Van Staveren W A, Burema J, Deurenberg P, Katan M B
Wageningen Agricultural University, Department of Human Nutrition, The Netherlands.
Int J Epidemiol. 1988 Dec;17(4):964-9. doi: 10.1093/ije/17.4.964.
Day-to-day variation within an individual's dietary intake may obscure associations between diet and disease. We calculated the extent of misclassification of subjects by dietary polyunsaturated to saturated fatty acid (P/S) ratio for 1, 3, 7 and 19 survey days per person. In 59 young women diet was estimated 19 times over a period of two and a half years by a 24-hour recall method. The dietary P/S ratio was compared with the P/S ratio in adipose tissue biopsies, which was used as the reference. The proportion of subjects properly classified increased with the number of survey days. Between three and seven recalls appeared to be most cost effective. The effect of misclassification on the observed odds ratio in a case-control study was calculated for a hypothetical distribution of exposure for cases and controls.
个体饮食摄入量的日常变化可能会掩盖饮食与疾病之间的关联。我们计算了每人1天、3天、7天和19天调查期内，根据膳食多不饱和脂肪酸与饱和脂肪酸（P/S）比值对受试者进行错误分类的程度。在59名年轻女性中，通过24小时回忆法在两年半的时间里对她们的饮食进行了19次评估。将膳食P/S比值与作为参考的脂肪组织活检中的P/S比值进行比较。正确分类的受试者比例随着调查天数的增加而增加。3至7次回忆似乎最具成本效益。针对病例和对照的假设暴露分布，计算了病例对照研究中错误分类对观察到的优势比的影响。
