Log in Register

Tool Library Tool Information Best Practice Guidelines – Evaluation Checklist (opens new tab)

Validation Information: Scottish Collaborative Group FFQ

Heald 2006

Phyto-oestrogen intake in Scottish men: use of serum to validate a self-administered food frequency questionnaire in older men

OBJECTIVE: To study dietary intake and serum concentrations of isoflavones in order to provide relative validation of isoflavone intake estimates from the Scottish Collaborative Group - Food-Frequency Questionnaire (SCG-FFQ).

DESIGN: Validation study.

SETTING: Southern Scotland.

METHOD: Dietary intake of isoflavones was estimated using the semiquantitative SCG-FFQ and rank correlation and Kappa statistics were used for the relative validation of intakes against serum isoflavone concentrations in 203 male participants who were population controls in a case-control study of diet and prostate cancer.

RESULTS: The median intake of isoflavones (daidzein and genistein) was 1.0mg/day; (l-QR 0.6-1.8). The median serum concentration of genistein was 33.79 nmol/l (I-QR 14.12-64.93), nearly twice that of daidzein (18.00 nmol/l, I-QR 8.26-29.45). Equol was detected in 49% of subjects; in these subjects the median was 0.67 nmol/l (I-QR 0.34-1.51). Isoflavone intake was significantly correlated with serum concentrations of daidzein (p = 0.24, P = 0.001), genistein (p = 0.26, P < 0.001) and total isoflavonoids (sum of daidzein, genistein and equol) (p = 0.27, P < 0.001). Whereas values for weighted Kappa ranged from 0.16 (P = 0.002) for daidzein and equol combined to 0.22 (P < 0.001) for genistein.

CONCLUSIONS: These results demonstrate the suitability of the SCG-FFQ to rank usual isoflavone intakes in older Scottish men, a population observed to have low consumption of soy foods.

Web Link

Validation Information

Year of Publication

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
Supplements Measured
Administration Method info

Study Information

Study Location
Glasgow, Scotland
Associated Nutrient Database
McCance and Widdowson’s The Compostition of Foods (5th edition) and related supplements
Comparator Validated Against


Sample Size
Adults, Elderly
Age of Population

Range: 51-75 years

Mean: 67 years

Male Only
Other Notable Characteristics
Control participants in the PCANDIET study

Total number of nutrients validated: 5 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: 0
  • Micronutrients: 4
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 Adults, Elderly Male Only

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.

Heald CL, Bolton-Smith C, Ritchie MR, Morton MS, Alexander FE. Phyto-oestrogen intake in Scottish men: use of serum to validate a self-administered food-frequency questionnaire in older men. European journal of clinical nutrition. 2006 Jan 1;60(1):129-35.