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Table 3 Pooled effect estimates and heterogeneity of the correlation coefficients for the reproducibility of FFQ for micronutrient*

From: A meta-analysis of the reproducibility of food frequency questionnaires in nutritional epidemiological studies

Nutrient ICC SCC
Crude Energy-adjusted Crude Energy-adjusted
N ICC (95% CI) I2 N ICC (95% CI) I2 N ICC (95% CI) I2 N ICC (95% CI) I2
Vitamin A 27 0.623 (0.544, 0.692) 95.2 12 0.597 (0.464, 0.705) 92.2 42 0.613 (0.570, 0.651) 87.2 22 0.553 (0.470, 0.627) 89.8
Retinol 18 0.589 (0.513, 0.656) 85.3 9 0.537 (0.421, 0.635) 74 49 0.573 (0.537, 0.607) 80.6 38 0.513 (0.460, 0.562) 84.3
Carotene 9 0.632 (0.499, 0.735) 97.1 5 0.512 (0.328, 0.658) 0.86 25 0.605 (0.558, 0.649) 89 21 0.510 (0.427, 0.584) 90.8
β-Carotene 21 0.677 (0.630, 0.719) 76.1 6 0.613 (0.456, 0.733) 81.9 39 0.613 (0.573, 0.649) 72.3 28 0.554 (0.513, 0.593) 56.5
Vitamin C 47 0.665 (0.600, 0.722) 96.1 22 0.635 (0.526, 0.723) 94.9 92 0.623 (0.594, 0.650) 85.3 57 0.596 (0.555, 0.633) 83.6
Vitamin D 16 0.678 (0.546, 0.777) 98.4 5 0.671 (0.391, 0.837) 98.1 30 0.617 (0.572, 0.659) 83.5 15 0.560 (0.475, 0.635) 81.5
Vitamin E 34 0.665 (0.576, 0.738) 97.5 15 0.606 (0.484, 0.704) 94.4 52 0.626 (0.583, 0.667) 91.4 30 0.555 (0.490, 0.613) 87
Vitamin K 3 0.656 (0.430, 0.804) 97.4 2 0.693 (0.652, 0.729) 0 7 0.602 (0.511, 0.679) 60.4 5 0.658 (0.553, 0.742) 32.7
Thiamin 31 0.630 (0.587, 0.670) 87.3 12 0.606 (0.492, 0.699) 93.1 55 0.606 (0.579, 0.633) 74.3 39 0.522 (0.475, 0.566) 79.5
Riboflavin 28 0.667 (0.616, 0.712) 91.7 10 0.619 (0.483, 0.726) 94.7 54 0.640 (0.611, 0.667) 81 35 0.581 (0.528, 0.628) 85.4
Niacin 22 0.667 (0.609, 0.718) 89.4 10 0.605 (0.499, 0.693) 90.7 39 0.643 (0.573, 0.704) 94.3 34 0.517 (0.452, 0.576) 86.2
Vitamin B6 13 0.723 (0.522, 0.847) 98.4 5 0.712 (0.516, 0.838) 96.6 27 0.610 (0.553, 0.662) 78.8 19 0.555 (0.483, 0.619) 77.2
Folate 25 0.637 (0.582, 0.686) 90.5 6 0.597 (0.495, 0.684) 76.4 49 0.612 (0.577, 0.646) 81.6 26 0.605 (0.544, 0.659) 82.5
Vitamin B12 13 0.678 (0.507, 0.797) 97.7 7 0.683 (0.496, 0.809) 96.8 28 0.635 (0.577, 0.686) 82.3 21 0.575 (0.490, 0.648) 87.5
Se 11 0.661 (0.608, 0.709) 69.3 4 0.586 (0.429, 0.709) 78.7 15 0.648 (0.586, 0.702) 82.4 11 0.568 (0.446, 0.670) 87.6
Mg 19 0.674 (0.612, 0.728) 88.4 6 0.617 (0.492, 0.717) 87.5 30 0.669 (0.603, 0.725) 89.9 19 0.629 (0.544, 0.701) 86.8
Ca 52 0.635 (0.588, 0.676) 91.8 23 0.642 (0.566, 0.708) 91 87 0.622 (0.594, 0.649) 83 55 0.586 (0.545, 0.626) 84.1
Fe 39 0.640 (0.581, 0.692) 93.9 19 0.564 (0.496, 0.625) 79.4 75 0.613 (0.582, 0.642) 83.8 47 0.570 (0.525, 0.612) 82.8
I 2 0.499 (0.338, 0.632) 73.7 3 0.507 (0.421, 0.585) 35 2 0.828 (0.724, 0.894) 19.8 1 0.744 (0.600, 0.841) N/A
Zn 26 0.595 (0.556, 0.631) 68.8 12 0.573 (0.495, 0.641) 72.3 26 0.623 (0.565, 0.675) 85.3 18 0.597 (0.507, 0.675) 86.7
Cu 4 0.658 (0.620, 0.693) 0 1 0.690 (0.646, 0.728) N/A 6 0.748 (0.620, 0.837) 86.6 5 0.726 (0.608, 0.813) 86.6
K 25 0.672 (0.598, 0.736) 95.4 7 0.637 (0.486, 0.752) 93.6 49 0.637 (0.605, 0.667) 80 34 0.608 (0.566, 0.647) 73.4
P 23 0.605 (0.521, 0.676) 91.9 9 0.635 (0.544, 0.711) 80.7 43 0.621 (0.575, 0.662) 83.4 30 0.579 (0.521, 0.630) 82.1
Na 25 0.652 (0.499, 0.766) 98.2 8 0.670 (0.474, 0.802) 97 41 0.623 (0.582, 0.661) 83.9 30 0.552 (0.489, 0.609) 86.7
Mn 2 0.621 (0.382, 0.781) 64.8 N/A N/A N/A 5 0.655 (0.596, 0.707) 0 2 0.719 (0.645, 0.779) 0
  1. aCI confidence interval, I2 inconsistency index, N/A not available