Reproducibility and validity of dietary polyphenols derived from 24-hour dietary recalls in the Anhui Lifestyle Validation Study

Abstract

Abstract While 24-hour dietary recalls (24HDRs) are increasingly used to assess polyphenol-disease associations, their performance for measuring total dietary polyphenols and their subclasses remains unknown. In the Anhui Lifestyle Validation Study, 432 community-dwelling adults completed 12-day dietary recalls, structured as 4 seasonal sets of 3 consecutive 24HDRs (2 weekdays and 1 weekend day each) between July 2021 and July 2022. Reproducibility of dietary total polyphenols, flavonoids, lignans and phenolic acids assessed by different number of non-consecutive 24HDRs was evaluated by intraclass correlation coefficient (ICC). Relative validity was evaluated by comparing estimates from different numbers of 24HDRs with the internal reference using deattenuated Spearman correlation coefficients ( r c ). The reproducibility from 2 24HDRs was weak for these 4 polyphenol categories (ICC: 0.10–0.39), while 3 24HDRs yielded a reasonable reproducibility for total polyphenols (ICC: 0.40, 95% CI: 0.31-0.50), flavonoids (ICC: 0.42, 95% CI: 0.33-0.51), and phenolic acids (ICC: 0.45, 95% CI: 0.16-0.66), but not for lignans (ICC: 0.11, 95% CI: 0.01-0.26). Increasing recall days up to 4–6 seemed not to appreciably improve the reproducibility (ICC range: 0.13-0.17 for lignans, 0.41-0.56 for other polyphenols). The relative validity against the internal reference of these 4 polyphenol categories was moderate for 2 24HDRs ( r c : 0.50-0.74) and improved for ≥ 3 24HDRs ( r c : 0.76-1.00). Older age, female sex, and weekend administration were associated with lower reproducibility of 3 24HDR-based assessments of phenolic acids or flavonoids. Overall, our results suggest that 3 non-consecutive 24HDRs may have acceptable performance in measuring most dietary polyphenol intake except for lignans.