Determinants of long-term (24-year) diet recall ability using a 21-item food frequency questionnaire.

This study sought to determine how well individuals are able to recall accurately their food habits of 24 years ago and identify those factors that are predictive of recall ability. We investigated the self-reported dietary intakes of 216 people, one-half of whom were vegetarians, including cancer cases and controls. We compared 21 key food items reported in 1960 with the same data reported in 1984. Recall ability was the highest for persons with stable diets. Vegetarian status, education, and church attendance were the other significant determinants of exact recall; age and church attendances were the only significant determinants of recall error. After excluding nonusers of particular foods, we found a positive correlation between frequency of use and recall ability.