Validation of an FFQ to assess short-term antioxidant intake against 30 d food records and plasma biomarkers

Abstract Objective To validate a brief FFQ developed for capturing short-term antioxidant intake in a sample of US college students. Design A seventy-four-item antioxidant FFQ was developed based on major antioxidant sources in the American diet. The FFQ was validated against 30 d food records (FR) and plasma antioxidant concentrations. The reliability of the FFQ was evaluated by two FFQ administered at a 1-month interval. Settings University of Connecticut, CT, USA. Subjects Sixty healthy college students. Results Estimates of dietary antioxidants from the FFQ were moderately to highly correlated with those estimated from the 30 d FR (r = 0·29–0·80; P < 0·05) except for γ-tocopherol and β-cryptoxanthin. Total antioxidant capacity from diet only or from diet and supplements estimated by the 30 d FR and FFQ were highly correlated (r = 0·67 and 0·71, respectively; P < 0·0001). The FFQ categorized 91 % of participants into the same or adjacent tertiles of antioxidant intake as the 30 d FR. Most dietary carotenoids estimated from the FFQ were correlated with plasma levels (P < 0·05). Correlation coefficients for test–retest reliability ranged from 0·39 to 0·86. More than 94 % of the participants were classified in the same or adjacent tertiles between the two administrations of the FFQ. Conclusions The brief FFQ demonstrated reasonable validity for capturing a comprehensive antioxidant intake profile. This FFQ is applicable in epidemiological or clinical studies to capture short-term antioxidant intake or to simply document the variations of antioxidant intake in intervention trials. Cross-validation studies are warranted in other target populations.

摘要 目的 验证一份为获取美国大学生短期抗氧化剂摄入量而编制的简短食物频率问卷（FFQ）。 设计 基于美国饮食中主要的抗氧化剂来源编制了一份含74项的抗氧化剂食物频率问卷。该问卷通过30天食物记录（FR）和血浆抗氧化剂浓度进行验证。通过间隔1个月进行两次食物频率问卷来评估其可靠性。 地点 美国康涅狄格州康涅狄格大学 受试者 60名健康大学生 结果 食物频率问卷所得的膳食抗氧化剂估计值与30天食物记录所得估计值呈中度到高度相关（r = 0.29 - 0.80；P < 0.05），但γ - 生育酚和β - 隐黄质除外。仅由饮食或由饮食及补充剂提供的总抗氧化能力，通过30天食物记录和食物频率问卷估计的值高度相关（r分别为0.67和0.71；P < 0.0001）。食物频率问卷将91%的参与者划分到与30天食物记录相同或相邻的抗氧化剂摄入量三分位数类别中。食物频率问卷估计的大多数膳食类胡萝卜素与血浆水平相关（P < 0.05）。重测信度的相关系数范围为0.39 - 0.86。超过94%的参与者在两次食物频率问卷施测中被划分到相同或相邻的三分位数类别。 结论 这份简短的食物频率问卷在获取全面的抗氧化剂摄入概况方面显示出合理的有效性。该问卷适用于流行病学或临床研究，以获取短期抗氧化剂摄入量，或在干预试验中简单记录抗氧化剂摄入量的变化。有必要在其他目标人群中进行交叉验证研究。