Validation Information: Scottish Collaborative Group FFQ
Hollis 2017
Assessing the relative validity of the Scottish Collaborative Group FFQ for measuring dietary intake in adults
OBJECTIVE: To assess the relative validity of the latest version of the Scottish Collaborative Group (SCG) FFQ (version 6.6) in adults living in Scotland.
DESIGN: A cross-sectional validation study. Participants completed the self-administered, 169-item SCG FFQ followed by a 7d, non-weighed food diary. Energy and energy-adjusted macronutrients and micronutrients were examined for relative validity through Spearman's correlation, the percentage of classification into thirds of intake, Cohen's weighted kappa (κw) and Bland-Altman analysis.
SETTING: General population living in Scotland.
SUBJECTS: Ninety-six adults aged 18-65 years.
RESULTS: Spearman's correlation coefficients ranged from 0·21 (retinol) to 0·71 (Mg). A median of 52% of adults were correctly classified into thirds of intake (range: 42% (PUFA, MUFA and Fe) to 64% (percentage energy from carbohydrates)) and 8% were grossly misclassified into opposite thirds of intake (range: 3% (carbohydrates, percentage energy from carbohydrates) to 19% (thiamin)). Values of κw ranged between 0·20 (PUFA, β-carotene) to 0·55 (percentage energy from carbohydrates). In the Bland-Altman analysis, the smallest limits of agreement, when expressed as a percentage of the mean intake from the FFQ and food diary, were seen for the main macronutrients carbohydrates, fat and protein.
CONCLUSIONS: As in the previous validation study more than 10 years ago, the FFQ gave higher estimates of energy and most nutrients than the food diary, but after adjustment for energy intake the FFQ could be used in place of non-weighed food diaries for most macronutrients and many micronutrients in large-scale epidemiological studies.
Total number of nutrients validated: 26
Not all of the nutrients validated in the validation studies are included in the table below, as statistical data was only selected to be displayed for a number of nutrients, this included:
- Energy
- Fat
- Saturated Fat
- Mono-unsaturated Fat
- Poly-unsaturated Fat
- Carbohydrates
- Protein
- Sugar
- Non‐starch polysaccharides(NSP)
- Sodium
- Calcium
- Iron
- Zinc
- Retinol
- Folate
- Folic Acid
- Vitamin B12
- Vitamin C
- Fruit & Vegetables
- Urinary Nitrogen
To find information on the other validated nutrients please read the validation study.
- Energy
- Macronutrients: 9
- Micronutrients: 16
| Comparator | Lifestage | Sex | Nutrient Measured | Mean Difference | Standard Deviation | Correlation Coefficient | Cohen's Kappa Coefficient | Percentage Agreement | Percentage Agreement Categories | Lower Limits of Agreement | Upper Limits of Agreement |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Estimated Food Diary | Adults | Both | Energy (kJ) | 3005 | 3011 | 0.37 (S) | 0.25 (w) | 45.8 | 3 | -2896 | 8906 |
| Protein (g) | 33# |
16 | 0.47 (S) | 0.37 (w) | 53.1 | 3 | 1 | 64 | |||
| Fat (g) | 27# |
11 | 0.48 (S) | 0.39 (w) | 54.2 | 3 | 6 | 49 | |||
| Saturated Fat (g) | 13# |
7 | 0.52 (S) | 0.39 (w) | 54.2 | 3 | -1 | 27 | |||
| MUFA (g) | 10# |
5 | 0.42 (S) | 0.25 (w) | 41.7 | 3 | 0.2 | 19 | |||
| PUFA (g) | 4# |
4 | 0.35 (S) | 0.20 (w) | 41.7 | 3 | -4 | 13 | |||
| Carbohydrates (g) | 85# |
28 | 0.67 (S) | 0.48 (w) | 57.3 | 3 | 31 | 139 | |||
| Total sugars (g) | 41# |
25 | 0.62 (S) | 0.44 (w) | 55.2 | 3 | -7 | 89 | |||
| Fibre (NSP) (g) | 5# |
6 | 0.59 (S) | 0.46 (w) | 60.4 | 3 | -7 | 17 | |||
| Calcium (mg) | 504.7# |
316.6 | 0.38 (S) | 0.27 (w) | 50.0 | 3 | -115.8 | 1125.2 | |||
| Iron (mg) | 5.6# |
2.6 | 0.42 (S) | 0.23 (w) | 41.7 | 3 | 0.5 | 10.7 | |||
| Zinc (mg) | 4.7# |
2.2 | 0.41 (S) | 0.23 (w) | 43.8 | 3 | 0.4 | 9.0 | |||
| Retinol (µg) | 170.6# |
453.0 | 0.21 (S) | 0.27 (w) | 51.0 | 3 | -717.3 | 1058.5 | |||
| Folate (µg) | 137.3# |
85.8 | 0.48 (S) | 0.34 (w) | 54.2 | 3 | -30.9 | 305.5 | |||
| Vitamin B12 (µg) | 3.8# |
3.2 | 0.45 (S) | 0.30 (w) | 43.8 | 3 | -2.5 | 10.1 | |||
| Vitamin C (mg) | 63.3# |
66.6 | 0.55 (S) | 0.44 (w) | 55.2 | 3 | -67.2 | 193.8 |
Some results have been calculated using statistical techniques based on the published data.
For further information on statistical terms click on Statistical tests used in validation studies
All correlations coefficients in the table are unadjusted unless stated otherwise. For adjusted correlation coefficients and other statistical methods used in the study e.g. paired t-tests, please read the validation articles.
- # Adjusted
- † Energy adjusted.
- ‡ For loge-transformed, energy-adjusted nutrient intakes.
- ^ Adjacent included.
- ᵟ Participants provided identical responses.
- (w) = Weighted.
Hollis JL, Craig LC, Whybrow S, Clark H, Kyle JA, McNeill G. Assessing the relative validity of the Scottish Collaborative Group FFQ for measuring dietary intake in adults. Public health nutrition. 2017 Feb;20(3):449-55.