Wayne Smith|Paul Mitchell|Elizabeth M. Reay|Karen Webb|Philip W. Harvey
Validity and reproducibility of a self-administered food frequency questionnaire in older people
Australian National University|Westmead Hospital|University of Sydney|University of Sydney|University of Sydney|Australian Institute of Tropical Health and Medicine|University of Queensland
study assesses validity reproducibility 145item selfadministered food frequency questionnaire ffq representative older population aged 63 80 semiquantitative ffqs completed 89 3654 residents attending communitybased eye study sydney australia ffqs validity assessed three fourday weighed food records wfrs completed four months apart 79 people 152 subjects completed repeat ffq year baseline ffq 131 completed second repeat ffq six weeks later short longterm reproducibility ffq assessed using data subjects comparison ffq average three fourday weighed food records resulted energyadjusted spearman correlations 05 nutrients proportion subjects correctly classified within one quintile category nutrient intake ranged 57 zinc 82 vitamin c nutrients correctly classified within one quintile 70 subjects quadratic weighted kappas reasonable 03 05 nutrients ffq highly reproducible short term correlations nutrients 070 080 acceptably reproducible longer term correlations mostly 060 070 results verify possible use relatively simple comprehensive selfadministered ffqs study nutrient exposures largescale epidemiological studies elderly expect reasonably high ffq response rates