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Validation Information: Quantitative FFQ (QFFQ)

MacIntyre 2000

A culture-sensitive quantitative food frequency questionnaire used in an African population: 2. Relative validation by 7-day weighed records and biomarkers

Objective: To determine the relative validity of the culture-sensitive quantitative food frequency questionnaire (QFFQ) developed for the Transition, Health and Urbanisation in South Africa (THUSA) study by 7-day weighed food records, urinary nitrogen excretion and basal metabolic rate (BMR).

Design: A cross-sectional study.

Setting: A community-based study in a population stratified according to level of urbanization.

Subjects: Residents of the North West Province, South Africa, aged between 15 and 65 years. The weighed food record study comprised 74 participants while 104 participants collected 24-hour urine samples.

Methods: All participants were interviewed using the QFFQ. For the weighed food record study, participants kept detailed weighed food diaries for seven consecutive days. For the urinary nitrogen study, participants made one 24-hour urine collection. Completeness of the urine collections was checked against 240mg para-aminobenzoic acid. BMR was estimated by the Schofield equations.

Results: Spearman rank correlation coefficients between the QFFQ and weighed food record ranged between 0.14 (fibre) and 0.59 (vitamin C). The QFFQ tended to underestimate intakes compared with the weighed records. Quintile distributions were similar for both methods. The correlation between urinary nitrogen excretion and dietary intake was poor. Possible underreporting was identified for 43% of the participants with the QFFQ and 28% with the weighed food record.

Conclusions: The QFFQ appeared to be a relatively valid instrument for the assessment of dietary intakes of the population of the North West Province. The use of biomarkers in this population was difficult and needs further investigation.

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Validation Information

Author
MacIntyre
Year of Publication
2000

Tool Information

Dietary Exposure Measured
Full Nutrient, Food Groups
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
1 Week
Portion Size Measures info
Not reported
Reporting Method info
Retrospective; Usual
Format info
Paper
Supplements Measured
Not reported
Administration Method info
Not reported

Study Information

Study Location
North West Province, South Africa
Associated Nutrient Database
Food-Finder (South African food composition database)
Comparator Validated Against
Biomarkers, Weighed Food Diary

Participants

Sample Size
74 (Weighed Food Diary), 88 (Biomarkers)
Lifestage
Adolescents, Adults
Age of Population

Range: 15-65 years

Sex
Both
Other Notable Characteristics
Volunteers were recruited from participants in the THUSA study

Total number of nutrients validated: 8 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: 4
  • 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
Weighed Food Diary Adolescents, Adults Both Energy (kcal) 68 805.1 0.31 (S) N/C 32 5 -1495 1632
Energy (kJ) 285 3368.4 0.31 (S) N/C 32 5 -6257 6827
Protein (g) 9.8 28.7 0.30 (S) N/C 31 5
Fat (g) 3.2 33.7 0.25 (S) N/C 36 5
Carbohydrate (g) -3.2 121.3 0.31 (S) N/C 34 5
Fibre (g) 1.1 10.4 0.14 (S) N/C 30 5
Calcium (mg) 51.9 287.3 0.24 (S) N/C 43 5
Iron (mg) 0.5 4.6 0.20 (S) N/C 28 5
Vitamin C (mg) -12.5 70.2 0.60 (S) N/C 66 5
Fruits (g) -59.8
Vegetables (g) -6.3
Biomarkers Adolescents, Adults Both Protein (g) 10 38.8 0.01(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.

MacIntyre U, Venter C, Vorster H. A culture-sensitive quantitative food frequency questionnaire used in an African population: 2. Relative validation by 7-day weighed records and biomarkers. Public health nutrition. 2001;4(1):63-71.