Division of Research, Kaiser Permanente Northern California, Oakland, California 94612, USA.
Am J Epidemiol. 2010 Dec 1;172(11):1315-23. doi: 10.1093/aje/kwq284. Epub 2010 Oct 11.
Multiple-day diet records can be unsuitable for cohort studies because of high administrative and analytical costs. Costs could be reduced if a subsample of participants were analyzed in a nested case-control study. However, completed records are usually reviewed ("documented") with participants to correct errors and omissions before analysis. The authors evaluated the suitability of using undocumented 3-day food records in 2 samples of women in a Northern California cohort study of breast cancer survivorship (2006-2009). One group of participants (n = 130) received an introduction to the food record at enrollment, while another (n = 70) received more comprehensive instruction. Food records were mailed to participants 6 months later for follow-up and were analyzed as received and after phone documentation. Error rates for adequate completion were high in the first group but substantially lower among persons receiving instruction; prevalences of missing data on serving size and incomplete food descriptions changed from 30% to 4% and from 32% to 6%, respectively (P < 0.0001). Correlations between nutrient intakes calculated from undocumented and documented records were 0.72-0.93 in the first group and were significantly stronger (0.84-0.99) among persons receiving instruction. Documentation had little effect on intraclass correlation coefficients across days, but training increased the coefficients for many nutrients. When participants receive proper instruction, undocumented food records can be satisfactory for large epidemiologic studies.
多日饮食记录可能不适合队列研究，因为其行政和分析成本较高。如果在嵌套病例对照研究中分析参与者的亚组，可以降低成本。然而，在分析之前，通常会与参与者一起审查（“记录”）完成的记录，以纠正错误和遗漏。作者评估了在加利福尼亚北部乳腺癌生存队列研究（2006-2009 年）的 2 个女性样本中使用未经记录的 3 天食物记录的适宜性。一组参与者（n=130）在入组时接受了食物记录介绍，而另一组（n=70）接受了更全面的指导。6 个月后，将食物记录邮寄给参与者进行随访，并在收到和电话记录后进行分析。第一组中，适当完成的错误率很高，但接受指导的人的错误率大大降低；在接受指导的人群中，关于份量和食物描述不完整的数据缺失率从 30%降至 4%，从 32%降至 6%（P<0.0001）。未记录和记录文档中计算出的营养素摄入量之间的相关性在第一组中为 0.72-0.93，在接受指导的人群中相关性显著更强（0.84-0.99）。记录对日内的组内相关系数几乎没有影响，但培训增加了许多营养素的系数。当参与者接受适当的指导时，未经记录的食物记录可以满足大型流行病学研究的需要。
