 0.72 < 0.001 52 0 0.28 0.061
Poultry (g/day) 22 (11, 54) 23 (3.6, 67) 0.50 0.020 52 14 0.29 0.059
Red meat, non-processed (g/day) 12 (10, 20) 18 (7.4, 32) 0.20 0.392 38 14 0.06 0.689
Red meat, processed (g/day) 14 (1.8, 19) 22 (0, 56) 0.40 0.077 38 5 0.06 0.689
Liver-pate (g/day) 0 (0, 7.1) 0 (0, 6.3) 0.71 < 0.001 71 5 0.50 0.002
Meat dishes (g/day) 45 (23, 66) 0 (0, 0) 0.04 0.873 33 5 < 0.01 1.000
Fatty fish (g/day) 11 (5.4, 21) 0 (0, 17) 0.03 0.891 38 29 0.13 0.301
Lean fish (g/day) 14 (0, 29) 0 (0, 17) 0.10 0.657 19 10 −0.09 0.393
Fish spread (g/day) 7.9 (0, 14) 0 (0, 17) 0.72 < 0.001 67 10 0.49 < 0.001
Fish dishes (g/day) 11 (0, 11) 0 (0, 42) 0.12 0.621 33 19 0.02 0.869
Breakfast cereal, high grain (g/day) 14 (7.1, 107) 22 (2.6, 77) 0.70 < 0.001 57 0 0.36 0.021
Rice, pasta, noodle (g/day) 76 (46, 113) 52 (13, 89) 0.15 0.505 43 19 0.14 0.376
Bread, crispbread, low fibre (g/day) 5.7 (0, 17) 68 (34, 87) 0.59 0.005 43 5 0.15 0.299
Bread, crispbread, high fibre (g/day) 102 (34, 142) 61 (18, 112) 0.58 0.005 43 5 0.13 0.377
Nuts, almonds (g/day) 1.4 (0.7, 7.1) 1.9 (0, 17) 0.53 0.013 62 5 0.43 0.004
Potatoes (g/day) 33 (20, 68) 0 (0, 21) −0.14 0.539 24 38 −0.13 0.371
Vegetables (g/day) 116 (75, 189) 193 (120, 297) 0.70 < 0.001 52 10 0.29 0.060
Fruits (g/day) 172 (50, 249) 117 (74, 279) 0.71 < 0.001 52 0 0.28 0.070
Sugar, sweets, desserts (g/day) 28 (12, 37) 17 (7.4, 41) 0.39 0.081 43 14 0.15 0.339
Oils, butter, margarine (g/day) 2.1 (0.4, 16) 12 (4.7, 22) 0.81 < 0.001 76 0 0.65 < 0.001
Coffee, tea, water (ml/day) 964 (789, 1323) 1383 (771, 1858) 0.56 0.009 52 5 0.29 0.063
Juice, sweet drinks (ml/day) 171 (111, 257) 212 (78, 482) 0.66 0.001 52 0 0.29 0.060
Alcohol (ml/day) 53 (1.4, 154) 0 (0, 120) 0.69 < 0.001 62 5 0.42 0.003
Pizza (g/day) 43 (21, 43) 18 (0, 65) 0.47 0.032 62 19 0.37 0.019
Salty snacks (g/day) 5.7 (2.9, 8.6) 9.1 (1.9, 21) 0.01 0.956 43 33 0.14 0.350
Mixed dishes (g/day) 84 (79, 173) 15 (0, 38) 0.07 0.774 38 19 0.07 0.635
  1. Food intake (gram/milliliter per day) for the food-frequency questionnaire (FFQ) and the 7-day weighed food record (WFR) for food groups (median, 25th and 75th percentile, Spearman’s rank correlation coefficient, percent correctly classified (CC) and grossly misclassified (GM) into tertiles of intake, Cohen’s Kappa value). Statistically significant p-values marked in bold