RESEARCH ARTICLE


Validity and Reproducibility of a Semi-Quantitative Food Frequency Questionnaire Adapted to an Israeli Population



Dorit Itzhaki1, Hedy S. Rennert2, Geila S. Rozen3, Gad Rennert*, 2
1 Sub-District Health Office, Akko S.D-Northern District, Ministry of Health, Akko, Israel
2 Department of Community Medicine and Epidemiology, CHS National Cancer Control Center, Carmel Medical Center and Technion Faculty of Medicine, Haifa, Israel
3 Department of Clinical Nutrition, Rambam Medical Center, Haifa, Israel


© 2008 Itzhaki et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the CHS National Cancer Control Center, Carmel Medical Center, 7 Michal St, Haifa 34362, Israel; E-mail:rennert@tx.technion.ac.il


Abstract

Assessment of individual representative dietary practices in epidemiologic research has long been a challenge. Given the differences in eating habits and availability of foods between populations, a study was set to test the reproducibility and validity of an Israeli-adapted semi-quantitative food frequency questionnaire (SFFQ) used in case-control studies of cancer etiology.

Two hundred volunteers between the ages 22-60 were randomly assigned to either complete an SFFQ independently or by nutritionist interview. Participants were then asked to fill out a 3-day food record (FR). SSFQ was repeated 3 months later. Reliability of the repeated SSFQ was examined using Pearson correlations; paired t-tests and Mann-Whitney Rank Test were used to measure reliability and validity of the SFFQ.

Overall, there was >85% agreement ± 1 category between the two encounters in over 75% of the food items. Percent of calories from proteins, fats and carbohydrates were similar for both self-administered and interviewed groups. The majority of correlations between the 1 and 2nd SSFQs for the micronutrients were above 0.75. No differences were noted in percent energy from proteins, fats or carbohydrates between self-administered and interviewer-assisted SSFQ and FR.

The Israeli FFQ was found in our study to be highly reproducible and valid compared to a dietary record.

Keywords: Food frequency questionnaire, reliability, validity, Israel.