Validation of a food frequency questionnaire for assessing dietary intake in a study of coronary heart disease risk factors in children.

A food frequency questionnaire (FFQ) was designed and validated for use in an epidemiological survey measuring coronary heart disease risk factors in British children. The questionnaire asked about the frequency of children's consumption of 35 food items over the previous month and was completed by parents/guardians. Food items represented a range of food groups from which children may eat, with emphasis on foods with a high fat and fibre content. The questionnaire was validated against 14 daily recalls of consumption, using the same food list as the FFQ. The sample consisted of 272 children, aged 5-11 years, The response rate for the FFQ was 92% and for the recall, 82% in the first week and 66% in the second week. The level of agreement between the FFQ and the recall was measured by calculating (McGinnis JM & Nestle M, 1989, Am. J. Clin. Nutr. 49, 23-28) the median difference between results from the two methods and (Willett WC (ed.), 1990, Nutritional epidemiology, ch. 15; Oxford University Press) the percentage of children classified by FFQ to within +/- 1 day per week of the recall. Median differences between individual items on the questionnaire and the recall were < or = 0.5 days for 91% of items and equal to 1 day for the remainder. The percentage agreement to within +/- 1 day per week between frequencies reported in the two methods ranged from 99.8% for lamb to 46.8% for low-fibre cereal. Better agreement was found for food items representative of fat intake than those of fibre intake.(ABSTRACT TRUNCATED AT 250 WORDS)