Validity of a semi-quantitative food frequency questionnaire for estimating dietary intake of antioxidant vitamins and fatty acids

为了评估我们为大规模前瞻性研究开发并使用的半定量食物频率问卷（FFQ）的有效性，我们将FFQ估计的抗氧化维生素（如α-和β-胡萝卜素，维生素C）和脂肪酸（如EPA，DHA）的摄入量与4次7天饮食记录（DR）进行了比较。血清抗氧化维生素和脂肪酸也进行了测量。调整能量摄入后，胡萝卜素和维生素C摄入量的FFQ和DR之间的相关系数在男性中均为0.44，在女性中分别为0.39和0.23。调整总脂肪酸摄入量后，男性的EPA和DHA值分别为0.47和0.46，女性为0.52和0.47。FFQ与血清β-胡萝卜素、α-胡萝卜素和维生素C水平的相关系数分别为-0.02，0.21和-0.13，与血清EPA和DHA组成的相关系数分别为0.47和0.41。我们的结论是，我们的FFQ估计胡萝卜素，维生素C和脂肪酸是合理的估计每种营养素的大规模流行病学研究中的日常膳食摄入水平。

To evaluate the validity of a semi-quantitative food frequency questionnaire (FFQ) which we developed for and used in a large scale prospective study, we compared the estimated intake level of antioxidant vitamins (e.g. alpha- and beta-carotene, vitamin C) and fatty acids (e.g. EPA, DHA) by FFQ with those by 4 time 7-day dietary records (DR). Serum antioxidant vitamins and fatty acids were also measured. The correlation coefficients between FFQ and DR for carotene and vitamin C intake were both 0.44 in men, and 0.39 and 0.23 in women, respectively, after adjusting for energy intake. Those values for EPA and DHA were 0.47 and 0.46 in men and 0.52 and 0.47 in women, after adjusting for total fatty acid intake. The correlation coefficient between FFQ with serum level of beta-, alpha-carotene, and vitamin C were -0.02, 0.21, and-0.13, respectively, and those with serum composition of EPA and DHA were 0.47 and 0.41, respectively. We conclude that the estimates of carotene, vitamin C and fatty acids by our FFQ are reasonable to estimate usual dietary intake level of each nutrient in large scale epidemiological study.