Abstract P2-13-19: Validation of a Chinese-specific food frequency questionnaire for assessing dietary lignans intake among breast cancer patients in Hong Kong
Authors: He Yiqian , Lei Yuan-Yuan , Kwok Carol , Cheng Ashley , Cheung Ka-Li , Lee Iris , Lee Roselle , Ho Suzanne , Yeo Winnie 
Published: March 2020

Abstract
Background: Lignans intake has been suggested to affect breast cancer outcomes based on a few studies from the West. However, to date, the relationship of lignan consumption and breast cancer outcomes has not been investigated in Chinese patient population. Since the habitual intake of lignan and food sources for lignan may vary between different geographical population and ethnicities, it is necessary to develop a population-specific Food Frequency Questionnaire (FFQ) to enable the conduct of dietary lignan studies in Chinese patient population. The objective of this study is to validate a modified FFQ that could be utilized for assessing lignan intake in a Chinese population.
Methods: 133 Hong Kong Chinese women with early-stage breast cancer who were participating in an on-going prospective cohort study (The Hong Kong New Territories East Cluster (NTEC)-Kowloon West Cluster (KWC) Breast Cancer Survival Study) were being consented into the present study; the NTEC-KWC study investigates the associations of phytoestrogens and other factors with breast cancer outcomes. 103 of the 133 patients completed all the study assessments and were included in the analysis; they underwent two face-to-face interviews during which they responded to a modified 130-item FFQ at 1-year apart (FFQ1, FFQ2). In addition, 12 monthly 24-hour dietary recalls (24-h DRs) were conducted through telephone during the same 1-year period. Total lignans intake from the FFQs and 24-h DRs, correlation coefficients and cross classification between the two FFQs and between FFQ and 24-h DR were examined.
Results: Median intakes of total lignans for FFQ1, FFQ2 and 24-h DRs were 2.39, 2.15 and 1.36 mg/day, respectively. Both the energy-adjusted correlation coefficients between FFQ1 and FFQ2, and that between FFQ2 and 24-h DR were 0.59 for log-transformed lignans intake (p&lt;0.001). Correct classification of participants into the same quartiles of energy-adjusted lignans intake between 2 FFQs and between FFQ2 and 24-h DR were 37.9% and 40.8%, respectively. Misclassification of participants into the extreme quartiles occurred in 7.8% and 2.9% of the studied patients, respectively. The reproducibility between lignans intake assessed by the 2 FFQs conducted was 0.59 (p&lt;0.001) for energy-adjusted lignans intake after log transformation.
Conclusion: The 130-item FFQ has acceptable validity and reproducibility, and is a reasonable and useful instrument to assess dietary lignans intake among Hong Kong Chinese women with early-stage breast cancer.
Funding: World Cancer Research Fund International (Grant Number WCRF 2010/249 and WCRF 2014/1197)
Citation Format: Yiqian He, Yuan-Yuan Lei, Carol Kwok, Ashley Cheng, Ka-Li Cheung, Iris Lee, Roselle Lee, Suzanne Ho, Winnie Yeo. Validation of a Chinese-specific food frequency questionnaire for assessing dietary lignans intake among breast cancer patients in Hong Kong [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-13-19.