Table 5.
FFQ reproducibility: Intraclass correlation coefficients, weighted kappa and same and adjacent % agreement for comparison of FFQ-1 and FFQ-2 (n = 107).
| Nutrients | FFQ-1 | FFQ-2 | FFQ-1 vs. FFQ-2 | ||
|---|---|---|---|---|---|
| Mean ± SD | Mean ± SD | ICC # | Weighted Kappa | Same and Adjacent % Agreement | |
| Energy (kcal) | 3061.8 ± 1479.4 | 2538.5 ± 1066.5 | 0.85 ** | 0.56 | 95.3 |
| Protein (g) | 112.2 ± 59.8 | 93.5 ± 51.8 | 0.44 * | 0.56 | 92.5 |
| Carbohydrate(g) | 345.6 ± 178.0 | 280.4 ± 132.9 | 0.56 ** | 0.51 | 90.7 |
| Fiber, Total(g) | 27.4 ± 12.9 | 23.6 ± 11.0 | 0.64 ** | 0.50 | 85.1 |
| Fat, Total(g) | 134.1 ± 67.4 | 113.2 ± 52.1 | 0.67 ** | 0.49 | 89.7 |
| Cholesterol(mg) | 345.4 ± 298.7 | 305.1 ± 363.5 | 0.55 ** | 0.46 | 85.1 |
| α-Tocopherol(mg) | 16.0 ± 8.6 | 14.3 ± 7.4 | 0.56 ** | 0.39 | 86.0 |
| Vitamin A (RAE) | 694.1 ± 786.9 | 564.8 ± 670.6 | 0.44 ** | 0.40 | 85.1 |
| α-carotene(μg) | 93.0 ± 60.7 | 77.3 ± 47.3 | 0.62 ** | 0.36 | 82.2 |
| β-carotene(μg) | 2328.4 ± 1333.4 | 1963.5 ± 1221.5 | 0.58 ** | 0.36 | 84.1 |
| Lutein+Zeaxanthin | 2116.1 ± 1762.7 | 1703.9 ± 1469.3 | 0.36 * | 0.25 | 74.8 |
| β-cryptoxanthin | 210.8 ± 157.2 | 151.0 ± 127.6 | 0.70 ** | 0.38 | 80.4 |
| Lycopene | 3180.3 ± 3151.1 | 2194.3 ± 1287.8 | 0.63 ** | 0.32 | 82.2 |
| Total Carotenoids | 7861.0 ± 5135.3 | 6068.8 ± 3554.2 | 0.53 ** | 0.33 | 80.1 |
ICC: Intraclass correlation coefficients; SD: Standard Deviation; FFQ-1: 1st food frequency questionnaire collected (baseline); FFQ-2: 2nd food frequency questionnaire collected (one year after baseline). # ICCs are derived from log-transformed values that are energy-adjusted except for energy. * p-value < 0.05; ** p-value < 0.01.