Table 5.
Spearman correlation coefficients (SCC)1 for the relative validity of short food frequency questionnaire (FFQ)2 compared to blood biomarkers for B-carotene, and vitamins C and E.
| Short FFQ | 8-Day Weighted Diet Record | |||
|---|---|---|---|---|
| Nutrient | Crude | Adjusted | Crude | Adjusted |
| β-carotene | 0.30 | 0.28 | 0.30 | 0.30 |
| Vitamin C | 0.20 | 0.29 | 0.36 | 0.38 |
| Vitamin E | −0.02 | 0.04 | −0.08 | 0.09 |
1 SCC for total nutrient intake including relevant supplement data. 2 The biomarker of β-carotene (µg/day) intake is β-carotene (µmol/L); vitamin C (mg/day) intake is plasma ascorbic acid (µmol/L); and vitamin E (mg/day) intake is serum α-tocopherol (µmol/L).