DIETARY ASSESSMENT IN EPIDEMIOLOGY - COMPARISON OF A FOOD FREQUENCY AND A DIET HISTORY QUESTIONNAIRE WITH A 7-DAY FOOD RECORD

The validity of two types of diet assessment methods, a self-administe red food frequency questionnaire and an interviewer-administered detai led diet history, was assessed relative to a 7-day food record on a po pulation-based sample of 95 men and 108 women in Toronto, Canada, betw een May 1989 and July 1990. Each study subject completed both question naire methods, a food frequency questionnaire and an interviewer-admin istered diet history, as well as a 7-day food record in a crossover de sign. Data were analyzed for both unadjusted and energy-adjusted nutri ents to estimate Pearson's and intraclass correlations and agreement w ithin categories. Mean values for the intake of most nutrients assesse d by the two questionnaire methods were similar. Average, energy-adjus ted Pearson's correlation coefficients for men between a food frequenc y questionnaire and a 7-day food record were 0.55 for macronutrients a nd 0.48 for micronutrients compared with 0.47 for macro- and 0.48 for micronutrients between an interviewer-administered diet history and a 7-day food record. For women, they were 0.48 for macro-and 0.54 for mi cronutrients between a food frequency questionnaire and a 7-day food r ecord and 0.46 and 0.49, respectively, between an interviewer-administ ered diet history and a 7-day food record. The energy-adjusted Pearson correlations were generally higher than were the energy-unadjusted Pe arson correlations and the intraclass correlations. The present study suggests that a food frequency questionnaire is comparable with an int erviewer-administered diet history as a predictor of nutrients as esti mated from a 7-day food record.