Pereira Taísa Sabrina Silva, Cade Nágela Valadão, Mill José Geraldo, Sichieri Rosely, Molina Maria Del Carmen Bisi
Post Graduate Programme in Public Health, Federal University of Espírito Santo, Espírito Santo, Brazil.
Institute of Social Medicine, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS One. 2016 Dec 28;11(12):e0169085. doi: 10.1371/journal.pone.0169085. eCollection 2016.
Biomarkers are a good choice to be used in the validation of food frequency questionnaire due to the independence of their random errors.
To assess the validity of the potassium and sodium intake estimated using the Food Frequency Questionnaire ELSA-Brasil.
SUBJECTS/METHODS: A subsample of participants in the ELSA-Brasil cohort was included in this study in 2009. Sodium and potassium intake were estimated using three methods: Semi-quantitative food frequency questionnaire, 12-hour nocturnal urinary excretion and three 24-hour food records. Correlation coefficients were calculated between the methods, and the validity coefficient was calculated using the method of triads. The 95% confidence intervals for the validity coefficient were estimated using bootstrap sampling. Exact and adjacent agreement and disagreement of the estimated sodium and potassium intake quintiles were compared among three methods.
The sample consisted of 246 participants, aged 53±8 years, 52% of women. Validity coefficient for sodium were considered weak (рfood frequency questionnaire actual intake = 0.37 and рbiomarker actual intake = 0.21) and moderate (рfood records actual intake 0.56). The validity coefficient were higher for potassium (рfood frequency questionnaire actual intake = 0.60; рbiomarker actual intake = 0.42; рfood records actual intake = 0.79). Conclusions: The Food Frequency Questionnaire ELSA-Brasil showed good validity in estimating potassium intake in epidemiological studies. For sodium validity was weak, likely due to the non-quantification of the added salt to prepared food.
生物标志物因其随机误差的独立性，是用于验证食物频率问卷的良好选择。
评估使用巴西成人健康纵向研究（ELSA-Brasil）食物频率问卷估算的钾和钠摄入量的有效性。
对象/方法：2009年，本研究纳入了ELSA-Brasil队列研究的部分参与者。采用三种方法估算钠和钾的摄入量：半定量食物频率问卷、12小时夜间尿排泄量以及三份24小时饮食记录。计算各方法之间的相关系数，并采用三联法计算有效性系数。使用自助抽样法估算有效性系数的95%置信区间。比较三种方法估算的钠和钾摄入量五分位数的精确一致性和相邻一致性及不一致性。
样本包括246名参与者，年龄53±8岁，52%为女性。钠的有效性系数被认为较弱（食物频率问卷与实际摄入量的相关系数р = 0.37，生物标志物与实际摄入量的相关系数р = 0.21），而对于钾则为中等（食物记录与实际摄入量的相关系数р = 0.56）。钾的有效性系数较高（食物频率问卷与实际摄入量的相关系数р = 0.60；生物标志物与实际摄入量的相关系数р = 0.42；食物记录与实际摄入量的相关系数р = 0.79）。结论：在流行病学研究中，巴西成人健康纵向研究食物频率问卷在估算钾摄入量方面显示出良好的有效性。对于钠，有效性较弱，可能是由于未对加工食品中添加的盐进行量化。
