Reproducibility and Validity of a Food Frequency Questionnaire for Assessing Dietary Consumption via the Dietary Pattern Method in a Chinese Rural Population.

Xudong Liu,Qingkun Song,Ignatius Tak-Sun Yu,Sihao Lin,Xiangqian Lao,Xiaorong Wang,Chung-Jung Chiu

doi:10.1371/journal.pone.0134627

Abstract

ObjectiveThis study was conducted to assess the reproducibility and validity of a food frequency questionnaire (FFQ) that was developed to assess the overall dietary consumption via dietary pattern method in a rural population in southwest China.MethodsA total of 179 participants aged between 40 and 70 years old were included in this study. Participants administered FFQ at baseline (FFQ1) and one year later (FFQ2) to assess the reproducibility. Six 3-day 24-hour recalls (24HRs) were completed between the administrations of two FFQs to determine the validity. Dietary patterns from three separate dietary sources were derived by using principle component factor analysis. Comparisons between dietary pattern scores were made by using Pearson or intraclass correlation coefficient, cross-classification analysis, weighted kappa (κ) statistic and Bland-Altman analysis. The de-attenuated method was adopted to correct the monthly and seasonally variation and the partial correlation analysis was used correct the influence by total energy intake.ResultsTwo major dietary factors, labeled as prudent pattern and processed food pattern, were identified. The prudent pattern was characterized by higher factor loadings of wheat, rice, fresh vegetables, bean products, nuts, red meat, white meat and fresh eggs; and the processed food pattern was characterized by higher factor loadings of pickled vegetables, preserved vegetables and salted meat. Between Two FFQs, intraclass correlation coefficients were 0.57 for prudent pattern and 0.55 for processed food pattern, partial Pearson correlation coefficients were 0.51 for the prudent pattern and 0.56 for the processed food pattern; weighted κ statistic ranged from 0.45 (for the prudent pattern) to 0.56 (for the processed food pattern). Between FFQs and 24HRs, de-attenuated correlation coefficients ranged from 0.54 to 0.78 for the prudent pattern and from 0.55 to 0.61 for the processed food pattern; partial Pearson correlation coefficients ranged from 0.41 to 0.56 for the prudent pattern and from 0.42 to 0.44 for the processed food pattern; weighted κ statistic ranged from 0.42 to 0.46 for prudent pattern and from 0.43 to 0.60 for processed food pattern. The Bland-Altman plots and limits of agreement indicated that the deviation/divergence was not obvious for both of the patterns between FFQ1 and FFQ2 and between FFQs and 24HRs.ConclusionThe study suggests that the FFQ is reasonably reproducible and valid to assess the overall dietary consumption via dietary pattern methods in the Chinese rural population.

Highlights

Epidemiological studies have suggested that diet and lifestyle are becoming a major issue that influences the population health
The prudent pattern was characterized by higher factor loadings of wheat, rice, fresh vegetables, bean products, nuts, red meat, white meat and fresh eggs; and the processed food pattern was characterized by higher factor loadings of pickled vegetables, preserved vegetables and salted meat
The study suggests that the food frequency questionnaire (FFQ) is reasonably reproducible and valid to assess the overall dietary consumption via dietary pattern methods in the Chinese rural population

Summary

Introduction

Epidemiological studies have suggested that diet and lifestyle are becoming a major issue that influences the population health. A food frequency questionnaire (FFQ) directed to the dietary exposure of conceptual interest in most applications is a comparatively inexpensive and easyadministered approach for assessing long-term dietary habits in large population groups.[1] FFQ is sensitive to the diverse lifestyle, eating habits and dietary preferences in the population concerned.[2] validation of such an assessment instrument is important, because it may provide valuable insights into the pros and cons of FFQ used in epidemiological studies.[3] Dietary pattern is an integrated and comprehensive method. Dietary patterns can represent the totality of a diet and provide a valuable alternative to measure single nutrients/food intake, and they have been used to explore the diet-disease relationships. Dietary patterns can represent the totality of a diet and provide a valuable alternative to measure single nutrients/food intake, and they have been used to explore the diet-disease relationships. [4,5]

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Conclusion