Wu M L, Whittemore A S, Jung D L
Am J Epidemiol. 1986 Nov;124(5):826-35. doi: 10.1093/oxfordjournals.aje.a114459.
Measures for quantifying reproducibility and between-subject variability of nutrient intake data are applied to intakes reported in two interviews (1-3 months apart) by 44 male and 17 female healthy white subjects aged 45-75 years. Intakes were assessed by three methods: a dietary history that included consumption frequency and serving size for 71 food items (dietary history method); a combination of individual consumption frequencies with sex-specific mean serving sizes (frequency method); an extrapolation from frequencies and serving sizes of all foods reported for a "typical day" in the specified time period (typical day method). Intake variation within subjects, between subjects, and between methods was assessed by analysis of variance for each sex and for each of the nutrients: total calories, protein, fat, vitamin A, and protein and fat as percentage of total calories. Dietary history-assessed intakes exceeded those assessed by the other two methods. The dietary history versus frequency excess was greater than the dietary history versus typical day excess for calories, fat, and protein, while the reverse was true for vitamin A and fat as percentage of total calories. The typical day method was unreliable for vitamin A because it occasionally produced extremely high, unreproducible intakes. The intraclass correlation coefficient was used to measure a method's ability to distinguish interpersonal variation from within-person error. The frequency method produced less within-person error than did the dietary history method for all nutrients. For absolute intakes, the frequency method produced less interpersonal variation than did the dietary history method, while for relative intakes, the reverse was true. Females reported intakes with less within-person error than did males, and the interpersonal spread of their intakes was smaller. Consequences of these findings for the power and sensitivity of studies on the role of dietary factors in the etiology of chronic disease are explored.
对44名年龄在45至75岁之间的健康白人男性和17名健康白人女性在两次访谈（间隔1至3个月）中报告的营养素摄入量数据应用了量化再现性和个体间变异性的方法。摄入量通过三种方法进行评估：一种饮食史调查，涵盖71种食物的消费频率和食用量（饮食史法）；个体消费频率与按性别划分的平均食用量相结合的方法（频率法）；根据特定时间段内“典型一天”报告的所有食物的频率和食用量外推得出（典型日法）。通过对每种性别和每种营养素（总热量、蛋白质、脂肪、维生素A以及蛋白质和脂肪占总热量的百分比）进行方差分析，评估了个体内、个体间以及不同方法之间的摄入量差异。饮食史评估的摄入量超过了其他两种方法评估的摄入量。对于热量、脂肪和蛋白质，饮食史与频率法之间的差异大于饮食史与典型日法之间的差异，而对于维生素A以及脂肪占总热量的百分比，情况则相反。典型日法对于维生素A不可靠，因为它偶尔会产生极高的、不可重复的摄入量。组内相关系数用于衡量一种方法区分人际差异和个体内误差的能力。对于所有营养素，频率法产生的个体内误差均小于饮食史法。对于绝对摄入量，频率法产生的人际差异小于饮食史法，而对于相对摄入量，情况则相反。女性报告的摄入量个体内误差小于男性，且其摄入量的人际分布范围更小。探讨了这些发现对饮食因素在慢性病病因学中作用的研究的效能和敏感性的影响。
