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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.

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Validation Information

Author
Hollis
Year of Publication
2017

Tool Information

Dietary Exposure Measured
Full Nutrient, Food Groups
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
2-3 Months
Portion Size Measures info
A ‘measure’ was designed to be a small portion size so that a single standard portion of a food would often be equivalent to 2 measures. A colour photograph additionally accompanied the FFQ.
Reporting Method info
Retrospective; Usual
Format info
Online
Supplements Measured
Not Reported
Administration Method info
Self-administered

Study Information

Study Location
Scotland
Associated Nutrient Database
McCance and Widdowson’s The Composition of Foods, 6th edition
Comparator Validated Against
Food Diary Estimated

Participants

Sample Size
96
Lifestage
Adults
Age of Population

Range: 18-65 years

Mean(SD): 51.4(11.1) years

Sex
Both
Other Notable Characteristics
Participants were recruited from the 2010 Scottish Health Survey (SHeS) sample

Total number of nutrients validated: 26 info

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 info Mean Difference Standard Deviation info Correlation Coefficient info Cohen's Kappa Coefficient Percentage Agreement Percentage Agreement Categories info Lower Limits of Agreement Upper Limits of Agreement
Estimated Food Diary Adults Both Energy (kcal) 718 720 0.37 (S) 0.25 (w) 45.8 3 -692 2129
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.