Simulated validation of a brief food frequency questionnaire

Area of Science:

• Nutritional Epidemiology
• Dietary Assessment Methods

Background:

• Food Frequency Questionnaires (FFQs) are crucial for large-scale dietary assessment.
• Validating brief FFQs is essential for efficient nutrient intake estimation in cohort studies.

Purpose of the Study:

• To simulate and validate a brief 45-item FFQ against a more extensive 131-item semiquantitative FFQ.
• To assess the reliability of the brief FFQ for estimating daily nutrient intakes.

Main Methods:

• Simulated a brief FFQ by reducing items and categories from the Health Professionals Follow-up Study's extensive FFQ.
• Calculated nutrient intakes for 127 men using the simulated brief FFQ and compared them to two 1-week diet records.
• Computed deattenuated correlation coefficients for 25 energy-adjusted nutrients.

Main Results:

• Correlation coefficients for nutrient values ranged from 0.12 (iron) to 0.76 (vitamin C), with a mean of 0.26.
• The brief FFQ demonstrated reasonable effectiveness for assessing intakes of total fat, saturated fat, monounsaturated fat, carbohydrate, dietary fiber, carotene, vitamin C, calcium, potassium, and magnesium.
• Increasing frequency categories modestly improved correlations, while using regression coefficients decreased them.

Conclusions:

• The brief 45-item FFQ is a reasonably effective tool for assessing relative dietary intakes of several key nutrients.
• This validated brief FFQ can be a valuable instrument for nutritional epidemiology and public health research.
• Further refinement of frequency categories may enhance the accuracy of nutrient assessment.