Cowin I, Emmett P
Division of Paediatric and Perinatal Epidemiology, Institute of Child Health, University of Bristol, Bristol, UK.
Eur J Clin Nutr. 1999 Nov;53(11):891-4. doi: 10.1038/sj.ejcn.1600873.
To assess the degree of underestimation of nutrient intakes caused by missing data in McCance and Widdowson's food tables and supplements, the standard food tables used in the UK.
1026 children aged 18 months.
A research clinic in Bristol.
A 3-day dietary diary was completed for each child. These were coded and analysed using a database consisting of the unedited information in the food tables, to produce a set of 'uncorrected' nutrient intakes. 'Guesstimated' values for nutrient content were then added to our nutrient database in place of the missing values in the food tables, and the daily nutrient intakes were recalculated.
Calculated daily nutrient intakes before and after substituting missing data in the food tables for guesstimated values.
Of the 1027 foods used in the analysis, 540 had missing data for one or more nutrient content. For several of the nutrients examined adding guesstimated values altered the calculated nutrient intake of more than 90% of the subjects. However, for nutrients such as the B vitamins and the major minerals the mean percentage underestimate was very small. We calculated the underestimation of nutrient intake to be largest for vitamins E and D (13.8% and 14.7%, respectively). The effect of missing data on calculated nutrient intakes was proportionately greater at the bottom end of the nutrient intake distribution.
Missing data has a fairly small effect on calculated mean daily intakes. However, it can result in some individuals being misranked within a nutrient intake distribution. The availability of a standard set of 'guesstimates' to use in place of missing data would reduce this problem, and would improve comparability between dietary surveys.
评估英国使用的标准食物表——麦坎斯和威多森食物表及增补剂中缺失数据所导致的营养素摄入量低估程度。
1026名18个月大的儿童。
布里斯托尔的一家研究诊所。
为每个儿童完成一份为期3天的饮食日记。使用包含食物表中未编辑信息的数据库对这些日记进行编码和分析，以得出一组“未校正”的营养素摄入量。然后将营养素含量的“推测”值添加到我们的营养素数据库中，以取代食物表中的缺失值，并重新计算每日营养素摄入量。
用推测值替代食物表中的缺失数据前后计算出的每日营养素摄入量。
在分析中使用的1027种食物中，540种有一种或多种营养素含量缺失数据。对于所检测的几种营养素，添加推测值改变了超过90%受试者的计算营养素摄入量。然而，对于维生素B族和主要矿物质等营养素，平均低估百分比非常小。我们计算出维生素E和维生素D的营养素摄入量低估最大（分别为13.8%和14.7%）。在营养素摄入量分布的低端，缺失数据对计算出的营养素摄入量的影响成比例地更大。
缺失数据对计算出的平均每日摄入量影响相当小。然而，它可能导致一些个体在营养素摄入量分布中的排名错误。提供一组标准的“推测值”来替代缺失数据将减少这个问题，并将提高饮食调查之间的可比性。
