食物频率法评估贫血学生膳食铁摄入量的相对效度研究

Relative validity of food frequency questionnaire for estimating dietary iron intake of students with anemia

目的以称重记录法结合24小时回顾法为参考方法,评估食物频率法应用于调查贫血学生膳食铁摄入量及其相关营养素和食物摄入量的相对效度。方法分别应用称重记录法结合24小时回顾法和食物频率法对156名10～14岁在校贫血学生进行膳食调查,计算平均每日膳食铁、血红素铁、非血红素铁、抗坏血酸、畜肉/禽肉/鱼肉和蛋类摄入量,采用Wilcoxon配对秩和检验、Spearman秩相关分析、交叉归类分析、替代分类的真实值分析评估食物频率法的准确度。结果与参考方法相比,食物频率法高估了贫血学生膳食铁摄入量及其相关营养素和食物摄入量,与参考方法调查结果的相关性较低。交叉归类分析、替代分类的真实值分析结果显示,食物频率法不能很好的区分营养素摄入量的不同水平。结论食物频率法应用于调查贫困地区贫血学生的膳食铁及相关营养素摄入量水平的准确性较低。

Objective To assess the relative validity of food frequency questionnaire（FFQ）for estimating dietary iron and its related nutrients and food intakes of students with anemia.Methods FFQ and weighed dietary records combining with 24h dietary recalls（adopted as reference method）were applied respectively to investigate the diet of 156 anemic students aged 10~12 years.The average dietary intakes of iron,haem iron,non-haem iron,vitamin C,meat/fish/poultry and eggs were estimated.Wilcoxon matched-pairs signed-rank test,Spearman＇s rank correlation,cross-classification and actual values for surrogate categories were performed to assess the relative validity of FFQ.Results Compared with the reference method,dietary iron and its related nutrients and food intakes were overestimated by FFQ,and bear poor correlation with reference method.The results of cross-classification and actual values for surrogate categories indicated that the low and high intakes of all dietary components could not be clearly differentiated by FFQ.Conclusion FFQ presents unsatisfactory accuracy in assessing dietary intakes of iron and related nutrients of anemic students in less developed districts.