Development of a semi-quantitative Food Frequency Questionnaire (FFQ) to assess dietary intake of multiethnic populations

The Food Frequency Questionnaire (FFQ) is one of the most commonly used methods in epidemiological studies to assess long-term nutritional exposure. The purpose of this study is to develop a general FFQ for the Israeli population and present the procedures undertaken to select foods to be included in a questionnaire for a multiethnic population. Random population cluster sampling was done using voter registration lists of the Negev Jewish population, aged 35 years and over, which were divided into three groups based on where they were born, namely: Israel, Asia-Africa and Europe-America. Participants were interviewed for their dietary intake using 24 hour recalls. Foods eaten by our subjects were aggregated into conceptually similar food groups and entered in stepwise regression models to predict variation in nutrient intake. Separate models were created for each origin group. It was found that the dietary intake was significantly lower for energy and vitamin E among European-American born subjects and significantly lower for calcium intake among Asian-African born subjects. Differences between ethnic groups were seen in the list of foods, which explained the between-person variability for energy and zinc. For most nutrients, fewer items were needed to explain the between-person variation in the group of people born in Israel. The final list of foods included 126 items and explained over 90% of the between-person variability in selected nutrients for all three groups. The newly developed FFQ for the Negev population includes 126 items that are sufficient to rank the nutritional exposure of people over 35 years old from the three origin groups in Israel.