Assessing the human intake of heterocyclic amines: Limited loss of information using reduced sets of questions

The aim of this study was to evaluate loss of information from a reduced fo od frequency questionnaire as compared with an extensive reference method d eveloped to assess the intake of heterocyclic amines (HCAs), Food frequency data were linked to concentrations of HCAs in cooked foods to estimate the individual daily exposure to a combination of five HCAs. The number of foo d items in the questionnaire was reduced and selected in three ways: (a) ac cording to the contribution to the estimated total intake; (b) the between- person variance; or (c) dishes included in other studies. The effect on sen sitivity, specificity, concordance, the correlation coefficient, kappa, and simulated relative risks was determined using information from a populatio n-based study conducted in Stockholm. Only a limited amount of misclassific ation was introduced when the number of dishes was reduced from 39 to 15 or 20, and no major difference was seen when dishes were selected according t o the total intake or the between-person variance. Our data indicate that f or a specific exposure, such as HCAs, the loss of accuracy in an analytical epidemiological study is small and may not be relevant when the number of dishes in a food frequency questionnaire is decreased, if the initially cho sen dishes are carefully selected and cover a reasonable part of the total intake or between-person variance.