Estimating children's eating habits. Validity of a questionnaire measuring food frequency compared to a 7-day record.

A questionnaire measuring food frequency was validated against 7-day records of food intake in a group of 30 children, 2-16 years of age. Special emphasis was given to the ability of the questionnaire to estimate frequency of intake of foods of particular interest in diabetes mellitus. Fifteen children had insulin-dependent diabetes; 15 were healthy. Comparison of the two methods regarding frequency of foods with high content of sucrose, protein, fat, fibres, nitrite or vitamin C showed a correlation of 0.52-0.76. The frequency of intake of some staple foods was often overestimated by the questionnaire, while the frequency of meat, sausage and some sweet snacks was underestimated. The use of the questionnaire to identify high or low consumers of the mentioned nutrients showed a rather low sensitivity (0.38-0.50), but a high specificity (0.86-1.0) when compared with results of the 7-day record. In our limited sample of subjects no systematic differences were found comparing sexes or diabetic and healthy children. A food frequency questionnaire may, in spite of some important reservations, be a useful tool for screening purposes when more time-consuming and resource-demanding methods cannot be used.