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Validation Information: FFQ (short NDNS)

Shaw 2021

Development of a short food frequency questionnaire to assess diet quality in UK adolescents using the National Diet and Nutrition Survey

Background UK adolescents consume fewer fruits and vegetables and more free sugars than any other age group. Established techniques to understand diet quality can be difficult to use with adolescents because of high participant burden. This study aimed to identify key foods that indicate variation in diet quality in UK adolescents for inclusion in a short food frequency questionnaire (FFQ) and to investigate the associations between adolescent diet quality, nutritional biomarkers and socio-demographic factors.

Methods Dietary, demographic and biomarker data from waves 1–8 of the National Diet and Nutrition Survey rolling programme were used (n=2587; aged 11–18 years; 50% boys; n=≤997 biomarker data). Principal component analysis (PCA) was applied to 139 food groups to identify the key patterns within the data. Two diet quality scores, a 139-group and 20-group, were calculated using the PCA coefficients for each food group and multiplying by their standardised reported frequency of consumption and then summing across foods. The foods with the 10 strongest positive and 10 strongest negative coefficients from the PCA results were used for the 20-group score. Scores were standardised to have a zero mean and standard deviation of one.

Results The first PCA component explained 3.0% of variance in the dietary data and described a dietary pattern broadly aligned with UK dietary recommendations. A correlation of 0.87 was observed between the 139-group and 20-group scores. Bland-Altman mean difference was 0.00 and 95% limits of agreement were − 0.98 to 0.98 SDs. Correlations, in the expected direction, were seen between each nutritional biomarker and both scores; results attenuated slightly for the 20-group score compared to the 139-group score. Better diet quality was observed among girls, non-white populations and in those from higher socio-economic backgrounds for both scores.

ConclusionsThe diet quality score based on 20 food groups showed reasonable agreement with the 139-group score. Both scores were correlated with nutritional biomarkers. A short 20-item FFQ can provide a meaningful and easy-to-implement tool to assess diet quality in large scale observational and intervention studies with adolescents.

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
4 Days
Portion Size Measures info
This score has no units. Subtract the mean and divide by the SD of the score in the dataset to get a score with internal standard deviation units. See paper additional table 2.
Reporting Method info
Usual; Retrospective
Format info
Supplements Measured
Not Reported
Administration Method info

Study Information

Study Location
Associated Nutrient Database
Comparator Validated Against


Sample Size
Age of Population

Range:111-18 years

Other Notable Characteristics
The tool was developed from 4d food diaries from NDNS and compared against NDNS biomarkers

Total number of nutrients validated: 7 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.

  • Macronutrients: 0
  • Micronutrients: 7
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
Biomarkers Adolescents Both Urinary sodium (mmol/L) -0.14 (S)
Serum folate (nmol/L) 0.42(S)
Vitamin B12 (pmol/l) 0.21 (S)
Vitamin C (mg) 0.3 (S)

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.

Shaw, S., Crozier, S., Strömmer, S. et al. Development of a short food frequency questionnaire to assess diet quality in UK adolescents using the National Diet and Nutrition Survey. Nutr J 20, 5 (2021).