Do aggregates of multiple questions better capture overall fish consumption than summary questions?

Abstract

Objective: To compare intake estimates, validity and reliability of two summary questions to measure fish consumption with information from a detailed semiquantitative food-frequency questionnaire (FFQ) on fish consumption. Design: Population-based, cross-sectional study. Participants completed an FFQ and provided blood samples for erythrocyte membrane eicosapentaenoic acid (EPA) analysis. Aggregate measures of consumption of fresh/frozen/canned fish (fresh fish) and smoked/salted/dried fish (preserved fish) were generated from the FFQ and were compared with responses to the summary questions regarding intakes of similar items. Both methods were tested for validity, using correlation and linear regression techniques with EPA, and retest reliability. Setting: Perth metropolitan area, Western Australia. Subjects: One hundred and nine healthy volunteers of both sexes, aged 21-75 years. Results: The summary fresh fish measure underestimated frequency and grams per week given by the aggregate question by about 50%, while estimates from the summary preserved fish measure were approximately three times that of the aggregate measure. Multiple linear regression analysis suggested that the aggregates accounted for more of the variation in EPA levels, but the difference was minimal. Intra-class correlations confirmed that both methods were reliable. Conclusions: Our study indicates that extensive questioning results in different absolute intakes of fish compared with brief questioning, but does not add any information if ranking individuals according to overall consumption of fish. Keywords Epidemiological methodsFatty acids Omega-3 Questionnaires Reproducibility of results Validation studiesFish consumption has been suggested as a protective factor for the development of various cancers; however, results from studies investigating this association have been inconsistent, ranging from statistically significant associations 1,2 to no clear association at all 3,4 . Possible reasons for this could be either a lack of detail collected by questionnaires used to measure fish consumption and therefore the failure to accurately capture the fish consumption of study participants, or a tendency for investigators to use a single measure to represent overall fish intake in statistical modelling despite having collected detailed information on the various types of fish and seafood consumed. However, there is no published evidence that the distinction among types and styles of fish items is important if ultimately the research question being asked is whether fish, as a food group, has a protective effect on the development of disease.We recently examined data collected as part of a large population-based case-control study for an association between fresh and preserved fish consumption and prostate cancer (Mina K, Fritschi L, Johnson KC, The Canadian Cancer Registries Epidemiology Research Group, 2007, unpublished). Information on fish intake was collected by means of two questions about frequency of consumption of a given am...

Comparison of Seafood Consumption in a Group of Italian Mother-Child Pairs

“…These were expected since it is well-known that, as the number of items increases, overestimation increases as well (23). Moreover, a pilot study conducted by Cavan et al to test a questionnaire on fish consumption already demonstrated that aggregate variables provide higher estimates than summary variables (24), and similar results were found by Mina et al regarding fresh fish (25). …”

Reproducibility of food and nutrient intake estimates using a semi-quantitative FFQ in Australian adults

“…We have also shown that intakes were higher when assessed by FFQ compared with summary questions. It is likely that this represents overestimation of intake by the FFQ items compared with the summary questions, as has been reported in several previous studies (27)(28)(29)(30) . While this may cause problems with estimation of absolute levels of intake, it should not affect the ranking of individuals and thus is not a major problem for studies where this is the primary aim (29) .…”

“…It is likely that this represents overestimation of intake by the FFQ items compared with the summary questions, as has been reported in several previous studies ( 27 – 30 ) . While this may cause problems with estimation of absolute levels of intake, it should not affect the ranking of individuals and thus is not a major problem for studies where this is the primary aim ( 29 ) . Furthermore, this overestimation can potentially be corrected by weighting the itemised FFQ responses by a factor equal to the ratio of the reported frequency on the summary question divided by the estimated frequency from summing the individual items on the FFQ in the same food group ( 28 , 30 ) .…”

The Rural Household Multi-Indicator Survey (RHoMIS) for rapid characterisation of households to inform climate smart agriculture interventions: Description and applications in East Africa and Central America

“…Some of the indicators could be improved upon to give more nuanced interpretations, although there is always tension between speed of survey and detail of results (e.g. Mina et al, 2008;Coates, 2013;De Weerdt et al, 2015). When considering food security and nutrition there is a clear trade-off between the level of detail that can be achieved in quantifying intake of different foodstuffs of individual actors, versus the goal of obtaining a sufficiently accurate picture of the village or local eating…”