Validity of a Brazilian food frequency questionnaire against dietary recalls and estimated energy intake

Food frequency questionnaires are commonly used to obtain dietary information in epidemiological studies, but validity studies have primarily been performed in western countries situated in the Northern Hemisphere. A food frequency questionnaire for the Brazilian diet was developed based on a previous survey and expert decision. This questionnaire was compared with four 24-hour recalls among faculty and support staff at the University of Rio de Janeiro, Brazil; and both methods were validated against estimated daily energy requirement. Results of the food frequency questionnaire and the 24-hour recalls were correlated to a similar degree as in studies of other populations. The correlation coefficients varied from 0.55 for calcium to 0.18 for vitamin A, with all but vitamin A being highly significant. The ratio of energy intake to estimated basal metabolism among men was 1.37 for the 24-hour recall and 1.31 for the food frequency; among women the ratio was 1.15 for the 24-hour recall and 1.24 for the food frequency. Women with high predicted energy expenditure often underestimated intake, with a greater discrepancy on the 24-hour recall than the food frequency. (C) 1998 Elsevier Science Inc.