Background
Methods
i. Dietary intakes
Study population
Dietary measurements - repeated 24-hour recalls
Expanded food frequency questionnaire
(ii). Biomarkers of cholesterol and folate - calibration study
Study population
Sample collection and biochemical analyses
(iii) Other measurements
Exclusions
Statistical analyses
Results
Samples | |||
---|---|---|---|
Dietary intakes | Biomarker a
| ||
Males | Females | ||
n
| 31 | 39 | 176 |
Age (years): mean ± sd | 40.9 ± 16.5 | 41.5 ± 16.8 | 61.6 ± 10.5†
|
Weight (kg): mean ± sd | 77.9 ± 13.4 | 77.5 ± 20.6 | 74.8 ± 14.1 |
Height (m): mean ± sd | 172.7 ± 6.6 | 161.6 ± 7.8** | 171.6 ± 7.2 |
Body mass index (kg/m2) | 26.1 ± 4.0 | 29.7 ± 8.1* | 25.3 ± 4.4 |
Obesity (BMI≥30.0 kg/m2) (%) | 14.3 | 34.2 | 14.8 |
Relative Validity - dietary intakes
24-hour recalls vsFFQ 1†
| 24-hour recalls vs. FFQ 2†
| ||||||
---|---|---|---|---|---|---|---|
Repeat 24- hour recalls | FFQ 1 | FFQ 2 | Unadjusted | Energy adjusted | Unadjusted | Energy adjusted | |
r
|
r
|
r
|
r
| ||||
Total Energy (kcal) | 2324 ± 662 | 2541 ± 559* | 2434 ± 644* | 0.41 | 0.45 | ||
Total Carbohydrate (g) | 327.9 ± 105.8 | 361.1 ± 105.9* | 340.3 ± 113.2* | 0.37 | 0.35 | 0.38 | 0.38 |
Protein (g) | 101.7 ± 29.9 | 91.4 ± 27.5 | 103.1 ± 36.5 | 0.26 | 0.25* | 0.33 | 0.31 |
Total Fat (g) | 66.2 ± 22.8 | 64.8 ± 23.1 | 63.5 ± 32.8* | 0.38 | 0.41 | 0.37 | 0.40 |
Total Saturated Fat (g) | 29.9 ± 11.9 | 25.5 ± 10.4 | 28.6 ± 11.8 | 0.45 | 0.48 | 0.42 | 0.43 |
Total MUFA (g) | 19.8 ± 10.7 | 19.3 ± 8.5 | 21.9 ± 12.6* | 0.51 | 0.59 | 0.40 | 0.46 |
Total PUFA (g) | 12.5 ± 5.1 | 11.8 ± 4.4 | 13.3 ± 6.3* | 0.33 | 0.29 | 0.36 | 0.38 |
Linoleic acid | 15.7 ± 12.4 | 16.7 ± 14.2 | 16.1 ± 14.1 | 0.43 | 0.41 | 0.47 | 0.44 |
Linolenic acid | 0.69 ± 0.2 | 0.81 ± 0.3* | 0.73 ± 0.3* | 0.22‡
| 0.35 | 0.38 | 0.43 |
Cholesterol (mg) | 268.1 ± 106.1 | 259.7 ± 117.2 | 251.2 ± 114.0 | 0.52 | 0.53 | 0.47 | 0.41 |
Calcium (mg) | 727 ± 218 | 782 ± 281 | 783 ± 341 | 0.44 | 0.50 | 0.45 | 0.45 |
Iron (g) | 21.7 ± 9.3 | 20.0 ± 5.9 | 22.1 ± 9.8 | 0.43 | 0.42 | 0.44 | 0.43 |
Retinol (ug) | 2171 ± 1680 | 2201 ± 1405 | 1860 ± 1143 | 0.21‡
| 0.22 | 0.18‡
| 0.17‡
|
Beta-carotene (mg) | 2271 ± 2420 | 2410 ± 2680* | 1983 ± 2256** | 0.35 | 0.33 | 0.34 | 0.34 |
Vitamin E (mg) | 19.7 ± 7.5 | 15.4 ± 7.8** | 16.8 ± 6.1** | 0.21‡
| 0.20‡
| 0.23 | 0.23 |
Folate (g) | 625.7 ± 242 | 634 ± 233 | 590 ± 185 | 0.56 | 0.59 | 0.42 | 0.45 |
Total dietary fiber (g) | 28.6 ± 11.7 | 33.7 ± 11.8 | 30.7 ± 11.7 | 0.38 | 0.44 | 0.43 | 0.50 |
Alcohol (g) | 2.8 ± 5.4 | 2.4 ± 2.7 | 2.6 ± 9.1 | 0.75 | 0.79 | 0.85 | 0.86 |
Proportion (%) of subjects classified FFQ 1* | |||
---|---|---|---|
Agreement in same quartile | Misclassification in opposite quartile | Kappa (K w) | |
Total Energy (kcal) | 48.5 | 10.0 | 0.40 |
Total Carbohydrate (g) | 40.0 | 8.6 | 0.33 |
Protein (g) | 32.8 | 24.3 | 0.17 |
Total Fat (g) | 42.8 | 11.4 | 0.35 |
Total Saturated Fat | 45.5 | 8.6 | 0.38 |
Total MUFA | 41.4 | 7.1 | 0.42 |
Total PUFA | 40.0 | 10.0 | 0.31 |
Linoleic | 42.8 | 11.4 | 0.34 |
Linolenic | 34.3 | 11.4 | 0.22 |
Cholesterol (mg) | 47.1 | 7.1 | 0.43 |
Calcium (mg) | 57.1 | 8.6 | 0.51 |
Iron (g) | 51.4 | 10.0 | 0.48 |
Retinol (ug) | 28.6 | 20.0 | 0.13 |
Beta-carotene (mg) | 44.2 | 14.2 | 0.23 |
Vitamin E (mg) | 32.8 | 23.8 | 0.15 |
Folate (g) | 58.6 | 4.3 | 0.57 |
Total dietary fiber (g) | 44.2 | 4.3 | 0.42 |
Alcohol | 70.0 | 4.3 | 0.64 |
Repeat 24- hour recalls Median | FFQ 1 Median | FFQ 2 Median | Spearman's r24-hr recalls vs. FFQ 1 | Spearman's r24-hr recalls vs. FFQ 2 | |
---|---|---|---|---|---|
Cereals (g) | 469.7 | 492.4 | 487.0 ab.
| 0.39 | 0.42 |
Poultry (g) | 48.1 | 36.6 | 55.1 ab
| 0.30 | 0.37 |
Red meat (g) | 16.9 | 14.1 | 15.2 | 0.55 | 0.61 |
Fish (g) | 29.5 | 23.5 | 27.7 | 0.38 | 0.53 |
Eggs (g) | 7.4 | 6.7 | 6.4 | 0.56 | 0.54 |
Fruits (g) | 394.4 | 430.0 | 373.3 ab
| 0.27 | 0.30 |
Dark green leafy and yellow vegetables (g) | 85.8 | 89.0 | 97.9 b
| 0.53 | 0.45 |
Other vegetables (g) | 50.1 | 57.1 | 56.5 | 0.46 | 0.45 |
Peas and beans (g) | 19.4 | 21.5 | 22.4 | 0.44 | 0.39 |
Calibration - biomarkers
Levels in quartiles on the basis of FFQ |
p
trend
| Correlation of biomarker with dietary intakea
| |||||
---|---|---|---|---|---|---|---|
Q1 | Q2 | Q3 | Q4 | unadjusted r
| adjusted b r
| ||
Cholesterol | |||||||
Intake from FFQ (mg) | 95.3 ± 38.9 | 179.4 ± 19.9 | 267.5 ± 30.9 | 468.9 ± 113.8 | < 0.0001 | ||
Serum cholesterol (μmol/l) | 4.46 ± 1.04 | 4.63 ± 0.96 | 4.69 ± 1.09 | 4.93 ± 1.07 | 0.020 | 0.19 | 0.24 |
Folate | |||||||
Intake from FFQ (μg) | 427 ± 102 | 643 ± 52 | 845 ± 63 | 1123 ± 138 | < 0.0001 | ||
Whole blood folate (ng/ml) | 92.8 ± 132.1 | 108.0 ± 120.2 | 63.5 ± 33.4 | 94.9 ± 148.7 | 0.628 | 0.11 ns
| 0.33 |
Serum folate (ng/ml) | 9.55 ± 5.05 | 10.95 ± 3.95 | 11.15 ± 3.74 | 12.85 ± 5.84 | 0.009 | 0.22 | 0.25 |
Reproducibility
FFQ 1 vs. FFQ 2 | ||
---|---|---|
Unadjusted
r(CI) | Energy adjusted
r(CI) | |
Total Energy (kcal) | 0.87 (0.78, 0.92) | |
Total Carbohydrate | 0.85 (0.76, 0.91) | 0.76 (0.61, 0.85) |
Protein | 0.83 (0.73, 0.90) | 0.79 (0.66, 0.87) |
Total Fat | 0.85 (0.75, 0.90) | 0.74 (0.57, 0.84) |
Total Saturated Fat | 0.78 (0.65, 0.87) | 0.50 (0.18, 0.69) |
Total MUFA | 0.82 (0.71, 0.89) | 0.79 (0.66, 0.87) |
Total PUFA | 0.75 (0.60, 0.80) | 0.54 (0.24, 0.71) |
Linoleic acid | 0.75 (0.59, 0.85) | 0.68 (0.48, 0.80) |
Linolenic acid | 0.73 (0.55, 0.83) | 0.55 (0.26, 0.72) |
Cholesterol | 0.80 (0.67, 0.87) | 0.80 (0.67, 0.87) |
Calcium | 0.85 (0.75, 0.91) | 0.79 (0.66, 0.87) |
Iron | 0.90 (0.84, 0.94) | 0.68 (0.47, 0.80) |
Retinol | 0.73 (0.56, 0.83) | 0.74 (0.57, 0.84) |
Beta-carotene (ug) | 0.71 (0.53, 0.82) | 0.75 (0.59, 0.85) |
Vitamin E | 0.77 (0.56, 0.82) | 0.78 (0.58, 0.85) |
Folate | 0.88 (0.80, 0.92) | 0.77 (0.62, 0.86) |
Vitamin K | 0.72 (0.54, 0.83) | 0.72 (0.54, 0.83) |
Zinc | 0.79 (0.65, 0.87) | 0.79 (0.66, 0.87) |
Total dietary fiber | 0.82 (0.70, 0.90) | 0.84 (0.68, 0.90) |
Alcohol | 0.76 (0.45, 0.89) | 0.68 (0.27, 0.86) |