Department of Children Health and Hygiene, School of Public Health, Harbin Medical University, Harbin, China.
PLoS One. 2011 May 11;6(5):e19656. doi: 10.1371/journal.pone.0019656.
This study aims to evaluate the reproducibility and validity of a food frequency questionnaire (FFQ) developed for female adolescents in the Suihua area of North China. The FFQ was evaluated against the average of 24-hour dietary recalls (24-HRs).
METHODOLOGY/PRINCIPAL FINDINGS: A total of 168 female adolescents aged 12 to 18 completed nine three consecutive 24-HRs (one three consecutive 24 HRs per month) and two FFQs over nine months. The reproducibility of the FFQ was estimated using intraclass correlation coefficients (ICCs), and its relative validity was assessed by comparing it with the 24-HRs. The mean values of the 24-HRs were lower than those of the FFQs, except for protein (in FFQ1) and iron (in FFQ2). The ICCs for all nutrients and food groups in FFQ1 and FFQ2 were moderately correlated (0.4-0.8). However, all the ICCs decreased after adjusting for energy. The weighted κ statistic showed moderate agreement (0.40-0.6) for all nutrients and food groups, except for niacin and calcium, which showed poor agreement (0.35). The relative validity results indicate that the crude Spearman's correlation coefficients of FFQ1 and the 24-HRs ranged from 0.41 (for Vitamin C) to 0.65 (for fruit). The coefficients of each nutrient and food group in FFQ2 and the 24-HRs were higher than those in FFQ1 and the 24-HRs, indicating good correlation. Although all energy-adjusted Spearman's correlation coefficients were lower than the crude coefficients, de-attenuation to correct for intra-individual variability improved the correlation coefficients. The weighted κ coefficients of nutrients and food groups ranged from 0.32 for beans to 0.52 for riboflavin in FFQ1 and the 24-HRs, and 0.32 for Vitamin C to 0.54 for riboflavin in FFQ2 and the 24-HRs.
The FFQ developed for female adolescents in the Suihua area is a reliable and valid instrument for ranking individuals within this study.
本研究旨在评估为中国北方绥化市的女性青少年开发的食物频率问卷（FFQ）的可重复性和有效性。该 FFQ 与 24 小时膳食回忆（24-HR）的平均值进行了评估。
方法/主要发现：共有 168 名年龄在 12 至 18 岁的女性青少年在九个月内完成了九次连续三天的 24-HR（每月一次连续三天的 24-HR）和两次 FFQ。使用组内相关系数（ICC）评估 FFQ 的可重复性，并通过与 24-HR 进行比较来评估其相对有效性。24-HR 的平均值低于 FFQ 的平均值，除了蛋白质（在 FFQ1 中）和铁（在 FFQ2 中）。FFQ1 和 FFQ2 中所有营养素和食物组的 ICC 中度相关（0.4-0.8）。然而，所有 ICC 在调整能量后均降低。所有营养素和食物组的加权κ统计量显示出中度一致性（0.40-0.6），除了烟酸和钙，它们显示出较差的一致性（0.35）。相对有效性结果表明，FFQ1 和 24-HR 的粗 Spearman 相关系数范围从 0.41（维生素 C）到 0.65（水果）。FFQ2 和 24-HR 中每个营养素和食物组的系数均高于 FFQ1 和 24-HR，表明相关性良好。虽然所有经能量调整的 Spearman 相关系数均低于粗系数，但去衰减以纠正个体内变异性可提高相关系数。FFQ1 和 24-HR 中营养素和食物组的加权κ系数范围从豆类的 0.32 到核黄素的 0.52，FFQ2 和 24-HR 中维生素 C 的 0.32 到核黄素的 0.54。
为绥化市女性青少年开发的 FFQ 是一种可靠且有效的工具，可用于对研究中的个体进行排名。
