Nancy G. Sebring|Blakeley I. Denkinger|Carolyn M. Menzie|Lisa B. Yanoff|Shamik Parikh|Jack A. Yanovski
Validation of Three Food Frequency Questionnaires to Assess Dietary Calcium Intake in Adults
objective assess accuracy three selfadministered food frequency questionnaires ffqs measure dietary calcium intake healthy adults design estimates dietary calcium intake one previously validated two recently developed ffqs compared 7day food records subjectssetting healthy adults enrolled outpatient study calcium supplementation completed 36page dietary history questionnaire dhq 3page calcium questionnaire 1page short calcium questionnaire subjects completed 7day food record main outcome measures differences calcium intake reported ffqs calcium intake food records compared statistical analyses spearman correlations used measure associations among variables blandaltman pairwise comparisons conducted assess systematic magnitude biases results studied 341 subjects 745 female mean standard deviation age 3811 years body mass index calculated kgm2 31871 mean standard deviation food record calcium intake 896380 mgday data three ffqs positively related food record calcium intake accounted 40 variance food record dietary calcium intake dhq r2021 calcium questionnaire r2033 short calcium questionnaire r2037 p0001 dhq underestimated daily calcium intake systematic bias 94 mgday p0001 magnitude bias r040 p0001 whereas calcium questionnaire overestimated calcium intake systematic bias 177 mgday p0001 significant magnitude bias r009 p011 short calcium questionnaire showed minimal systematic bias 34 mgday p009 magnitude bias r033 p0001 conclusions three ffqs performed reasonably well estimating dietary calcium intake compared food records may appropriate use select clinical research settings