Table 5.
Validity and reproducibility estimates by semi-quantitative FFQ (SFFQ) for major food contributors to flavonoid intake in Men’s Lifestyle Validation Study and Women’s Lifestyle Validation Study (reference methods: 7-d dietary records (7DDR))
| r s * | 95 % CI | ICC† | |
|---|---|---|---|
| Men | |||
| Apple | 0·78 | 0·70, 0·83 | 0·71 |
| Blueberry | 0·77 | 0·70, 0·82 | 0·72 |
| Grapefruit | 0·79 | 0·71, 0·85 | 0·71 |
| Onion | 0·43 | 0·34, 0·51 | 0·62 |
| Orange | 0·81 | 0·67, 0·90 | 0·39 |
| Orange juice | 0·88 | 0·85, 0·90 | 0·40 |
| Red wine | 0·88 | 0·85, 0·91 | 0·88 |
| Soya milk | 0·89 | 0·84, 0·92 | 0·74 |
| Strawberry | 0·74 | 0·62, 0·83 | 0·63 |
| Tea | 0·71 | 0·66, 0·75 | 0·77 |
| Tofu | 0·54 | 0·45, 0·62 | 0·62 |
| Women | |||
| Apple | 0·63 | 0·54, 0·70 | 0·66 |
| Blueberry | 0·67 | 0·61, 0·73 | 0·70 |
| Grapefruit | 0·77 | 0·59, 0·88 | 0·67 |
| Onion | 0·48 | 0·37, 0·56 | 0·62 |
| Orange | 0·44 | 0·39, 0·48‡ | 0·37 |
| Orange juice | 0·82 | 0·79, 0·85 | 0·38 |
| Soya milk | 0·83 | 0·80, 0·86 | 0·66 |
| Red wine | 0·83 | 0·80, 0·86 | 0·86 |
| Strawberry | 0·67 | 0·52, 0·79 | 0·59 |
| Tea | 0·72 | 0·67, 0·75 | 0·75 |
| Tofu | 0·59 | 0·47, 0·68 | 0·67 |
ICC, rank intraclass correlation coefficient; r s , Spearman’s rank correlation coefficient.
*
Values represent r s comparing the second SFFQ with the average of 2 weeks of weighed 7DDR.
†
Values represent the ICC comparing the first and second SFFQ.
‡
The r s not deattenuated for random measurement error because of high within-person variation in intake (see online supplementary material, Supplemental Table 6).