Brussaard J H, Brants H A, Bouman M, Löwik M R
TNO Nutrition and Food Research Institute, Zeist, The Netherlands.
Eur J Clin Nutr. 1997 Nov;51 Suppl 3:S19-24.
To test the representativity of the study population and to identify potential selection bias.
Non-response analysis and comparison with other representative samples from the Dutch population. Description of physical and clinical biochemical variables as well as health and lifestyle characteristics among low vitamin B6 groups and reference groups.
The non-response rate for the food frequency questionnaire was 54%; subsequently, non-response for the detail study was 42%. A greater proportion of respondents to the FFQ and of participants in the reference group of the study followed a special dietary regimen or a therapeutic diet or used dietary supplements compared with non-respondents, indicating that we may have selected a somewhat more health conscious reference group. There were no differences in vitamin B6 intake (absolute or per g protein) between participants and the total group of non-respondents for the detail study. Selection of a low B6 group did not result in important bias regarding physical, biochemical or general health and lifestyle characteristics. Exceptions were a difference in the proportion of dieters (younger women) and supplement users (older women) and a difference in creatinine clearance and supplement use between reference and low B6 groups. The differences found, however, were small. Nonetheless, these factors have to be taken into account when analysing and interpreting the results.
检验研究人群的代表性并识别潜在的选择偏倚。
无应答分析以及与荷兰人群中其他代表性样本进行比较。描述低维生素B6组和参照组的身体及临床生化变量以及健康和生活方式特征。
食物频率问卷的无应答率为54%；随后，详细研究的无应答率为42%。与无应答者相比，食物频率问卷的应答者以及研究参照组中的参与者中，有更大比例的人遵循特殊饮食方案或治疗性饮食，或使用膳食补充剂，这表明我们可能选择了一个健康意识稍强的参照组。在详细研究中，参与者与无应答者总体之间的维生素B6摄入量（绝对量或每克蛋白质中的量）没有差异。选择低B6组在身体、生化或一般健康及生活方式特征方面未导致重大偏倚。例外情况是节食者（年轻女性）和补充剂使用者（老年女性）的比例存在差异，以及参照组和低B6组之间肌酐清除率和补充剂使用情况存在差异。然而，所发现的差异较小。尽管如此，在分析和解释结果时必须考虑这些因素。
