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Self-administered semiquantitative food frequency questionnaires: patterns, predictors, and interpretation of omitted items.

ABSTRACT: Food items on a self-administered food frequency questionnaire (FFQ) may be left blank because the food was not consumed, because of difficulties remembering the frequency or amount of intake, or due to an oversight.We explored the predictors and frequency of consumption of omitted food items on an FFQ used in the Nurses' Health Study II. Of 87,676 women who returned a mailed 147-item FFQ in 1999, 34% completed the entire questionnaire, whereas 66% left at least 1 food item blank. Ten or more food items were omitted by 5% of participants. Foods were more likely omitted by women who were older or more physically active. We resurveyed 2876 participants who had left between 1 and 70 food items blank and asked them to fill in the blanks. Overall, 2485 participants provided complete responses.In the resurvey, 64% of the formerly omitted foods were marked as consumed never or less than once per month, 20% as 1 to 3 times per month, 8% as once per week, and 9% as more than once per week. Commonly consumed foods and beverages were less likely omitted because they were not consumed than rarely consumed foods. The best estimate for the true intake value of an omitted food was 0.82 times the average population intake.While calculating nutrient intake, the assumption that items missing represent zero intake is reasonable. However, food items consumed more often in the population at large are less likely than rarely consumed food items to be left blank because they were not consumed.

SUBMITTER: Michels KB

PROVIDER: S-EPMC3935217 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature

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Self-administered semiquantitative food frequency questionnaires: patterns, predictors, and interpretation of omitted items.

Michels Karin B KB Willett Walter C WC

Epidemiology (Cambridge, Mass.) 20090301 2

<h4>Background</h4>Food items on a self-administered food frequency questionnaire (FFQ) may be left blank because the food was not consumed, because of difficulties remembering the frequency or amount of intake, or due to an oversight.<h4>Methods</h4>We explored the predictors and frequency of consumption of omitted food items on an FFQ used in the Nurses' Health Study II. Of 87,676 women who returned a mailed 147-item FFQ in 1999, 34% completed the entire questionnaire, whereas 66% left at leas ...[more]

PMID: 19106799

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Project description:Background:A limited number of studies have evaluated self-reported dietary intakes against objective recovery biomarkers. Objective:The aim was to compare dietary intakes of multiple Automated Self-Administered 24-h recalls (ASA24s), 4-d food records (4DFRs), and food-frequency questionnaires (FFQs) against recovery biomarkers and to estimate the prevalence of under- and overreporting. Design:Over 12 mo, 530 men and 545 women, aged 50-74 y, were asked to complete 6 ASA24s (2011 version), 2 unweighed 4DFRs, 2 FFQs, two 24-h urine collections (biomarkers for protein, potassium, and sodium intakes), and 1 administration of doubly labeled water (biomarker for energy intake). Absolute and density-based energy-adjusted nutrient intakes were calculated. The prevalence of under- and overreporting of self-report against biomarkers was estimated. Results:Ninety-two percent of men and 87% of women completed ?3 ASA24s (mean ASA24s completed: 5.4 and 5.1 for men and women, respectively). Absolute intakes of energy, protein, potassium, and sodium assessed by all self-reported instruments were systematically lower than those from recovery biomarkers, with underreporting greater for energy than for other nutrients. On average, compared with the energy biomarker, intake was underestimated by 15-17% on ASA24s, 18-21% on 4DFRs, and 29-34% on FFQs. Underreporting was more prevalent on FFQs than on ASA24s and 4DFRs and among obese individuals. Mean protein and sodium densities on ASA24s, 4DFRs, and FFQs were similar to biomarker values, but potassium density on FFQs was 26-40% higher, leading to a substantial increase in the prevalence of overreporting compared with absolute potassium intake. Conclusions:Although misreporting is present in all self-report dietary assessment tools, multiple ASA24s and a 4DFR provided the best estimates of absolute dietary intakes for these few nutrients and outperformed FFQs. Energy adjustment improved estimates from FFQs for protein and sodium but not for potassium. The ASA24, which now can be used to collect both recalls and records, is a feasible means to collect dietary data for nutrition research.

Project description:Background:Food frequency questionnaires (FFQs) are used to estimate the usual food and nutrient intakes over a period of time. Such estimates can suffer from measurement errors, either due to bias induced by respondent's answers or to errors induced by the structure of the questionnaire (e.g., using a limited number of food items and an aggregated food database with average portion sizes). The "structural validation" presented in this study aims to isolate and quantify the impact of the inherent structure of a FFQ on the estimation of food and nutrient intakes, independently of respondent's perception of the questionnaire. Methods:A semi-quantitative FFQ (n?=?94 items, including 50 items with questions on portion sizes) and an associated aggregated food composition database (named the item-composition database) were developed, based on the self-reported weekly dietary records of 1918 adults (18-79 years-old) in the French Individual and National Dietary Survey 2 (INCA2), and the French CIQUAL 2013 food-composition database of all the foods (n?=?1342 foods) declared as consumed in the population. Reference intakes of foods ("REF_FOOD") and nutrients ("REF_NUT") were calculated for each adult using the food-composition database and the amounts of foods self-reported in his/her dietary record. Then, answers to the FFQ were simulated for each adult based on his/her self-reported dietary record. "FFQ_FOOD" and "FFQ_NUT" intakes were estimated using the simulated answers and the item-composition database. Measurement errors (in %), spearman correlations and cross-classification were used to compare "REF_FOOD" with "FFQ_FOOD" and "REF_NUT" with "FFQ_NUT". Results:Compared to "REF_NUT," "FFQ_NUT" total quantity and total energy intake were underestimated on average by 198?g/day and 666 kJ/day, respectively. "FFQ_FOOD" intakes were well estimated for starches, underestimated for most of the subgroups, and overestimated for some subgroups, in particular vegetables. Underestimation were mainly due to the use of portion sizes, leading to an underestimation of most of nutrients, except free sugars which were overestimated. Conclusion:The "structural validation" by simulating answers to a FFQ based on a reference dietary survey is innovative and pragmatic and allows quantifying the error induced by the simplification of the method of collection.

Dataset Information

Self-administered semiquantitative food frequency questionnaires: patterns, predictors, and interpretation of omitted items.

Publications

Self-administered semiquantitative food frequency questionnaires: patterns, predictors, and interpretation of omitted items.

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