The reliability of questionnaire-derived historical dietary information and temporal stability of food habits in individuals.

Thirty-four males and 45 females who participated in household surveys 15 or 25 years earlier in rural Denmark were interviewed in 1982 about present and past food habits. Comparison of the information from the survey and the two interviews indicates that recall of past diet is strongly influenced by present dietary habits. As the relative classification of individuals according to their food habits appears to have changed little over time, information on current diet, perhaps supplemented by information on particular changes, can provide useful classification of individuals for epidemiologic purposes.