Development of a quantitative food frequency questionnaire (QFFQ) to assess food, food group, and nutrient intake for the Barbados National Cancer Study (BNCS)

Abstract

Purpose To develop a quantitative food frequency questionnaire (QFFQ) to assess food, nutrient, and food group intake over the previous 12 months, for the Barbados National Cancer Study (BNCS), a comprehensive epidemiologic and genetic study to evaluate environmental (including nutritional intake) and familial factors related to prostate and breast cancer risk in this high-risk population. Methods The Ministry of Health, Barbados, provided a list of all foods reported by 1624 participants in the National Nutrition Survey of 2000, using 24-hour recalls. These foods were listed to provide a 192-item QFFQ. To ensure that the food list was complete and up to date, and to provide data to allow similar foods to be grouped, a random sample was drawn from the national census and eligible residents were asked to complete a 24-hour recall and QFFQ administered by a trained dietitian and research nurse. Food portion sizes were assessed by food models. Results 50 persons (22 men and 28 women with a mean age of 52 and 50 years, respectively) provided a recall and completed the QFFQ (response rate = 79%). All foods reported at least twice in the recalls had been included on the QFFQ, verifying completeness of the food list. Foods that were reported less than six times in the recall or QFFQ were excluded (except alcoholic drinks), and foods that were similar in nutritional composition were combined. The final instrument contained 135 items: breads, cakes, cereals (16 items); rice, pastas, noodles (8); dairy (9); meat, fish, poultry (35); fruit (15); vegetables (23); soft drinks (14); alcoholic beverages (5); and other items (10). Additional questions included supplement use and food preparation methods such as grilling. Conclusion We have developed a QFFQ from a representative population sample which will provide dietary data to examine our hypotheses-on associations between diet and breast and prostate cancer.