Reproducibility and validity of an FFQ in the Henan Rural Cohort Study.

OBJECTIVE: The present study aimed to evaluate the validity and reproducibility of a thirteen-item FFQ regarding identification of dietary conditions in a rural population in China. DESIGN: A reproducibility study repeated the first FFQ (FFQ1) approximately 4 weeks later (FFQ2). A validity study evaluated the mean of three consecutive 24 h diet recalls as the reference measure. SETTING: Cross-sectional study. PARTICIPANTS: Residents of a rural area in Henan Province, which is located in the central region of China. RESULTS: A total of 295 individuals participated in the reproducibility study. In addition, 123 people agreed to participate in the validity study. Spearman's correlation coefficients between the two FFQ ranged from 0·06 (vegetables) to 0·58 (eggs). Spearman's correlation coefficients between the two methods of collection ranged from 0·01 for cereal to 0·49 for staple foods. The mean of the intraclass correlation coefficients of the two FFQ (FFQ1 v. FFQ2) was 0·19. Bland-Altman analysis indicated good agreement for most food groups across the range of intake for the two studies. CONCLUSIONS: The study demonstrated that our FFQ design could be used as a representative tool to conduct a dietary evaluation of a rural population.